- Basic principles for selecting pumps
- Technological and design requirements
- The nature of the pumped medium
- Main design parameters
- Areas of application (selection) of pumps according to the generated pressure
- Applications (selection) of pumps by performance
- The main design parameters of pumps (capacity, head, power)
- Performance calculation for various pumps. Formulas
- Piston pumps
- Gear pumps
- Screw pumps
- calculation of the volumetric efficiency of a plunger pump
- calculation of the required power of the electric motor of a two-piston pump
- calculation of the head loss of a three-piston pump
- calculation of the volumetric efficiency of a screw pump
- calculation of pressure, flow and useful power centrifugal pump
- calculation of the feasibility of pumping water with a centrifugal pump
- calculation of the feed rate of a gear (gear) pump
- determine if the pump meets the starting torque requirements
- calculation of net power of a centrifugal pump
- calculation of the maximum increase in pump flow
Basic principles for selecting pumps
The choice of pumping equipment is a crucial stage, on which both the technological parameters and the performance of the designed installation will depend. When choosing a pump type, three groups of criteria can be distinguished:
1) Technological and design requirements
2) Nature of the pumped medium
3) Basic design parameters
Technological and design requirements:
In some cases, the choice of a pump may be dictated by some strict requirements for a number of design or process parameters. Centrifugal pumps, unlike piston pumps, can provide a uniform supply of the pumped medium, while in order to fulfill the conditions of uniformity on a piston pump, it is necessary to significantly complicate its design by placing several pistons on the crankshaft that perform reciprocating movements with a certain lag from each other . At the same time, the supply of the pumped medium in discrete portions of a given volume can also be a technological requirement. An example of defining design requirements would be the use of submersible pumps where it is necessary or only possible to locate the pump below the level of the pumped liquid.
Technological and design requirements for a pump are rarely decisive, and ranges of suitable pump types for various specific applications are known from human experience, so a thorough listing of them is not necessary.
The nature of the pumped medium:
The characteristics of the pumped medium often become a determining factor in the selection of pumping equipment. Various types of pumps are suitable for pumping a wide variety of media, differing in viscosity, toxicity, abrasiveness and many other parameters. So screw pumps are capable of pumping viscous media with various inclusions without damaging the structure of the medium, and can be successfully used in Food Industry for pumping jams and pastes with various fillers. The corrosive properties of the pumped medium determine the material design of the selected pump, and toxicity determines the level of its sealing.
Main design parameters:
The operating requirements of various industries can be met by several types of pumps. In such a situation, preference is given to the type of pumps that is most applicable for specific values of the main design parameters (capacity, pressure and power consumption). Below are tables, in general terms, reflecting the limits of application of the most common types of pumps.
Areas of application (selection) of pumps according to the generated pressure
|
up to 10 m |
From 10 |
From 100 |
From 1 000 |
From 10 000 |
|
single stage |
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Multistage |
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Axial |
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|
Piston |
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screw |
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Plunger |
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Vortex |
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Applications (selection) of pumps by performance
|
Up to 10 m3/h |
From 10 |
From 100 up to 1,000 m3/h |
From up to 10,000 m3/h |
From |
|
single stage |
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|
Multistage |
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|
Axial |
||||
|
Piston |
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|
screw |
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|
Plunger |
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|
Vortex |
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Only a pump that meets all three groups of criteria can guarantee long-term and reliable operation.
Basic design parameters of pumps
Despite the variety of machines for pumping liquids and gases, a number of basic parameters can be distinguished that characterize their work: productivity, power consumption and pressure.
Performance(supply, flow) - the volume of the medium pumped by the pump per unit of time. Denoted by the letter Q and has the dimension of m 3 / hour, l / s, etc. The flow rate includes only the actual volume of the transported liquid, excluding back leakage. The ratio of theoretical and actual costs is expressed by the value of the volumetric efficiency:
However, in modern pumps, due to the reliable sealing of pipelines and connections, the actual performance is the same as the theoretical one. In most cases, the pump is selected for a specific piping system, and the flow rate is set in advance.
Head is the energy imparted by the pump to the pumped medium, related to the mass unit of the pumped medium. It is denoted by the letter H and has the dimension of meters. It should be clarified that the pressure is not a geometric characteristic and is not the height to which the pump can lift the pumped medium.
Power consumption(power on the shaft) - the power consumed by the pump during operation. The consumed power differs from the useful power of the pump, which is spent directly on the communication of energy to the pumped medium. Part of the power input can be lost due to leakage, friction in bearings, etc. The efficiency factor determines the ratio between these quantities.
For various types pumps, the calculation of these characteristics may differ, due to differences in their design and principles of operation.
Performance calculation for various pumps
The whole variety of types of pumps can be divided into two main groups, the calculation of the performance of which has fundamental differences. According to the principle of operation, pumps are divided into dynamic and volumetric. In the first case, the pumping of the medium occurs due to the impact of dynamic forces on it, and in the second case, due to a change in the volume of the working chamber of the pump.
Dynamic pumps include:
1) Friction pumps (vortex, screw, disk, jet, etc.)
2) Vane (axial, centrifugal)
3) Electromagnetic
Positive displacement pumps include:
1) Reciprocating (piston and plunger, diaphragm)
2) rotary
3) Vane
Below are formulas for calculating performance for the most common types.
The main working element of a piston pump is a cylinder in which the piston moves. The piston performs reciprocating movements due to the crank mechanism, which ensures a consistent change in the volume of the working chamber. For one complete revolution of the crank from the extreme position, the piston makes full speed forward (discharge) and backward (suction). When pumping, an excess pressure is created in the cylinder by the piston, under the action of which the suction valve closes, and the discharge valve opens, and the pumped liquid is supplied to the discharge pipeline. During suction, the reverse process takes place, in which a vacuum is created in the cylinder due to the piston moving back, the discharge valve closes, preventing the backflow of the pumped medium, and the suction valve opens and the cylinder is filled through it. The actual performance of piston pumps is somewhat different from the theoretical one, which is due to a number of factors, such as fluid leakage, degassing of gases dissolved in the pumped liquid, delays in opening and closing valves, etc.
For piston pump simple action The expense formula will look like this:
Q = F S n η V
Q - flow rate (m 3 / s)
S - piston stroke length, m
For a double-acting piston pump, the performance calculation formula will be slightly different, due to the presence of a piston rod that reduces the volume of one of the working chambers of the cylinder.
Q = F S n + (F-f) S n = (2F-f) S n
Q - flow rate, m 3 / s
F - piston cross-sectional area, m 2
f - cross-sectional area of the rod, m 2
S - piston stroke length, m
n - shaft rotation frequency, sec -1
η V – volumetric efficiency
If we neglect the rod volume, then the general formula for the performance of a piston pump will look like this:
Q = N F S n η V
Where N is the number of actions performed by the pump in one revolution of the shaft.
In the case of gear pumps, the role of the working chamber is performed by the space limited by two adjacent gear teeth. Two gears with external or internal gearing are placed in the housing. The suction of the pumped medium into the pump occurs due to the vacuum created between the teeth of the gears that come out of engagement. Fluid is carried by the teeth in the pump housing and then squeezed out into the discharge port at the moment the teeth re-engage. For the flow of the pumped medium in gear pumps, end and radial clearances between the housing and gears are provided.
The performance of a gear pump can be calculated as follows:
Q = 2 f z n b η V
f - cross-sectional area of the space between adjacent gear teeth, m 2
z - number of gear teeth
b - gear tooth length, m
n - frequency of rotation of the teeth, sec -1
η V – volumetric efficiency
There is also an alternative formula for calculating the performance of a gear pump:
Q = 2 π D H m b n η V
Q - gear pump performance, m 3 / s
D H - the initial diameter of the gear, m
m – gear module, m
b – gear width, m
n - gear rotation frequency, sec -1
η V – volumetric efficiency
In pumps of this type, pumping of the medium is ensured by the operation of a screw (single-screw pump) or several screws that are engaged in the case of multi-screw pumps. The profile of the screws is selected in such a way that the pump discharge area is isolated from the suction area. The screws are located in the housing in such a way that during their operation areas filled with the pumped medium are formed closed space, limited by the profile of the screws and the body and moving in the direction in the injection area.
The performance of a single screw pump can be calculated as follows:
Q = 4 e D T n η V
Q - productivity of the screw pump, m 3 / s
e – eccentricity, m
D is the diameter of the rotor screw, m
T - step of the helical surface of the stator, m
n - rotor speed, sec -1
η V – volumetric efficiency
Centrifugal pumps are one of the most numerous representatives of dynamic pumps and are widely used. The working body in centrifugal pumps is a wheel mounted on a shaft, having blades enclosed between disks, and located inside a spiral housing.
Due to the rotation of the wheel, a centrifugal force is created that acts on the mass of the pumped medium inside the wheel and transfers to it a part of the kinetic energy, which then turns into the potential energy of the head. The vacuum created in this case in the wheel ensures a continuous supply of the pumped medium from the suction pipe. It is important to note that the centrifugal pump must be pre-filled with the pumped medium before starting operation, otherwise the suction force will not be sufficient for the normal operation of the pump.
A centrifugal pump may have more than one working body, but several. In this case, the pump is called multistage. Structurally, it differs in that several impellers are located on its shaft at once, and the liquid sequentially passes through each of them. A multistage pump with the same capacity will create more pressure compared to a similar single-stage pump.
The performance of a centrifugal pump can be calculated as follows:
Q \u003d b 1 (π D 1 -δ Z) c 1 \u003d b 2 (π D 2 -δ Z) c 2
Q - performance of a centrifugal pump, m 3 / s
b 1.2 - wheel passage widths on diameters D 1 and D 2, m
D 1.2 - outer diameter of the inlet (1) and outer diameter of the wheel (2), m
δ – blade thickness, m
Z - number of blades
C 1,2 - radial components of absolute velocities at the entrance to the wheel (1) and exit from it (2), m/s
Head calculation
As noted above, the pressure is not a geometric characteristic and cannot be identified with the height to which it is necessary to raise the pumped liquid. The required pressure value is made up of several terms, each of which has its own physical meaning.
The general formula for calculating the pressure (the diameters of the suction and discharge pipes are assumed to be the same):
H \u003d (p 2 -p 1) / (ρ g) + H g + h p
H - head, m
p 1 - pressure in the intake tank, Pa
p 2 - pressure in the receiving tank, Pa
H g - geometric height of the pumped medium, m
h p - total pressure loss, m
The first term in the formula for calculating the pressure is the pressure drop that must be overcome in the process of pumping liquid. There are cases when the pressures p 1 and p 2 coincide, while the pressure created by the pump will go to raise the liquid to a certain height and overcome the resistance.
The second term reflects the geometric height to which it is necessary to raise the pumped liquid. It is important to note that when determining this value, the geometry of the pressure pipeline, which can have several ups and downs, is not taken into account.
The third term characterizes the decrease in the generated pressure, which depends on the characteristics of the pipeline through which the medium is pumped. Real pipelines will inevitably resist the flow of liquid, to overcome which it is necessary to have a margin of pressure. The total resistance is the sum of friction losses in the pipeline and losses in local resistances, such as pipe bends and bends, valves, expansion and narrowing of the passage, etc. The total pressure loss in the pipeline is calculated by the formula:
H vol - total pressure loss, consisting of friction losses in pipes H t and losses in local resistances N ms
H about \u003d H T + H MS \u003d (λ l) / d e + ∑ζ MS \u003d ((λ l) / d e + ∑ζ MS)
λ – coefficient of friction
l - pipeline length, m
d E - equivalent diameter of the pipeline, m
w is the flow velocity, m/s
g - free fall acceleration, m / s 2
w 2 /(2 g) - velocity head, m
∑ζ MS - the sum of all coefficients of local resistance
Calculation of pump power input
Several powers are allocated depending on the losses during its transmission, which are taken into account various coefficients useful action. The power going directly to the energy transfer of the pumped liquid is calculated by the formula:
N П = ρ·g·Q·H
N P - useful power, W
ρ - density of the pumped medium, kg / m 3
g - free fall acceleration, m / s 2
Q - flow rate, m 3 / s
H - total head, m
The power developed on the pump shaft is more useful, and its excess is used to compensate for power losses in the pump. The relationship between net power and shaft power is established by the efficiency of the pump. pump efficiency takes into account leaks through seals and gaps (volumetric efficiency), head losses due to the movement of the pumped medium inside the pump (hydraulic efficiency) and friction losses between moving parts of the pump, such as bearings and seals (mechanical efficiency).
N B \u003d N P / η N
N V - power on the pump shaft, W
N P - useful power, W
η H - pump efficiency
In turn, the power developed by the motor exceeds the power on the shaft, which is necessary to compensate for energy losses during its transfer from the motor to the pump. The power of the electric motor and the power on the shaft are related by the efficiency of the transmission and the motor.
N D \u003d N B / (η P η D)
N D - power consumption of the engine, W
N V - shaft power, W
η P - transmission efficiency
η H - engine efficiency
The final installed motor power is calculated from the motor power, taking into account possible overload at the time of starting.
N Y - installed power of the engine, W
N D - power consumption of the engine, W
β –
power factor
The power factor can be approximately selected from the table:
Suction lift limit
(for centrifugal pump)
Suction in a centrifugal pump occurs due to the pressure difference in the vessel, from which the pumped medium is taken from, and on the impeller blades. An excessive increase in the pressure difference can lead to cavitation - a process in which the pressure drops to a value at which the boiling point of the liquid drops below the temperature of the pumped medium and its evaporation begins in the flow space with the formation of many bubbles. The bubbles are carried away by the flow further downstream, where, under the influence of increasing pressure, they condense and “collapse”, accompanied by numerous hydraulic shocks, which negatively affect the life of the pump. In order to avoid the negative effects of cavitation, it is necessary to limit the suction lift of the centrifugal pump.
The geometric suction lift can be determined by the formula:
h g \u003d (P 0 -P 1) / (ρ g) - h sv - w² / (2 g) - σ H
h G - geometric suction height, m
P 0 - pressure in the intake tank, Pa
P 1 - pressure on the blades of the impeller, Pa
ρ - density of the pumped medium, kg / m 3
g - free fall acceleration, m / s 2
h sv - losses to overcome hydraulic resistance in the suction pipeline, m
w²/(2 g) – velocity head in the suction pipeline, m
σ H – additional resistance loss proportional to head, m
where σ is the cavitation coefficient, H is the pressure created by the pump
The cavitation coefficient can be calculated using the empirical formula:
σ = [(n √Q) / (126H 4/3)] 4/3
σ – cavitation coefficient
n - impeller speed, sec -1
Q - pump performance, m 3 / s
H - created pressure, m
There is also a formula for centrifugal pumps to calculate the head margin to ensure the absence of cavitation:
H sq \u003d 0.3 (Q n²) 2/3
H sq - head reserve, m
Q - performance of a centrifugal pump, m 3 / s
n - impeller speed, s -1
Examples of tasks for the calculation and selection of pumps with solutions
Example #1
The single-acting plunger pump provides a flow rate of the pumped medium of 1 m 3 / h. The plunger diameter is 10 cm, and the stroke length is 24 cm. The rotational speed of the working shaft is 40 rpm.
It is required to find the volumetric efficiency of the pump.
Plunger cross-sectional area:
F = (π d²)/4 = (3.14 0.1²)/4 = 0.00785 m²2
We express the efficiency from the plunger pump flow formula:
η V = Q/(F S n) = 1/(0.00785 0.24 40) 60/3600 = 0.88
Example #2
The double-acting double-piston pump generates a head of 160 m when pumping oil with a density of 920 kg/m 3 . The piston diameter is 8 cm, the rod diameter is 1 cm, and the piston stroke is 16 cm. The rotational speed of the working shaft is 85 rpm. Need to calculate required power electric motor (the efficiency of the pump and the electric motor is taken to be 0.95, and the installation factor is 1.1).
Piston and rod cross-sectional areas:
F \u003d (3.14 0.08²) / 4 \u003d 0.005024 m²
F \u003d (3.14 0.01²) / 4 \u003d 0.0000785 m²
The pump performance is found by the formula:
Q = N (2F-f) S n = 2 (2 0.005024-0.0000785) 0.16 85/60 = 0.0045195 m³/h
N P \u003d 920 9.81 0.0045195 160 \u003d 6526.3 W
Taking into account the efficiency and the installation factor, we obtain the final installed power:
N SET \u003d 6526.3 / (0.95 0.95) 1.1 \u003d 7954.5 W \u003d 7.95 kW
Example #3
A three-piston pump pumps a liquid with a density of 1080 kg/m 3 from an open container into a pressure vessel of 1.6 bar at a flow rate of 2.2 m 3 /hour. The geometric height of the liquid rise is 3.2 meters. The useful power consumed for pumping liquid is 4 kW. It is necessary to find the magnitude of the pressure loss.
Let's find the pressure created by the pump from the formula for useful power:
H \u003d N P / (ρ g Q) \u003d 4000 / (1080 9.81 2.2) 3600 \u003d 617.8 m
We substitute the found value of the head into the head formula, expressed in terms of the pressure difference, and find the desired value:
h p \u003d H - (p 2 -p 1) / (ρ g) - H g \u003d 617.8 - ((1.6-1) 10 5) / (1080 9.81) - 3.2 = 69.6 m
Example #4
The actual productivity of the screw pump is 1.6 m 3 /hour. Geometric characteristics of the pump: eccentricity - 2 cm; rotor diameter - 7 cm; the pitch of the helical surface of the rotor is 14 cm. The rotor speed is 15 rpm. It is necessary to determine the volumetric efficiency of the pump.
We express the desired value from the screw pump performance formula:
η V = Q/(4 e D T n) = 1.6/(4 0.02 0.07 0.14 15) 60/3600 = 0.85
Example #5
It is necessary to calculate the head, flow rate and useful power of a centrifugal pump pumping a liquid (low viscosity) with a density of 1020 kg / m 3 from a tank with overpressure 1.2 bar and a tank with an overpressure of 2.5 bar through a given pipeline with a pipe diameter of 20 cm. The total length of the pipeline (total with the equivalent length of local resistances) is 78 meters (take the coefficient of friction equal to 0.032). The height difference of the tanks is 8 meters.
For low-viscosity media, we choose the optimal speed of movement in the pipeline equal to 2 m/s. Calculate the fluid flow through a given pipeline:
Q \u003d (π d²) / 4 w \u003d (3.14 0.2²) / 4 2 \u003d 0.0628 m³ / s
Velocity head in the pipe:
w²/(2 g) = 2²/(2 9.81) = 0.204 m
With an appropriate velocity head, friction losses and local resistances will be:
H T \u003d (λ l) / d e \u003d (0.032 78) / 0.2 0.204 \u003d 2.54 m
The total pressure will be:
H \u003d (p 2 -p 1) / (ρ g) + H g + h p \u003d ((2.5-1.2) 10 5) / (1020 9.81) + 8 + 2.54 = 23.53 m
It remains to determine the useful power:
N P \u003d ρ g Q H \u003d 1020 9.81 0.0628 23.53 \u003d 14786 W
Example #6
Is it advisable to pump water with a centrifugal pump with a capacity of 50 m 3 / hour through a 150x4.5 mm pipeline?
Calculate the flow rate of water in the pipeline:
Q = (π d²)/4 w
w \u003d (4 Q) / (π d²) \u003d (4 50) / (3.14 0.141²) 1/3600 \u003d 0.89 m / s
For water, the flow velocity in the discharge pipeline is 1.5 - 3 m/s. The resulting value of the flow rate does not fall within this interval, from which we can conclude that the use of this centrifugal pump is impractical.
Example #7
Determine the feed rate of the gear pump. Geometric characteristics of the pump: cross-sectional area of the space between the gear teeth 720 mm 2 ; number of teeth 10; gear tooth length 38 mm. The rotational speed is 280 rpm. The actual flow of the gear pump is 1.8 m3/h.
Theoretical pump performance:
Q \u003d 2 f z n b \u003d 2 720 10 0.38 280 1 / (3600 10 6) \u003d 0.0004256 m³ / h
The feed rate is respectively equal to:
ηV = 0.0004256/1.8 3600 = 0.85
Example #8
A pump with an efficiency of 0.78 pumps liquid with a density of 1030 kg/m 3 at a flow rate of 132 m 3 /hour. The pressure created in the pipeline is 17.2 m. The pump is driven by an electric motor with a power of 9.5 kW and an efficiency of 0.95. It is necessary to determine if the pump meets the requirements for starting torque.
Calculate the useful power that goes directly to pumping the medium:
N P \u003d ρ g Q H \u003d 1030 9.81 132 / 3600 17.2 \u003d 6372 W
We take into account the efficiency of the pump and the electric motor and determine the total required power of the electric motor:
N D \u003d N P / (η N η D) \u003d 6372 / (0.78 0.95) \u003d 8599 W
Since we know the installed power of the motor, we determine the power factor of the electric motor:
β \u003d N Y / N D \u003d 9500/8599 \u003d 1.105
For engines with a power of 5 to 50 kW, it is recommended to tear out the starting power reserve from 1.2 to 1.15. The value obtained by us does not fall into this interval, from which we can conclude that during the operation of this pump under the given conditions, problems may arise at the time of its start-up.
Example #9
A centrifugal pump pumps a liquid with a density of 1130 kg/m 3 from an open tank into a reactor with an operating pressure of 1.5 bar at a flow rate of 5.6 m 3 /hour. The geometric height difference is 12 m, with the reactor located below the tank. The pressure loss due to friction in the pipes and local resistance is 32.6 m. It is required to determine the useful power of the pump.
Calculate the pressure created by the pump in the pipeline:
H \u003d (p 2 -p 1) / (ρ g) + H g + h p \u003d ((1.5-1) 10 5) / (1130 9.81) - 12 + 32.6 \u003d 25 .11 m
The useful power of the pump can be found by the formula:
N P \u003d ρ g Q H \u003d 1130 9.81 5.6 / 3600 25.11 \u003d 433 W
Example #10
Determine the maximum increase in the flow rate of a pump pumping water (take the density equal to 1000 kg / m 3) from an open tank to another open tank with a flow rate of 24 m3 / h. The geometric height of the liquid is 5 m. Water is pumped through pipes 40x5 mm. The power of the electric motor is 1 kW. The overall efficiency of the installation is taken equal to 0.83. The total pressure loss due to friction in pipes and in local resistances is 9.7 m.
Let us determine the maximum flow rate corresponding to the maximum possible useful power developed by the pump. To do this, we first define several intermediate parameters.
Calculate the pressure required to pump water:
H \u003d (p 2 -p 1) / (ρ g) + H g + h p \u003d ((1-1) 10 5) / (1000 9.81) + 5 + 9.7 \u003d 14.7 m
Useful power developed by the pump:
N P \u003d N total / η H \u003d 1000 / 0.83 \u003d 1205 W
Meaning maximum flow find from the formula:
N П = ρ·g·Q·H
Let's find the desired value:
Q max \u003d N P / (ρ g H) \u003d 1205 / (1000 9.81 14.7) \u003d 0.00836 m³ / s
The water flow can be increased by a maximum of 1.254 times without violating the requirements for pump operation.
Q max / Q \u003d 0.00836 / 24 3600 \u003d 1.254
The scope of industrial pumping equipment is very wide. In fact, the industrial pump is used in any industrial area where it is necessary to transport liquid, bulk and viscous materials over long distances. Therefore, such an installation is in demand in the oil, chemical, food, machine-building fields of production, as well as in agriculture.
Industrial pumps differ from household options in higher performance, and as a result, in design solutions. The specifics of each individual type of equipment depends on individual conditions using the unit.
1 Types of industrial pumps
Various manufacturers supply the market with a huge number of variations of pumps and pumping equipment. And if there are no problems when buying an industrial water pump, then the search for a device to work with chemicals and dense fractions can become an impossible task. After all, highly specialized industrial pumps are practically not produced, and universal models are not always suitable for each specific type of pumped substance.
In this regard, much depends on the scope of the device and the main design aspects of the model. Based on these two characteristics, the following types of industrial pumps are distinguished:
- centrifugal;
- gear;
- screw;
- barrel;
- diaphragmatic.
1.1 Features of centrifugal industrial plants
Industrial centrifugal pumps are mainly used for pumping cold or hot water inside thermal and water mains. The same principle is used during operation of industrial drainage pumps, with the help of which water disposal is carried out from pits, mines and open reservoirs. This segment of the units is most often used in production, and industrial high-pressure pumps also function on its basis.
The basis for such units is the working chamber, in which a wheel with an impeller is welded onto the rotor. When power is supplied to the electric pump, the motor drives the rotor. Together with the shaft, the impeller begins to rotate. In this case, the blades take the liquid, and begin to rotate it in a circle at high speed. As a result, under the action of centrifugal force, a region of rarefied air is formed at the inlet of the device, and water is sucked in; high pressure and pressure is created.
This design has a standard centrifugal pump. There are also modified versions of the devices. So, according to the type of working body, water pumps of this type are divided into:
- single-stage with one impeller;
- two-stage with two wheels and two diffusers;
- multi-stage with several wheels.
More wheels provide greater performance models, at the same time, electricity consumption increases.
Regarding the design of the impeller, centrifugal options with a closed and open impeller are distinguished. Also, the distribution is carried out in terms of supplying liquid to the working chamber. In this case, devices with a one-sided inlet and a two-sided start are distinguished.
The scope of the model also depends on the design of the shaft and its location. Industrial models with a horizontal rotor orientation are mainly installed in pumps for water supply. Such embodiments provide a fluid flow rate from 50 to 270 cubic meters. m/h and head up to 100 m.
A vertically oriented shaft is mounted, as a rule, in drainage pumps for water. Industrial submersible pumps of this type are used for pumping heavily polluted sources. They are made of steel or reinforced cast iron. At the same time, the design of the impeller and powerful engine allow the passage of liquid containing solids, with a diameter of more than 100 mm. At the same time, the average productivity for such units is over 50 cubic meters. m/hour.
1.2 Design and principle of operation of gear devices
With the help of industrial pumps and units of this type, both liquid and viscous high-temperature substances are transported. Such a pump consists of two or more gears, which are located inside the working chamber. One of the gears is the leading one. It is mounted on a shaft coming from the motor. The second gear is the driven gear. It is mounted on a metal rod with the help of a bushing and is driven by the leader. The opening between the working compartment and the engine is hermetically sealed with graphite seals.
The principle of operation of such a device is as follows:
- the wheels rotate in different directions, up from the inlet;
- with the help of teeth (straight, oblique or chevron), water is taken from a tasty pipe and transported upward in the resulting closed cavities;
- in the area of the discharge pipe, as a result of constant supply, a high pressure is formed and, as a result, the supply of liquid to the pipeline.
As a result of the operation of such gears, a continuous supply of fluid is formed. The only disadvantage of such devices is their increased sensitivity to solid impurities that harm the nodes.
An overview of the main performance data includes the following values:
- capacity from 60 to 380 cu. m/hour;
- the temperature of the pumped medium is from -40 to +480 degrees;
- viscosity up to 1,000,000 cSt.
1.3 Screw industrial units
Screw devices are used for various industries. They are used in mining, engineering, oil refining, food industries. Many pumps for the chemical industry are built on the same principle of operation.
Among the main advantages that distinguish such a pump are a high pressure characteristic, continuity of supply. Also, with the help of such devices, it is possible to work with thick substances, as well as with liquids containing a high percentage of abrasive impurities.
As a rule, screw units have a cylindrical design. The basis of such devices is a metal screw, which rotates from the engine and a rubber stator. During rotation, the rotor spiral comes into contact with the stator surface, forming temporary sealed chambers. It is in these chambers that the pumped medium is transported to the outlet.
In terms of use, screw pumps and equipment are divided into horizontal and vertical. Horizontal ones are more designed to work with thick materials. They are installed on anti-vibration pads or a special base. By using vertical options mineral and salt water is extracted from wells. This segment is represented by industrial deep pumps for deep sources.
The screw pump, submersible and surface version, is capable of providing fluid flow in the range from 50 to 1700 cubic meters. m/hour. The device is suitable for working with liquids, the temperature of which reaches 180 degrees. The working pressure of the apparatus is 24 bar.
A wide range of screw industrial pumping equipment is also produced in Russia. The main Russian supplier of screw units is AMC. Also popular brands in the Russian Federation are ENCE engineering, VIP Technology, LAKKK.
1.4 Barrel pumping devices
Barrel aggregates are mainly used in the chemical industry. With the help of such devices, alkali, acids and other aggressive substances are pumped. The main task such models is pumping liquid from one tank to another, or cleaning individual tanks. A wide range of such devices allows the selection of equipment for each type of source.
Devices of this type are made of chemically neutral polymer compositions or alloy steel. In most cases, they are compact in size for more easy installation pumping equipment.
Separate models of barrel pumps are made in explosion-proof cases. At the same time, the transition from the engine to the working chamber is protected by a special magnetic coupling, which seals the engine compartment as tightly as possible.
In terms of the execution of the working body, barrel pumps are:
2 Characteristics of industrial diaphragm pumps
Diaphragm devices belong to the volumetric type of devices. According to the principle of operation, such units are similar to piston devices. The difference is that instead of a piston, a flexible membrane is used here.
During the operation of the engine, it moves a metal rod, on the edge of which a diaphragm is fixed. When the diaphragm flexes, a vacuum is formed in the working chamber, due to which liquid is sucked through the pump nozzle. At the next phase of the membrane movement, it returns to its original position, due to which the fluid is pushed into the pipeline.
Many industrial pumps are made in the form of two-chamber devices. In this case, the engine sets in motion two, oppositely placed, chambers at once. At the same time, the moving membrane complements the other, providing a more even flow and high performance. The main materials from which membrane devices are made are plastic, cast iron, steel or aluminum-based alloys.
The main advantages of diaphragm industrial models are versatility and performance. Such a device is suitable for all types of substances: aggressive chemicals, thick, materials with a high content of solid suspension. Also, the features of the type include simplicity of design, which facilitates the repair of pumping equipment.
2.1 Calpeda pumping equipment (video)
The official PedrolloPasos online store offers low prices for Pedrollo pumps for wells, wells and septic tanks. In assortment - more than ten categories of equipment Italian manufacturer, available for shipment from a warehouse in Moscow. The products are certified and meet international and Russian standards.
Before you buy a Pedrollo pump, you can familiarize yourself with the full technical characteristics of the product on the website or get qualified advice from a manager. We will answer your questions and select the optimal equipment package. If necessary, you can order components and accessories for any model.
Catalog:
Over ten years on the market - thousands of customers across the country
The main activity of the company is retail supplies of equipment. You can buy a Pedrollo pump in Moscow from any city in Russia. Own transport service and cooperation with leading carrier companies allows us to ship orders to all regions. Call our managers to discuss all questions on the delivery of goods.
Why is it profitable with us? It is worth buying Pedrollo pumps in Moscow in our online store for several reasons:
- The company sells equipment as an official dealer. This means that you receive not only complete information and technical support, but also warranty service, as well as the ability to order original spare parts for repairs.
- Low prices. The status of a dealer allows the company to set favorable prices for buyers. Pedrollo pumps for water and other liquids are cheaper than in many retail stores. The cost of production is transparent - the final prices for products are indicated in the price list. You can find the price list on our website.
- Wide range of products. The catalog contains all the products of the manufacturer in a complete set. In addition to the main equipment, the company supplies engines, electronic pressure regulators, and other components. Always available - Pedrollo deep pumps, which are in great demand.
Among the advantages of the company can be attributed to its extensive experience in the market. We have been working for more than ten years, during this time we have concluded supply contracts with thousands of customers from different regions. We cooperate with private clients, enterprises, municipal organizations, representatives of agriculture.
To buy a Pedrollo pump in Moscow, you can visit specialized exhibitions - we regularly participate in such events. This gives additional experience to both the company itself and its employees.
Call us or place an order on the website - all equipment from the catalog is in stock and ready to ship, and the price of the Pedrollo pump will always be favorable.
The technical characteristics of industrial units are not comparable with the power of household pumping equipment, and this is natural. General classification includes at least seventy types and subspecies of pumps.
Which of them are capable of developing such a capacity to satisfy the needs of large-scale production, or to provide water supply to a metropolis? And in general, what are industrial high-pressure pumps?
The instructions we have proposed will tell about this, as well as the video in this article.
What units for water are used in production
The technological processes of many industries, one way or another, are associated with water or other liquids that also need to be pumped.
Much, if not all, depends on the reliability of the pumping equipment involved in the work. Therefore, its choice is carried out according to the calculation and actual operating conditions.
- Note that in our country there are many enterprises specializing in the manufacture of industrial units. In many industries and industries, domestic equipment is used, and this has many advantages. Firstly, in terms of quality, they are in no way inferior to imported counterparts.
- Secondly, the price of any product produced in its own country is always lower, as transport costs are reduced. And yet, in the event of a breakdown, you can easily order and deliver a replacement spare part (see), or, if necessary, invite a competent representative from the factory.
- Only Chinese-made pumps can compete with domestic equipment in terms of cost, but there is no particular confidence in their quality. So, characterizing industrial high-pressure pumps - at least in terms of markings and symbols, we will rely on the standards adopted in our country.
- All existing pumps, according to the type of the working chamber, as well as its communication with the input and output, are divided into two groups: volumetric and dynamic. In volumetric aggregates, the movement of fluid is ensured by periodically changing the volume of the chamber - hence the name. That is, the mechanism of such a pump is based on reciprocating motion.
- We will not talk about this equipment in more detail, since it is not used for water. Almost all volumetric pumps are industrial, but their main purpose is pumping viscous liquids. They are used in the oil and pharmaceutical industries, in some food and chemical industries.
As for dynamic equipment, its principle of operation is based on the conversion of one type of energy into another. For water it is perfect option: due to the number of working bodies and the speed of their rotation, as well as the layout of several pumps, you can create a unit of arbitrarily large power.
Axial pumps
The group is divided into three subgroups, in each of which different forces act on the fluid. Among them are electromagnetic pumping equipment, friction pumps, and vane pumps.
It is the last subgroup that includes axial units, which are most often manufactured in an industrial version.
- They can have rigidly fixed blades, or they can be rotary-bladed. Regardless of this, the water in the chamber moves in the direction of its axis, which is the main feature of axial pumps. By the way, in pumps with rotary vanes, due to the possibility of changing the angle of their installation, it is possible to more extensively adjust the performance and pressure.
- Such pumps are marked "O" and "OP". IN powerful units for industrial use, water is discharged from the working chamber at an angle of 60 degrees, while in small pumps, the angle of discharge is straight. Rotary units have one more feature: the pump shaft is hollow, and inside it there is a rod that fixes the mechanism for the movement of the blades.
- This mechanism can be operated manually, hydraulically or electrically. We think it is unnecessary to say that the change in the position of the blades is carried out only if the pump is turned off. Axial pumps are usually designed for high flow at low head. Imagine that their productivity can exceed 120,000 m3/h!
- Units with an axial design compare favorably with centrifugal equipment in that they can pump not only clean water, but also liquids with a certain degree of contamination. There is another advantage: with a similar speed factor, taking into account three main parameters (pressure, flow, wheel speed), the dimensions and weight of the pump will be smaller.
- Axial pumps are used where high pressure is not needed, but a significant water flow is expected. In water supply systems, these are the stations of the first lift, in melioration - irrigation installations. They are also used in sewers and drainage systems, treatment facilities, in construction dewatering.
- According to the type of casing, axial pumps can be vertical (OV), horizontal, capsule type, and submersible. Vertical units, including rotary ones (OPV), are used at nuclear and thermal power plants, in agriculture, as well as for pumping sea water.
- Large capacity pumps most often have an axial inlet. At the same time, the working chamber and the engine of the unit, although they are in the same plane, are installed on different foundations. As a rule, all fecal pumps do this - and this applies to both vertical and horizontal modifications.
As for submersible models, they are usually monoblock. That is, both the working chamber and the motor, although not always located in a common housing, are a single unit. You can see this version of the pump in the photo above.
Centrifugal units on an industrial scale
They also apply to paddle equipment, and differ from the previous version only in the direction of water movement.
In this case, it does not move at an angle to the wheel axis, but along it. Moreover, the shaft rotates in one direction, and the ring of water - in the other.
- This principle of operation allows you to significantly increase the water pressure, especially in those models that have a multi-stage design. Therefore, centrifugal pumps are used where it is required to create high pressure in the pipeline. First of all, these are stations of the second and subsequent lifts - in water supply, sewerage and fire extinguishing systems. Also, this circulation pumps for heating systems.
- According to the type of housing, centrifugal pumps are also vertical and horizontal, and can be surface and submersible. Two more categories should be distinguished. These are models for Wastewater, and the so-called soil pumps, which are used for pumping slurries.
- The last option differs from the rest of the units in the version of the entrance: it can be axial or lateral. Distinctive feature ground and is the fact that they are all equipped with a flushing system that allows you to eliminate blockages.
- These pumps have big power, and are capable of not only lifting liquefied soil, for example, from a deep mine, but also transporting it over quite considerable distances. Such operating conditions of the equipment are not at all the same as the supply pure water from the well. Therefore, in the manufacture of working parts and seals for these pumps, the most strong metals and alloys, composites and reinforced rubber.
Soil, sand and are used in the mining and processing industry, in the development of oil fields, drilling of deep artesian wells, in some industries, in construction. They are designed for high content abrasive impurities in water, and this figure can reach more than 1200 kg per 1 m3 of water.
Features of installing industrial pumps
As you can see, and specifications, and operating conditions, pumping equipment is completely different. Therefore, it is simply impossible to generalize the installation process and commissioning of an industrial pump. But there is certainly something in common.
All units are delivered to the consumer assembled, complete with a control cabinet, instrumentation and connecting fittings. Before installation, electricians and mechanics can only inspect for compliance with the declared configuration and check the operation of the mechanism.
Foundation for the unit
Depending on the dimensions and purpose of the pump, a special foundation is placed under it, reinforced concrete slab, or a frame is welded from a steel channel.
As for the frame, in agreement with the customer, it can be supplied by the factory together with the unit.
- Attach such a frame to monolithic foundation, poured specifically for this purpose. And, by the way, the process of producing these works must comply with building codes. In this case, this is SNiP 2.02.05 * 87 - it regulates the construction of foundations for machines that create dynamic loads. Pumping units also belong to their category.
- In the process of pouring the foundation, anchor bolts are embedded in the thickness of the concrete, with the help of which the metal support for the unit is rigidly fixed. Anchors can be up to 70cm long and usually come with the frame if it is factory made.
- When the pump is not monoblock, there are regular places on the frame designed to install the pump itself and its engine. As mentioned earlier, there are options for pumps, the engine of which must be installed on a separate frame. Then, respectively, two foundations are built.
- After the frame is installed, the correctness of its position is verified using a level. After that, the anchor bolts located in the well-shaped holes are tightened, and then they are poured with concrete. Such fastening gives a 100% guarantee that it will not be weakened over time.
Then they proceed to install the engine and pump, also leveling their spatial position, after which they align their shafts. As a protection against oil ingress, the concrete foundation is primed with liquid cement mortar with the addition of red lead, and then, just like the frame, they paint.
The introduction of the pump into the plumbing system
A pump, or an installation that combines several pumps into one enlarged unit, is located in a specially designated capital room or pavilion.
It depends on the purpose of the equipment and on the dimensions:
- If it's tap water or heating system, the installation site can be a boiler room, a heating point, or a boiler room. For example, in production, the pump must be installed directly in the workshop where water supply is required. In this case, a fence is simply installed around the perimeter of the pump foundation, which must have a height of at least 20 cm.
- Since people work in the workshops, measures must be taken to soundproof the unit. In particular, it is necessary to reduce, and it is better to reduce vibration to zero altogether. It is known that it is capable of destroying any, even the most reliable mechanism. Usually these problems are solved with the help of shock-absorbing mounts for equipment, and special flexible inserts for pipelines.
- After graduation installation work, including the laying of pipelines, the system is tested and accepted, which is formalized by the relevant act. First, a hydraulic test is performed, and then a pneumatic test to detect defects made during installation.
At the same time, plugs (inventory plugs) must be installed at the ends of the pipelines. IN circulation systems the uniformity of heating of all elements of the pipeline is checked. And only after successful tests, the plugs are removed, and the pressure pipeline is inserted into the manifold.
The characteristics of the pump is usually understood as the relationship of the technical indicators of the unit - pressure, power, efficiency, pressure, flow and suction height at different conditions work. This takes into account the speed of the impeller, the consistency of the pumped liquid at the inlet and outlet.
The characteristic of a centrifugal pump depends on its design, the materials from which the parts are made, and also on the principle of operation of the main components.
The most accurate characteristics of the pump are determined experimentally in the factory. It happens that the characteristics are indicated theoretically based on the calculations, but in this case, the real data may differ from the expected ones. The operation of centrifugal pumps takes into account a large number of external factors that are not always possible to foresee, therefore, the characteristics obtained theoretically have a certain percentage of inaccuracy.
Tests that reveal the characteristics of a centrifugal pump are carried out in accordance with the state standard. In this case, the pump is equipped with measuring instruments that record the readings of the unit during start-up. In our catalog, industrial pumps for water are presented in a wide range.
In the documentation for a centrifugal pump, the characteristic is usually presented in the form of a graph with several curves and is indicated next to technical parameters. On such graphs, you can trace the dependence of suction height on flow, pressure on power, efficiency on pressure and get acquainted with other characteristics. The centrifugal cantilever pump is designed for stationary pumping of clean water (except for sea water) with pH=6-9.
The principle of operation of centrifugal pumps
The operation of centrifugal pumps is possible only if the body of the device is filled with water. As the name implies, these pumps operate under the action of centrifugal force caused by rotating wheels.
The pump housing contains one or more impellers firmly fixed on the shaft. The impeller is equipped with curved vanes, where the liquid flows through the suction pipe. When the unit is started, the shaft connected to the electric motor drives the wheel, which captures the liquid with the blades and throws it away from the center to the inner walls of the housing. The developed centrifugal force moves the liquid to the discharge pipeline through the guide chamber. Thus, with the release of the space between the blades, the pressure is reduced, which makes it possible to receive newly incoming liquid from the suction pipeline. As a rule, the suction pipe is equipped with a filter element that prevents solid particles and debris from entering the housing.
Depending on the number of impellers, centrifugal pumps can be of a single-stage or multi-stage design, but the principle of their operation remains almost the same. The difference is that in multi-stage units, the fluid pressure increases at each subsequent wheel.
Multipumps Group of Companies offers a wide range of pumping equipment.
