Flexible bellows water connection 1 2. Flexible bellows water connection - corrugated stainless steel. Flexible hose for the mixer: Design features.

Today, it is practically impossible to do without a flexible connection when communicating plumbing.

The reliability of the system as a whole largely depends on the correct choice of eyeliner.

One of the best offers on the market was a bellows flexible hose made of of stainless steel.

What is it and where does it apply

Flexible eyeliner is a product made of a flexible elastic material that can replace a pipeline section in places where the installation of conventional structures (pipes with fittings) is difficult or impossible.

Tightening rods prevent twisting of the joint and exclude axial loads until the connection is compressed. Studs are added to these connectors at the factory. Thermal expansion contraction knobs Excellent for high temperature applications Can be designed for higher pressure applications Ideal for applications with many chemicals other than those that are highly corrosive. Relatively stiff Poor lateral movement More expensive Poor noise and vibration quality. They are usually available in two, three, or five rolls and are limited to more than high pressures.

Such products are in demand for:

connecting plumbing fixtures, for example, a pearl bath (how to do it yourself, it is written) to cold and hot water supply systems;
gas supply from the pipeline to gas appliances - stoves, water heaters, heating boilers;
installation connections during installation climatic equipment - air conditioners, chiller-fan coil systems, etc.;
connection of sprinklers of automatic fire extinguishing systems.

The scope of flexible pipelines assembled with fastening fittings (and eyeliners belong to this category) is even wider in the conditions of industrial enterprises and small businesses.

These connectors are expansion joints and are provided with tie rods to prevent over-stretching and over-stressing. Limited pressure capacity More expensive than rubber Diameters up to 12" Not as good at high temperatures like metal.

Ideal for aggressive chemical applications.
Often lasts longer than rubber or metal.
Good compression performance when thermal expansion is a concern.
Short face to face for a given movement.

This should lead you to right choice flexible connector on your pump.

Supply of air and gases, oil products, bulk substances, water and chemically aggressive liquids, drinks and food - in almost every such area, flexible pipes or their analogues are used.

On the market, a range of eyeliners for various purposes and for various conditions exploitation is rich enough.

Expansion joints, bellows and hoses for the energy sector

Disconnect connections for general piping applications in all types of power plants. Brushless steel bellows and compensators for high voltage switchgears and transformers. Used for critical valve seal applications. connections for gas turbines Belators for heat exchangers.

Various expansion joints for pipelines

Expansion joints for critical applications in nuclear power plants.
Special bellows for solar power applications.

Expansion joints are flexible piping elements used to move movements in piping systems.

When choosing, one of the decisive factors is the material of the product.

What materials is it made from

For the manufacture of flexible eyeliner use:

rubber hoses reinforced with stainless steel, aluminum or nylon braid (or no braid);
tubes made of flexible elastic polymers, for example, cross-linked polyethylene;
corrugated pipe stainless steel (bellows type connections).

Each of these products has its own advantages and disadvantages.

Rubber bellows for flexible connections

These movements can be caused by thermal expansion, ground movement, or misalignment. They are also successfully used in piping systems for water, gases and various chemical substances and are often found on large diesel and gas engines.

Flexible stainless steel hoses offer a wide range of solutions for a variety of applications such as correcting misalignment as thermal expansion, absorbing vibrations or facilitating repetitive movements. When using stainless steel braid, these hoses can withstand operating pressures up to 350 bar.

Rubber hose for water or gas with an aluminum braid serves up to 3 years and is designed for operation at a pressure not exceeding 5 atm., and a maximum operating temperature of not more than 80 degrees.

Its main disadvantage is the propensity of the protective braid material to corrosion, especially with prolonged exposure to moisture.

Rubber eyeliner with stainless steel reinforcement surpasses the previous version in terms of reliability and performance.

It's just a smarter decision.

It is simplified and simplifies the design.
It takes up less space.
He only needs one support.
It takes less time to install.
It moves in all directions.

Pipes transporting hot or chilled water, steam and chemicals are subject to varying internal temperatures as well as significant thermal expansion. While the Flex Hose and Braid Assembly is great for absorbing lateral movement and angular movement, it is not designed for axial compression or torque.

For such products, the allowable pressure reaches 10 atmospheres, Maximum temperature is 95 degrees.

Manufacturers claim a steel-braided liner to last at least 10 years. When installed, this perfect solution to connect the mixer.

In compression, the braid is loosened and its pressure is reduced, and the torque is complex stresses that quickly tire of the slag. If flexible hose and braid are to be used as a stress-compensating, motion-compensating component of the piping system, it must be installed in a configuration that minimizes axial compression.

Electronic pressure compensation in the dosing unit

Made from flexible bronze hose and braid, it supports lateral movement and angular movement. As long as the legs are designed to last long enough, the amount of displacement never exceeds the elastic limit of the hose, allowing it to flex indefinitely. It can even be designed with high speed lined hose, high pressure double braid and all stainless steel construction for material compatibility. There is no place for furs. Compared to traditional mechanical pressure compensation systems new system provides higher accuracy and reliability, as well as lower costs and easier installation.

The characteristics of such products, practically, ideally correspond to the requirements for the details of household communications, due to which they have received the maximum distribution.

Reinforced with polymer threads (nylon) rubber flexible eyeliner is one of the best offers on the market.

Due to the high resistance of the braid to various factors, they demonstrate impressive characteristics:

High weighing accuracy without bellows

Retrofit options are available for existing differential feeders.

In a closed dosing system, pressure fluctuations in the dosing funnel can seriously impair weighing accuracy. Be susceptible to damage or even ineffective. Depending on the situation and requirements, one sensor can be mounted on the dosing funnel and another on the distribution tube. For maximum efficiency software uses a compensation self-optimization algorithm. A separate field test package is available to evaluate potential problems due to pressure fluctuations in existing installations.

service life - up to 15 years;
permissible operating pressure- up to 20 atm.;
upper operating temperature limit- 110 degrees.

Some redundancy in performance is the main reason why these high quality products are not widely used.

Liners made of cross-linked polyethylene() in a metal braid combine flexibility, strength, reliability.

By means of a thermostatic valve, a simple system regulation of individual rooms. Overheating of rooms cannot be prevented by valves because they cannot "cool down". When using outdoor temperature or weather compensated flow temperature thermostatic radiator controllers should only accept fine room control. This makes the remaining control difference noticeable only in the event of interference. The system temperature must not act as a disturbing variable and the volume flow must be adapted to the space heating load.

For your information! Flexible hoses for cold and hot water mark by weaving into the coating of colored threads:

The use of flexible water pipes for gas supply and vice versa should also be avoided.

Rubber and polymer products have a common weak point - fittings for connections.

This is also called hydraulic balancing. The consequence of the missing regulation is that heating circuits with higher resistance do not heat up. The wrong "logical" conclusion would be to increase the pressure of the pump. This means, however, higher power consumption, possibly extreme flow noise, the installation of a bypass valve and air intake. This further increases the problems.

Bellows water connection

The liquid sensor in the thermostat head reacts to deviations from the room temperature setpoint. As room temperature increases, the liquid expands in the liquid sensing element and compresses the bellows. As a result, the valve closes continuously, and thermal power heating element is reduced by a small amount of flow. With the valve closed, the load-relieving device with its spring ensures that the forces resulting from the further expansion of the bellows are compensated and not transferred to the valve lifter.

They have special requirements:

reliable crimping;
material resistance to corrosion;
tightness of interfaces.

Fittings made of brass or stainless steel with sealing gaskets mounted on a flexible hose make it possible to fulfill all the conditions.

But the use of these materials increases the cost of the product..

When the room temperature drops, the bellows expands again and the valve opens via an internal spring in the valve insert. This results in stepless actuation of the radiator valve with fine adjustment of the volumetric flow of the coolant to the radiator. In the case of correct hydraulic adjustment and an appropriate heating curve, the purpose of this device is fulfilled. It basically closes at ambient temperature.

Before installing the control valve in the pipeline, the system must be properly flushed and, if necessary, cleaned. To obtain satisfactory control of the control valve, it must have a sufficiently large internal resistance to pressure loss in the system. When designing control or thermostatic valves for a pipe network, the following terms must be known.

Some manufacturers, taking care of product quality, take such a step, even taking on warranty obligations (warranty period is 1-2 years).

But at the same time, they put forward additional requirements - the installation of products only by certified specialists and compliance with additional operating conditions, for example, the absence of water hammer in the system.

The thermostatically controlled radiator valve is a proportional controller in which the setpoint on the thermostatic head is assigned the corresponding stroke. If the room temperature changes, the valve lift changes proportionally. The sensor compares the actual room temperature with the setpoint setpoint and sets the volume flow to the radiator via the valve stem. Thus, if the room temperature drops, the valve opens or closes as the room temperature rises.

Bellows flexible stainless steel hoses surpass all listed types characteristics and free from most of the shortcomings.

Design, characteristics, advantages

The bellows hose is a corrugated hose made of stainless steel, such as AISI 304.

This makes it possible to maintain a constant room temperature within the proportional band. The proportional band is the change in temperature required to open the valve to such an extent that the volumetric flow is achieved. Valve control Valve power determines the ratio α of pressure loss in the valve to the total pressure loss in the system.

The maximum differential pressure is specified by the valve manufacturers and must not be exceeded to ensure closure and precise control. In addition, an excessively high pressure difference causes mechanical energy to be converted into sound energy by throttling at the narrowest point of the valve, resulting in annoying noise and erosion.

The production of the tube is carried out according to various technologies- it can be welded or seamless, but this does not have a decisive effect on the main characteristics of the product.

The wall thickness is determined by the required performance and for most applications does not exceed 0.3 mm.

As a rule, such eyeliners are equipped with union nuts. made of the same grade of steel or nickel-plated (rarely chrome-plated) brass or bronze.

Too high a pressure difference is also created when many of the thermostatic valves in a building close. When circulation pump with a constant flow or delivery head, the flow increases on stationary open valves, which can lead not only to noise, but also to the closing of additional valves.

Bellows gas connection idrosapiens udi-gas

With this pumping technology, the pump characteristic changes as the speed is adjusted. Bypass valves should be in the past, or at least used properly. Because of different options radiator installations, there are different thermostat heads. In any case, it is important that the sensor element can detect the "real" room temperature. Only at the right room temperature is “correct heating” possible. The thermostat head used depends on the following factors.

For reliable fixation of nuts and obtaining a high-quality connection with pipelines, the ends of the hose (2-3 corrugations) are folded.

Attention! Bellows connections are not used without a retaining ring, which ensures uniform fit of the seam and sealing gasket to the pipe or fitting during installation.

To connect a stainless steel piping with equipment for a fitting or with pipes of a larger (smaller) diameter, use the appropriate adapters made of stainless steel or brass.

Remote sensors are installed whenever the measuring point cannot correctly detect the room temperature. For example, with cold air under the windows, strong heat radiation from the radiator or hidden thermostat heads through the curtains, they measure the wrong and uneven temperature. But even with longer radiators, the sensor is placed under the radiator on the base, where it detects the air in the room.

Remote control is used for radiators and convectors. The thermostatic heads on these valves have a hidden setpoint that can only be changed with a special tool. They also have a built-in anti-theft device and increased bending strength. This makes them vandal resistant.

Operating parameters

The materials used in the manufacture of stainless steel liners determine their unique characteristics:

service life of products exceeds 20 years, in practice, such eyeliners can last longer, especially polymer ones;
medium temperature range- from -40 to +200 degrees;
operating pressure depends on the diameter of the hose and the thickness of its walls, and for products with a diameter of 0.5 "exceeds 15 atmospheres, and the burst pressure is 30 atmospheres.

It should be noted that the most unreliable element of such an eyeliner is the gasket.

To obtain the appropriate characteristics during installation, gaskets made of paronite, fluoroplastic or copper are used (which better fum tape or thread Tangit, it is written in the article).

Attention! The seal experiences the same loads as the entire product, so the use of gaskets with a thickness of at least 2.5 mm is recommended.

The properties of the main material of the product - stainless steel determine other advantages of bellows flexible hoses:

In addition, the corrugated hose does not change the effective section when bent, which ensures uniform pressure in all areas.

An additional advantage of bellows liners is the possibility of using them as expansion joints (installation on polypropylene pipes described) for polymer pipelines.

For industrial applications these products are almost perfect.

They can be used for the transportation of aggressive media and oil products, where other materials cannot be used (read the rules for testing pipelines for strength and tightness on the page).

High wear resistance allows them to be used for bulk solids of various fractional composition.

Corrosion resistance expands the scope for conditions with high humidity, high salt content, etc., for example, for use in shipbuilding.

Special mention deserves the flexibility of stainless steel bellows connections.

In this parameter, the products are significantly inferior to rubber counterparts.

Because of this corrugated eyeliners not always convenient to use, especially in a limited installation space.

However, this has an additional advantage.- products keep the given shape and can be used as sections of pipelines without additional structures.

The properties of steel eyeliners also determine some installation requirements.

Installation rules for sanitary accessories

The main points when working with flexible eyeliners are:

it is not allowed to bend the radius of the eyeliners less than that specified in the documentation;
required product configuration attached before connecting to appliances and pipes;
an inflection closer than the established distance to the ends of the product (the places where the union nuts are installed) is unacceptable;
when installing the eyeliner, twisting should be avoided;
excessive stretching of the product, as well as repeated bending, can lead to a violation of the integrity of the walls;
damaged bellows liners cannot be repaired and are replaced entirely.

On a note

Practical note! should be adhered to and general requirements for the installation of such connections.

What to look for when buying a flexible water supply, how to properly mount it on pipelines - you will find out the answers by watching the video.

Flexible bellows-type WATER connections are flexible metal pipes, with the help of which water is supplied from the pipe to the device. This product recommended for use in accordance with GOST R 52209-2004. The eyeliner is made of AISI316L stainless steel.

The bellows inlet for water differs from the bellows inlet for gas in that the fittings that are attached to the hose using argon-arc welding are also made of AISI316L stainless steel.

The eyeliner has a maximum service life of 25 years. The range of applications is very diverse, and is used wherever installation with a conventional flexible hose is difficult or a much more reliable connection is needed.

The bellows connection is very convenient, because you do not have to precisely adjust the location of the device to the location of the water supply, as you have to do when using pipes.

The bellows connection is made of stainless steel. and withstands a working pressure of 16 bar. Another important advantage, which the bellows eyeliner has - temperature stability: the eyeliner is able to withstand frost at - 40 and heat + 120 degrees Celsius. The bellows supply is devoid of a significant number of disadvantages inherent in rubber liner. With proper operation, the service life of the bellows connection can reach up to 25 years.