Flexible bellows connection for water 1 2. Flexible bellows connection for water - corrugated, made of stainless steel. Flexible connection for mixer: Design features.

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

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

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

What is it and where is it used

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

Tightening rods prevent twisting of the joint and eliminate axial loads until the joint is compressed. Pins are added to these connectors at the factory. Thermal expansion induced compression handles Excellent for high temperature applications Can be designed for higher pressure applications Ideal for applications with many chemicals except 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 folding options and are limited to more high pressures.

Such products are in demand for:

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

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

These connectors are expansion joints and have tie rods to prevent overstretching and excessive stress. Limited pressure capacity More expensive than rubber Diameters up to 12 inches Not as good at high temperatures like metal.

Ideal for aggressive chemical applications.
Often lasts longer than rubber or metal.
Good compression characteristics when thermal expansion is a problem.
Short face to face for this move.

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

Supply of air and gases, petroleum products, bulk solids, water and chemically aggressive liquids, drinks and food - in practically each of these areas flexible lines or their analogues are used.

On the market, an assortment of eyeliners for various purposes and for various conditions operation is quite rich.

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 distribution devices 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 use in solar power plants.

Expansion joints are flexible piping elements used to accommodate 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 braided stainless steel, aluminum or nylon (or without braid);
tubes made of flexible elastic polymers, for example, cross-linked polyethylene;
corrugated pipe made of stainless steel (bellows type liners).

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 eliminating misalignment such as thermal expansion, absorbing vibration or easing repetitive motion. When using stainless steel braiding, these hoses can withstand operating pressures of up to 350 bar.

Rubber water hose or gas with an aluminum braid lasts 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 tendency of the protective braiding material to corrosion, especially with prolonged exposure to moisture.

The rubber liner with stainless steel reinforcement is superior to the previous version in terms of reliability and performance characteristics.

It's just a smarter solution.

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

Pipes carrying hot or chilled water, steam and chemicals are subject to varying internal temperatures as well as significant thermal expansion. Although the flexible hose and braid assembly is excellent for absorbing lateral movement and angular movement, it is not designed to withstand axial compression or torque.

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

Manufacturers claim a service life of steel braided eyeliners of at least 10 years. When installing this perfect solution for connecting the mixer.

When compressed, the streamer is weakened and its pressure is reduced, and the torque represents complex stresses that quickly tire the slag. If flexible hose and braid are to be used as a stress-relieving, motion-compensating component of a 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 with sufficient life, the amount of displacement never exceeds the elastic limit of the hose, allowing it to flex indefinitely. It can even be designed with lined hose for high speeds, double braided for high pressures, and all stainless steel construction for material compatibility. There's no room for furs. Compared to traditional mechanical pressure compensation systems new system provides higher accuracy and reliability, while also reducing costs and simplifying installation.

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

Reinforced with polymer threads (nylon) rubber flexible liner 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 hopper can seriously impair weighing accuracy. Be susceptible to damage or even ineffective. Depending on the situation and requirements, one sensor can be installed on the dosing funnel and another on the dispensing 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 characteristics is the main reason why these high-quality products are not widely used.

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

Using a thermostatic valve must be created 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 when interference occurs. The system temperature should not act as a disturbance variable and the volume flow should be adapted to the space heating load.

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

It is also necessary to avoid using flexible water connections to supply gas and vice versa.

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

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

Bellows liner for water

The liquid sensor in the thermostat head reacts to deviations from the set room temperature. 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 flow volume. With the valve closed, the load relief device with its spring ensures that the forces resulting from further expansion of the bellows are compensated and are not transmitted to the valve tappet.

They have special requirements:

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

Fittings made of brass or stainless steel with sealing gaskets mounted on a flexible line allow all conditions to be met.

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 precise regulation of the volume flow of coolant to the radiator. If the hydraulic adjustment is correct and the heating curve is correct, the purpose of this device is fulfilled. It basically closes at ambient temperature.

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

Some manufacturers, caring about the quality of their products, take this step, even accepting warranty obligations (warranty period 1-2 years).

But at the same time, they put forward additional requirements - 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 set value on the thermostatic head is assigned a corresponding stroke. If the room temperature changes, a proportional change in valve lift occurs. The sensor compares the existing room temperature with the setpoint value and sets the volume flow to the radiator through the valve stem. Thus, if the room temperature drops, the valve opens or closes as the room temperature rises.

Flexible bellows hoses made of stainless steel surpasses everything listed types according to the characteristics and are free from most of the shortcomings.

Design, characteristics, advantages

The bellows flexible connection is a corrugated hose made of stainless steel, for example AISI 304.

This allows you to maintain a constant room temperature within the proportional range. Proportional band is the temperature change required to open the valve to such an extent that 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 pressure drop is determined by the valve manufacturers and should not be exceeded to ensure closure and accurate control. In addition, excessively high pressure differences cause mechanical energy to be converted into sound energy by throttling at the narrowest point of the valve, resulting in annoying noise and erosion.

The tube is manufactured according to various technologies– it can be welded or seamless, but this does not have a decisive influence on the main characteristics of the product.

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

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

Too high a pressure difference is also created when many of the thermostatic valves in a building are closed. When circulation pump With a constant flow rate or feed 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 a thing of the past, or at least used properly. Because of different options When installing radiators, there are different thermostat heads. In any case, it is important that the sensor element can detect the “real” room temperature. Only at the correct room temperature is “correct heating” possible. The thermostat head used depends on the following factors.

To securely fix the nuts and obtain a high-quality connection with pipelines, the ends of the hose (2-3 corrugations) are folded.

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

To connect the stainless steel liner with fitting equipment or with pipes of larger (smaller) diameter, appropriate adapters made of stainless steel or brass are used.

Remote sensors are installed whenever the measuring point cannot correctly determine the room temperature. For example, when there is cold air under the windows, strong heat radiation from the radiator or through the curtains, hidden thermostat heads measure an incorrect and uneven temperature. But even with longer radiators, the sensor is placed under the radiator at 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 set point that can only be changed using 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 eyeliners determine their unique characteristics:

Product service life exceeds 20 years, in practice, such eyeliners can last longer, especially polymer ones;
temperature range of the transported medium– 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 a liner is the sealing gasket.

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

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

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

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

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

For industrial applications Such products are practically ideal.

They can be used for transporting aggressive media and petroleum 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 compositions.

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

The flexibility of the stainless steel bellows hoses deserves special mention.

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

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

However, there is an additional benefit to this– the products hold their given shape and can be used as pipeline sections without additional structures.

The properties of steel connections also determine some installation requirements.

Installation rules for plumbing accessories

The main points when working with flexible eyeliners are:

The bend radius of the hoses is not allowed to be less than that specified in the documentation;
required product configuration attached before connecting to devices and pipes;
bending closer than the established distance to the ends of the product (places for installing union nuts) is unacceptable;
When installing the liner, 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 connections cannot be repaired and must be replaced entirely.

On a note

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

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

Flexible bellows-type hose for WATER 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 liner is made of AISI316L stainless steel.

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

The liner has a maximum service life of 25 years. The range of applications is very diverse, and can be used wherever installation using conventional flexible hoses is difficult or a much more reliable connection is required

The bellows connection is very convenient, since 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 liner is made of stainless steel and can withstand a working pressure of 16 Bar. Another important advantage, which the bellows eyeliner has, is temperature resistance: the eyeliner can withstand frost of - 40 and heat of + 120 degrees Celsius. The bellows liner does not have a significant number of disadvantages inherent in the rubber liner. With proper use, the service life of the bellows liner can reach up to 25 years.