Steam pressure regulators behind. Pressure regulator valves

The service life and compliance with the rules of its operation depend not only on its correct installation, but also on the quality of the water pressure in the pipes. Sudden surges, pressure drops and water hammer often cause damage to expensive equipment. For the same reason, leaks occur, leading to significant financial costs. You can save yourself from such troubles if you install a pressure regulator on the water supply system after you.

Water pressure valve: installation method

The main purpose of the water pressure valve is to ensure stable water pressure inside utilities, regardless of their type. Depending on the installation location, a pressure regulator is distinguished “after itself” and “before itself”. The first regulates the water pressure as it exits through the device, and the second at the inlet.

Water valve: design features

Water control valves can be: flow, diaphragm, piston, automatic and electronic. Flow valves have the simplest design. Piston ones are not as reliable due to the likelihood of corrosion associated with impurities contained in the water.
When using a membrane regulator, you can be sure of its durable and correct operation. The device of such a regulator is based on the presence of two chambers and a diaphragm between them. Cleaning such a regulator is much less common than other varieties.

What issues do water control valves solve?

are used to solve the following issues when organizing a water supply system:

By stabilizing the pressure inside the water main, compliance with the requirements for optimal permissible parameters is ensured.
The probability of water hammer in the system, leading to leaks and equipment failure, is reduced to zero.
Due to the stabilization of the water pressure, the devices, the correct operation of which is directly related to the indicators of the liquid pressure at the inlet, operate in the normal mode.
By installing a water pressure control valve, its economical consumption is ensured.
When a leak occurs, the valve closes automatically and water does not enter the room so quickly.
Disappears uncomfortable noise that accompanies the opening of the tap at high pressure and high water pressure.

How does the membrane pressure regulator "after itself" work

Consists of the following elements:

valve inlet and outlet.
A branch pipe leading to a chamber with a membrane.
Membrane chambers.
Springs.
Locking disk.

The principle of operation of such a regulator is that when the water pressure increases and the chamber with the membrane is filled, a rod is activated, which is connected to the locking disk. The membrane presses on it, and the disk blocks the flow of water (in whole or in part).
When the pressure inside the chamber stabilizes, the locking disc opens the hole. The regulator also works when the pressure in the system decreases. In this case, the liquid returns to the valve through the nozzle from the membrane chamber. By reducing the pressure in the chamber, the locking disk opens and the water pressure increases with an increase in its pressure to the optimum value.
The main advantage of such a device lies in its reliability and ease of operation.

Features and benefits of bermad valves

The controller has the following features:

During the manufacture of the device, the current international standards are taken into account.
The device is manufactured on the basis of a unique patented technology.
For the manufacture of the device, modern, technological materials from metal and composites are used.
The device is universal and operates in the same mode, regardless of the quality and composition of the passed fluid.
The company has developed specialized and multi-purpose devices that are used depending on the purpose and operating conditions.

Main applications: steam, CO2, water, compressed air - on most non-flammable and non-aggressive liquid and gaseous media.

Why do we need pressure regulators - bypass valves and pressure reducing valves to regulate the pressure after ourselves?
At the enterprise, there are a lot of consumers of heat energy, some need a pressure of 2 bar, others 4, and a third 8, but you always have to produce steam with maximum parameters, and only then reduce the pressure to the required value. Pressure regulators are not only pressure reducing valves, but also bypass valves, however, bypass valves are not so often used in steam and condensate systems.

The pressure reducing valve is

pressure regulator After myself, the main purpose is to reduce the pressure after itself and maintain it at a certain level (in the area after itself), regardless of pressure surges to the regulator (at its inlet). Pressure surges are caused by changes in steam consumption, the pressure regulator maintains a constant pressure level.

The bypass valve is pressure regulator TO itself, is used much less frequently than a pressure reducing valve, it is practically not used for steam. Bypass valves are most commonly used to bypass pumps. When the pump delivers too much pressure, the bypass valve leads this excess pressure back to the suction (bypass pressure), such a system saves the pump.

3 main types of pressure reducing valves for steam

from simpler to more complex

bellows type(e.g. ADCA PRV25)

It has a flexible metal bellows inside with a relatively small area, as a result of which the bellows pressure reducing valve is considered the least sensitive, suitable for coarser pressure adjustment after itself. If the flow rate of steam passing through the valve does not change significantly during operation, a bellows-type pressure reducing valve will do just fine. Due to low accuracy and sensitivity, this valve is produced only in small sizes DN 15-20-25. One of the disadvantages of this valve is the relatively small throughput. The main advantage is the simple design.

Pressure regulator downstream membrane(e.g. ADCA RP45)

There is a rubber membrane inside the metal plate, the membrane area is much higher than on the bellows pressure reducing valve, hence the higher sensitivity and relatively greater accuracy of maintaining pressure after itself. A very common type of pressure reducing valves, capable of operating in systems with high dynamics of steam flow changes, in comparison with a bellows valve, a diaphragm valve has a higher throughput - this is also a significant plus. An extremely durable type of pressure reducing valve, if the filter in front of the pressure reducing valve is correctly installed - even the rubber membrane in it can work for more than 10 years.

Pressure regulator downstream pilot(e.g. ADCA PRV47)

The main trump card of the pilot pressure regulator after itself is the highest sensitivity and adjustment accuracy.

The most advanced design, the most accurate pressure regulator, but at the same time the most “gentle”. This valve is equipped with a piston drive, there are many small grooves in the design, as a result, the valve is very sensitive to steam quality. In no case should such a pressure reducing valve be placed in a system with a high level of mechanical impurities in the steam, it is recommended to use it with stainless steel pipelines or install a fine steam filter (fabric), this is the only way to ensure the long operation of such a valve

Selection of pressure regulator

Always install a pressure regulator downstream of a smaller size than the main pipeline! A common misconception is fitting a size-to-size pressure reducing valve.

A pressure reducing valve that matches the pipe size always turns out to be more powerful than the technological process requires, because of this the valve does not work accurately, imagine a valve operating at 10-30% of its normal capacity, in fact it is not much different from the open-closed regulation ”and the main functionality of such a valve remains unused.
The main parameters for selecting a pressure regulator after yourself:

Environment type.
Inlet pressure.
outlet pressure.
Medium consumption (min. max).
Medium temperature.
Connection type.

THE VALVE DIAMETER WILL BE DETERMINED BASED ON STEAM, PRESSURE, FLOW AND MEDIUM AND NOT FROM THE PIPE DIAMETER.

Selection by pipe - absolutely not. When selecting a pressure reducing valve, it is always necessary to narrow the pipe in front of the valve and widen the pipeline BEHIND the valve.

What does the ideal steam system reducer look like?

The normal selection of the reduction node is carried out based on the parameters of the system.

In a nutshell, we describe the principle of selecting a pressure reducing valve assembly.

Suppose the main pipeline before the pressure reducing valve is f 40, in this case the pressure reducing valve itself will turn out to be slightly smaller, approximately DN 32.
BEHIND the valve, it is usually necessary to expand the pipeline, usually drastically.
That is, BEFORE the pressure reducing valve, the diameter of the steam pipe was f 40, and BEHIND the pressure reducing valve, the pipe will need to be expanded to f 50 or even f 65. (rough)
Why is it necessary to expand the pipeline BEHIND the pressure reducing valve?
We lowered the pressure - the steam expanded - it is necessary to expand the pipeline to ensure the normal passage of steam through the system.
Tell us the parameters of your steam system and we will make a full calculation of the required pressure with optimal performance.

List of equipment for correct operation reduction node:

Condensate drain before pressure reducing valve - Mandatory
Shut-off valve in front of the pressure reducing valve - Mandatory
Filter before pressure reducing valve - Mandatory
Relief valve - Mandatory
The steam separator is perfect.

In pipeline systems, when transporting various substances, the pressure must be maintained at a set level.

This is very important for heat supply systems, ventilation, fuel supply, for the operation of pumping station equipment, heating points, etc.

To maintain pressure in automatic mode, direct-acting regulators are installed, which operate at the expense of the energy of a moving stream, and indirect-acting, requiring external energy sources.

Such devices maintain flow pressure in the direction of travel until it is installed. The water pressure is maintained at the required level by changing the size of the flow area.

Device, principle of operation and classification

Manufacturers produce a wide range of products that differ in design, materials from which they are made, manufacturing technology, dimensions and weight, principle of operation, but any of them must contain the following elements:

case (cast iron, steel, brass, copper);

control part (piston, bellows, diaphragm);
setter (spring, lever-load, pneumatic);
impulse line.

The principle of operation is based on the use of water pressure to move the valve plug, while the degree of opening of the passage section is proportional to the deviation of the controlled pressure from the required value.

The second name of this type of control valves: proportional regulators. The pressure regulator to itself automatically maintains the working pressure of the transported medium and, if it exceeds the required value, it opens the section until it equals the set value.

The most commonly used spring and diaphragm pressure regulators. For spring pressure regulators, the measuring element is the valve plug, and for membrane pressure regulators, the membrane.

Both types have a spring adjuster. Such equipment is characterized by high accuracy of maintaining the pressure value, simplicity of design and maintainability.

The classification is based on constructive differences:

principle of action (direct and indirect);

loading method (spring, lever-load or pneumatic);

design of the working body (single and double seats);

type of sensitive element (piston, bellows, membrane);

plunger type (piston, poppet, hollow, rod, multistage);

method of connection to the pipeline (flanged, coupling, by welding);

conditional pass in mm;

throughput in m 3 / hour.

The pressure regulator with indirect action has in its design a pressure sensor that performs the functions of a measuring element, a programmable controller and a control valve with an electric drive. The latter performs the function of the actuator.

Key benefits of pressure regulators

Product benefits include:

a wide range of manufactured devices, which allows you to choose it for any need;

the ability to stabilize the pressure of the transported medium;

the ability to maintain pressure in various ranges;

adjustment accuracy;

easy assembly and dismantling;

the ability to significantly reduce the noise level in pipelines;

maintainability;

high degree of reliability;

long service life.

For products of indirect action, this also includes the fact that the work can be controlled remotely.

Dependence on the need to have an external control source for this type of valve does not always make it possible to use this equipment.

Specifications

When choosing a pressure regulator to yourself, special attention is paid to such factors:

conditional passage, indicated in mm;

nominal working pressure in bar, MPa or kgf / cm 2;

throughput in m 3 / hour;

setting range;

operating temperature range in which it can operate;

method of connection to the pipeline.

If you need a pressure regulator to yourself and control valves for heating and heat supply, contact the professionals

by free phone: 8-800-77-55-449

or by email on the site

www.gardarikamarket.ru

Calculation of the pressure regulator "after itself" consists in determining the throughput of the regulator, the required setting range, checking for noise and cavitation.

Bandwidth calculation

The dependence of head loss on flow through the pressure regulator is called capacity - Kvs.

Kvs - capacity, numerically equal to the flow rate in m³/h, through a fully open valve of the pressure regulator, at which the pressure loss on it is equal to 1 bar.

Kv - the same, with a partial opening of the regulator shutter.

Knowing that when the flow rate changes by “n” times, the head loss on the regulator changes by “n” squared times, it is not difficult to determine the required Kv of the pressure regulator by substituting the calculated flow rate and excess pressure into the equation.

Some manufacturers recommend selecting a pressure regulator with the nearest higher Kvs value to the calculated Kv value. This selection approach allows more accurate control of flow rates below the specified value, but does not allow increasing the flow rate above the specified value, which quite often has to be exceeded. We do not criticize the above method, but we recommend selecting pressure regulators "downstream" in such a way that the required flow rate is in the range from 50 to 70% of the stroke. The pressure regulator, calculated in this way, will be able, with sufficient accuracy, both to reduce the flow rate relative to the specified one, and to slightly increase it.

The above calculation algorithm lists downstream pressure regulators for which the required Kv value falls within the stroke range of 40 to 70%.

The results of the selection show the percentage of opening of the pressure regulator gate, at which a given excess pressure is throttled at a given flow rate.

Setting range selection

The setting range of the pressure regulator depends on the compression force of the spring. Some pressure regulators are equipped as standard with one spring and have only one pressure setting range, and some can be equipped with springs of different stiffness and have several setting ranges. The pressure that the pressure regulator will maintain "downstream" should be approximately in the middle third of the control range.

The above algorithm for selecting a pressure regulator displays a list of regulators for which the specified pressure falls within the range from 20 to 80% of the range of supported pressures.

When choosing the setting range, it must be taken into account that the permissible error in the spring calibration at the limit values of the setting range is 10%.

Calculation of the regulator for the occurrence of cavitation

Cavitation is the formation of steam bubbles in a water stream, which manifests itself when the pressure in it decreases below the saturation pressure of water vapor. The Bernoulli equation describes the effect of increasing the flow velocity and reducing the pressure in it, which occurs when the flow section narrows. The flow area between the valve and the seat of the pressure regulator is the very narrowing, the pressure in which can drop to saturation pressure, and the place where cavitation is most likely to form. Vapor bubbles are unstable, they appear sharply and also collapse sharply, this leads to metal particles being eaten out of the regulator shutter, which will inevitably cause premature wear. In addition to wear, cavitation leads to increased noise during operation of the regulator.

The main factors affecting the occurrence of cavitation:

Water temperature - the higher it is, the greater the likelihood of cavitation.

Water pressure - in front of the pressure regulator, the higher it is, the less likely it is to cause cavitation.

Throttled pressure - the higher it is, the higher the likelihood of cavitation.

The cavitation characteristic of the regulator is determined by the characteristics of the throttling element of the regulator. The cavitation coefficient is different for different types of pressure regulators and should be indicated in their technical characteristics, but since most manufacturers do not indicate this value, the calculation algorithm includes a range of the most probable cavitation coefficients.

As a result of the cavitation test, the following result can be produced:

"No" - there will definitely be no cavitation.
"Possible" - cavitation may occur on valves of some designs, it is recommended to change one of the above-described influence factors.
"Yes" - cavitation will definitely be, change one of the factors influencing the occurrence of cavitation.

Calculation of the regulator for the occurrence of noise

High flow rates at the pressure regulator inlet can cause high noise levels. For most rooms where pressure regulators are installed, the permissible noise level is 35-40 dB(A) which corresponds to a velocity in the valve inlet of approximately 3m/s. Therefore, when selecting a pressure regulator, it is recommended not to exceed the indicated speed.

The RAF60 valve is a pilot-acting, diaphragm-type pressure reducing valve that regulates downstream pressure. The pressure regulator RAF60 (port) / RAF60A (angle) is controlled by a pilot valve that controls the outlet pressure and regulates the opening and closing of the membrane, thereby maintaining the set pressure downstream of the regulator. The pressure regulator RAF-60 is designed for a maximum pressure of 16bar. In case a pressure exceeding 16bar is required, the valve model G-60 must be ordered (see relevant section)

When the pressure in the pilot line increases 1 When the outlet pressure is lower than required, the regulator automatically opens, otherwise the regulator automatically closes. When excess pressure enters the control chamber above the diaphragm, the regulator closes. Otherwise, the regulator will open due to the pressure acting under the diaphragm.

The pressure regulator RAF60 maintains the set pressure if there is a liquid flow through the valve. In the case of dead-end operation, the valve will set the set pressure plus one bar.

Regulators are supplied with pilot valves with various pressure control ranges:

0.54 - 4 bar; 0.5 - 6 bar; 2 -10 bar; 2- 16 bar - standard version (stock in stock).

Materials: Body and cover - ductile iron with Rilsan (Nilon11), epoxy

or enamel - special order.

Bolts and nuts: galvanized steel.

Diaphragm: natural rubber.

Before valve installation flush the pipeline to clean it of deposits, dirt and other things that may affect the operation of the valve.

Install according to the arrow on the valve cover indicating the direction of flow.

Check for leaks, re-tighten bolts and fittings if necessary.

1. Frame

2. Lid

3. Membrane

4. Binding filter

5. Stopcock

6. Stopcock

7. Control valve

8. Stopcock

9. Managing Pilot

10. Adjusting screw

Adjustment procedure:

1. Make sure there is inlet pressure.

2. Close stopcocks №6 and №8 . Open the stopcock №5 and supply water to the valve.

3. Close the regulating valve № 7 to the end and then open it again 1-2 turns. Regulating valve № 7 adjusts the response rate of the valve. The more open the control valve № 7 the faster this reaction. When adjusting the control valve, please remember that too fast a response can lead to water hammer.

4. Loosen the lock nut and turn the adjusting screw №10 counterclockwise so that there is almost no pressure in the pilot spring.

5. Open the stopcock № 6.

6. Turn the adjusting screw № 10 clockwise until the valve begins to open.

7. To increase the inlet pressure, continue to turn the adjusting screw № 10 clockwise (1) turn at a time, taking small breaks between turns to allow the valve to adapt. Check the inlet pressure until the desired pressure is reached. Tighten the lock nut of the adjusting screw № 10.

8. To decrease the inlet pressure, turn the adjusting screw № 10 counterclockwise (1) turn at a time, taking a short break between turns to allow the valve to adapt. Check the inlet pressure until the desired pressure is reached.

To fully open the valve, close the stopcocks № 5 and № 6 and open the stopcock № 8 . Please keep in mind that if in this case the inlet pressure will be the same as the outlet.

To close the valve, close the stopcocks № 6 and № 8 , and open the stopcock № 5 .

To maintain the set pressure, open shut-off valves No. 5 and No. 6 and close the stopcock № 8.

Price equipment is listed in price list, which can be obtained by sending a request to our e-mail or by contacting the managers of our company.

Attention!

When ordering model RAF-60 pressure regulators, be sure to specify the inlet pressure and the adjustment range in which it is necessary to maintain the specified pressure after the valve.