Installation and installation of differential pressure regulators. Pressure regulator after itself, before itself and differential pressure Automatic differential pressure regulator operating principle

The regulator is designed to maintain a constant (preset) pressure drop in a process unit connected in series with the regulator valve.

In the absence of a signal (energy), the regulator valve is normally open.

The regulator consists of three main elements: valve (01), servomotor (02) (diaphragm unit) and adjuster (03).

The regulator valve (01) is single-seated, with a balanced plate.

At the point where the pulse is taken, the regulator must be equipped with a ZWD valve. The ZWD valve is supplied separately.

Flange connection.

* - other materials depending on working environment

** -others on request

Equipment flanges are made according to EN 1092-1(2)

The operation of household plumbing requires a responsible approach. Reliable operation will only ensure compliance with all manufacturer's recommendations.

In most cases, the passport specifies the optimal and maximum pressure values ​​in the water pipeline. To ensure the required operating mode, it is necessary to install a water pressure regulator in the line.

Otherwise, pressure drops and water hammer will lead to equipment breakdown and leaks.

Regulators are used in various networks from household to industrial. They are built into wiring for irrigation, fire extinguishing, and in water filling station systems.

The place for their location is determined at the entrance to the riser or into the building, after pumping equipment and shut-off valve units.

Any type of pressure regulator is sensitive to the presence of dirt and mechanical impurities in the water. In order to increase the resource of trouble-free operation, it is recommended to install a filter at the inlet for water purification.

Description of the regulator

A water pressure regulator is installed in the water supply system in order to stabilize the incoming water flow and prevent a critical pressure level.

The operation of the regulator is based on the principle of compensation by a spring or membrane of the maximum pressure of the incoming flow. This occurs due to equalization of efforts. The forces of the spring and diaphragm come into opposition.

When water is drawn in, the pressure at the outlet drops. Accordingly, the pressure on the diaphragm decreases. As a result, the valve opens.

The increase in pressure continues until the force of the diaphragm and the elastic force of the spring are balanced.

The valve inlet pressure does not affect the opening and closing of the spring valve. The outlet pressure remains unchanged despite changes in inlet pressure.

Thus, it is possible to maintain constant pressure at the outlet, which protects internal communications from water hammer and overloads. Pressure drops in networks powered by a pump are especially relevant.

The metal body of the device has two threaded outlets for connection to the water supply system. Some models have a pressure gauge that displays the pressure in the system. Such designs also provide an adjustment screw to adjust the maximum pressure.

Advantages of using pressure regulators:

• Always stable water pressure at the outlet, regardless of the main pressure
• No noise produced by high water pressure
• Reduced consumption
• protects the internal network from water hammer
• Reliable and safe work equipment connected to the water supply network

Principle of operation

The operating principle of the pressure regulator can be:

• Dynamic

Provides constant regulation of water flow. Installed in industry and on major highways.

• Static

Designed for networks of uneven water consumption. Used in apartments and private houses.

Devices are classified according to their location:

• "Before the regulator"

They are closed when there is no pressure and open if it increases at the inlet to the device, thereby limiting the limit value.

• "After the regulator"

They are open when there is no pressure. If the maximum water pressure is exceeded, the outlets are closed.

Static type devices operate on the “after the regulator” principle, that is, they ensure constant outlet pressure

Types of regulator designs

There are three design types of regulators:

1. Piston

They are distinguished by their simplicity of design and low price, therefore they are the most common. A spring-loaded piston located inside closes the passage hole of the pipeline. This ensures constant outlet pressure. The control range is within 1-5 atm.

The piston does not wear out, which significantly increases the service life of such a device.

Design flaw of this type is a moving piston that requires only filtered water at the inlet. The second disadvantage is the rapid wear of moving parts that limit the maximum flow of water.

Corrosion may occur on internal surfaces.

1. Membrane

Flow regulation occurs due to the action of a spring-loaded membrane located in a separate, isolated chamber. The membrane opens and closes the control valve.

The internal cavity is divided by a membrane into two zones. One is in contact with water, and the other is well insulated. Thereby dirty water does not pass through the membrane layer.

The design is reliable and unpretentious. The diaphragm regulator has rust protection inside. At correct operation no maintenance required.

Characterized by a wide pressure control zone and proportionality. It is possible to control the flow rate from 0.5 to 3 m 3 /hour.

The disadvantage is the appearance of cracks, ruptures and delamination on the membrane after a certain period of operation. Therefore, regular monitoring of the membrane condition is necessary.

Has a higher cost.

1. Flow-through

The labyrinth in the middle of the body allows for dynamic pressure adjustment. The flow rate decreases as separations pass through and large number turns.

The regulator is installed in networks for irrigation and watering. There are no moving mechanisms in it, so parts made of plastic materials are used.

Before regulators of this type it is required additional installation valve or regulator in the inlet section. The operating control range of the device is 0.5-3 atm.

The flow regulator has a low cost.

1. Electronic

An electronic device ensures that the pump is turned on low power at the time of drawing water from the network.

The design includes a housing, a diaphragm, boards, and connectors for connection. The regulator is equipped with a sensor to protect against water hammer and start pumping equipment “dry”.

The device operates silently.

The electronic device should be installed up to the first fence line. Underwater connections provide convenient integration into the pipeline. Before starting, the pump tank is filled with water.

The factory setting of the electronic regulator is 1.5 bar. Adjust the starting pressure value using a special screwdriver, taking into account that the nominal value should exceed the starting pressure by 0.8 bar.

Operating parameters of regulators:

• Maximum maximum pressure to ensure long-term operation. The parameter is regulated by GOST 26349-84.
• The value of the nominal diameter in accordance with the nominal diameter = m of the water supply system (GOST 28338-89).
• The throughput of the device, when the established control limits are maintained, in m 3 / hour.
• Operating range of regulation.
• Temperature range of operation of the device, affecting the ability to operate in heating and supply lines hot water, and also when low temperatures air.

Existing varieties

The pressure regulator is used in various fields farms and industry, therefore it is classified according to many parameters.

1. Performance

• Household, up to 3 m 3 /hour
• Commercial, from 3 to 15 m 3 /hour
• Industrial, over 15 m 3 /hour

For household appliances, for example, a heating boiler, optimal choice This is a household regulator.

1. By connection method

There are regulators with threaded and flanged versions. Threaded connection used on pipelines with a pipe diameter of 2” (50 mm). The flange connection is used on large pipelines with a large pipe cross-section.

1. Regulation range

• Wide control range from 1.5 to 12 bar.
• Fine adjustment in the range from 0.5 to 2 bar.

1. Depending on the maximum inlet pressure

• For plumbing systems up to 16 bar
• For systems up to 25 bar

1. To the utmost permissible temperature working fluid

• For cold water with temperatures up to +40°
• For hot water with temperatures up to +70°

1. By type of installed filter element

• Grids with different sizes cells: smaller and larger
• Flask fine filter

How to set the pressure regulator

Setting up models with a pressure gauge is easy. Rotating the adjustment screw provides the required values ​​on the pressure gauge scale. Average pressure – 3 atm. The screw is located on the body and can be easily moved with a wrench.

Devices without a pressure gauge are not adjusted, but are left at the factory settings. However, it is recommended to purchase it additionally. The pressure gauge will allow you to make precise adjustments and protect against unforeseen situations.

Sequencing:

• Close all water intake points: taps, boiler, filters and other devices.
• Open the supply valve to the apartment or building
• Set the required pressure reading on the pressure gauge
• Open the taps where water is consumed and check the pressure reading on the pressure gauge.

Pressure values ​​are allowed to fluctuate within 10%.

Installation of a pressure regulator in the water supply network has become a necessity. This is due to the use household appliances, sensitive to excess pressure in the network. Regulators are required on the lower floors of high-rise buildings. The water supply is carried out from below and in order to ensure normal pressure at the top, high pressure is supplied to the lower floors, which causes equipment breakdowns. And if there is a valve, it will be possible to compensate for the pressure drop.

Operating principle of the pressure regulator water is based on the operation of a membrane box due to the energy of the working medium in the pipeline. Pressure regulators direct action consist of three main elements: valve body, diaphragm block and spring adjuster. A sensitive membrane is rigidly fixed inside the membrane block, which divides the membrane space into two parts. The membrane is rigidly fixed to the regulator cone, thus, acting on the membrane, the valve cone closes or opens the flow area of ​​the regulator and regulates the pressure. The membrane (through the impulse tube (for differential pressure regulators RD122), or direct selection is carried out through the valve body (as with RD102V and RD103V)) is acted upon by the working medium (water, steam, etc.), on the opposite side the membrane experiences a spring force. The directions of the spring pressure and the working medium are determined by the type of pressure regulator: “differential pressure”, “upstream pressure regulator” or “downstream regulator”.

When the adjusted pressure in the regulator is equal to the actual pressure in the system (that is, the system is in equilibrium), the force of the adjusted spring is equal to the pressure of the working medium. The higher the pressure in the system needs to be maintained, the greater the compression ratio of the spring. When the pressure in the system changes, the impulse through the impulse pipeline directly affects the membrane, which in turn affects the regulator cone. When the pressure increases, depending on the type (pressure regulator “before itself” or “after itself”), the regulator opens or closes accordingly.

For example, the pressure regulator behind itself, in the absence of pressure in the system (Fig. 1.1), is normally open. When the pressure increases and exceeds the value set using the setting spring according to the readings of the pressure gauge behind the regulator, the valve cone begins to close until the pressure previously set using spring block, will not be equal to the actual pressure after the regulator.

The downstream pressure regulator valve (Fig. 1.2.) is normally open in the absence of pressure. (The figure shows a diagram of the installation of the regulator on the input branch). Pressure pulses are supplied through impulse tubes from the forward (+) and return (-) pipelines. These pulses act on the membrane, and (depending on the preset pressure drop using the adjusting screw) the change in the pressure drop causes the regulator cone (3) to shift and close or open until the pressure drop reaches the value set on the spring block .

Danfoss ASV-PV, DN15, article number - 003Z5501.

A differential pressure regulator is a special fitting used in piping systems. With this device, the pressure difference of the liquid medium is automatically maintained at the level of preset values. The regulation of differences is carried out by a valve, the flow area of ​​which changes based on pressure parameters.

How are regulators arranged? Design features

Danfoss APT, DN32, article number - 003Z5704.

There are two types of regulators that have fundamental differences:

1. To operate the control device direct action no additional energy source is required, since fluctuations are controlled based on indicators water masses. In this case, the valve opens at the moment of a certain discrepancy with the optimal pressure parameters. This process is carried out at a speed corresponding to the speed of parameter changes occurring in the system.
2. Regulators indirect action can only operate if there is a separately connected power source. The function of measuring elements in such devices is performed by two sensors, through which a signal is transmitted towards the controller. In turn, the control device generates a signal sent to the control valve.

Danfoss ASV-PV, DN20, article number - 003Z5501.

Despite the fact that indirect action products are characterized as high-precision devices, they are rarely used. This is explained, first of all, by the inflated cost and design complexity of such devices.

The automatic direct-acting differential pressure regulator consists of:

• a set point device, which is played by a spring. Some devices are equipped with pneumatic mechanisms or lever-type devices;
• two impulse lines located directly under the valve body itself or built into the pipes;
• meter in the form of a membrane. In some cases, a bellows or piston element is used.

Danfoss ASV-PV, DN15.

Regulator valves are divided into unloaded and unbalanced. In addition, they come in both single and double saddles. Moreover, any of these devices can be connected to the pipeline via a threaded or flanged connection, as well as by welding pipes.

Operating principle of the differential pressure regulator

Currently, membrane-type regulators are predominantly used. Inside such a device there is a chamber with a centrally installed membrane, which is connected to the valve shutter. Due to its displacement to either side, the position of the shutter changes, as a result of which the amount of water masses flowing through the regulator is reduced or increased. The impact on the membrane is carried out through two impulse lines, through which signals are received coming from the supply pipe and the return pipe. The spring, which responds to different pressures, is compressed, thus acting on the membrane, which occupies a certain position.

Danfoss ASV-PV, DN25.

Application area

Modern differential pressure regulators are most often used in water heating systems with hydraulic mode. The presence of such a device allows you to achieve maximum stable pressure in pipes involved in the operation of the heating network. In conditions correct installation devices heating equipment will be reliably protected from zero flow associated with a system restart.

Danfoss ASV-PV, DN15.

Automatic regulators require virtually no maintenance. With relatively simple manipulations associated with setting up devices, they are able to maintain the specified parameters with fairly high accuracy.

Video

The differential pressure regulator is a normally open regulating body, the operating principle of which is based on balancing the force of elastic deformation of the spring and the force created by the pressure difference of the working medium in the membrane chambers of the drive.

Direct-acting differential pressure regulators are designed to automatically maintain differential pressure in heating circuits, hot water supply, ventilation in heating points of heating supply facilities, as well as in other areas of hydraulic systems.

NOMENCLATURE

RDT-Х1-Х2-Х3
Where
RDT- designation of the differential pressure regulator;
X1- design of the regulator setting range;
X2- the value of the nominal diameter;
X3- the value of the conditional throughput.

ORDER EXAMPLE:

Direct acting differential pressure regulator with nominal diameter 40 mm, with throughput 16 m 3 / h, maximum temperature working environment 150°C, with a regulator setting range of 0.2 - 1.6 bar. RDT-1.1-40-16

APPLICATION

DESIGN

MOUNTING POSITIONS

DIMENSIONS

Mounting kit actuator regulator:
for DN 15-100:

• - copper impulse tube DN 6x1 mm, length 1.5 m - 1 piece;
• - copper impulse tube DN 6x1 mm, length 1.0 m - 1 piece;
• - brass nut with internal thread- M10x1 - 2 pcs;
• 
  To ball valve) - 2 pcs;

for DN 125-150:

• - copper impulse tube DN 10x1 mm, length 1.5 m - 1 piece;
• - copper impulse tube DN 10x1 mm, length 1.0 m - 1 piece;
• - brass nut with internal thread - M14x1.5 - 2 pcs;
• - brass fitting with external pipe thread G1/2” (for connecting
  to the ball valve) - 2 pcs;

EXAMPLE OF SELECTION

It is necessary to select a differential pressure regulator.
Network coolant flow: 10 m³/h.
Supply line pressure 6 bar.
Return pressure 3 bar.
Pressure drop across the external circuit of the heat exchanger: 0.1 bar
The pressure drop across the two-way control valve is 0.39 bar.
The differential pressure regulator must be installed on the return pipeline of a heating point with a coolant temperature of 75°C.

1. Using formula (4), we determine the minimum nominal diameter of the valve:
(4) DN = 18.8* √ (G/ V) = 18,8*√ (10/3) = 34.3 mm.
We select the speed in the outlet section V of the valve equal to the maximum permissible (3 m/s) for valves in the ITP in accordance with the recommendations for the selection of control valves and direct-acting pressure regulators of the Teplosila Group of Companies in the ITP/CTP.
2. Using formula (1), we determine the required valve capacity:
(1) Kv=G/ √ Δ P= 10/√ 3.9 = 5.1 m3/h.
We select the pressure drop across the valve ΔP to be 30% greater than what needs to be cut at the heating point ((5.74 – 3)/0.7 = 3.9) in accordance with the recommendations for the selection of control valves and direct-acting pressure regulators of the Teplosila Group of Companies in ITP/TsTP.
3. Select a differential pressure regulator (Type RDT) with the nearest larger nominal diameter and the nearest larger (or equal) nominal capacity Kvs:
DN = 40 mm, Kvs = 16 m 3 / h.
4. Using formula (2), we determine the actual drop across the fully open valve at a maximum flow rate of 10 m 3 /h:
(2) Δ Pf = (G/Kvs) 2= (10/16) 2 = 0.39 bar.
5. Select the setting range of the differential pressure regulator: dP = dTO + dРК = 0.1+0.16 = 0.26 bar. From the table for selecting the range of the differential pressure regulator, select version 1.1 (0.2-1.6 bar).
5. Using formula (5) and the value of Рсаs from Table 2 of the recommendations, we determine the maximum pressure difference that the regulator can “extinguish” on itself with the required setting to maintain a pressure difference of 0.26 bar and a coolant temperature of 75°C:
(5) Δ Plim = Z*(P1-Pus)= 0.55*(5.74 – (–0.61))=3.49 bar.
6. Check the value of the maximum difference on the circuit design: 5.74 – 3.0 = 2.74 bar 7. Order nomenclature: RDT-1.1-40-16.

DEVICE

The device of the differential pressure regulator is shown in the figure below, the list of parts is in the table

The regulator valve is normally open when there is no pressure. Pulse high pressure adjustable differential is supplied by an impulse tube (connected to the upper chamber of the drive 02 from the controller side 03 to the fitting “+” pos. 14) to the membrane pos. 11. Pulse low pressure supplied by an impulse tube (connected to the lower chamber of the drive 02 valve side 01 to the fitting “-” pos. 16) under the membrane. Changing the regulated pressure difference above the set value set using the spring pos. 18 (22) in the set pointer 03 , leads to a shift of the rod pos. 21 and closing or opening of the valve plate pos. 7 01 until the value of the controlled differential pressure reaches the value set on the setpoint 03 .

REGULATOR INSTALLATION

It is recommended to install a filter in front of the regulator.
At the point where the pulse is taken, it is necessary to provide a manual valve that allows you to turn off the pressure from the pulse tube.
To avoid contamination of the impulse line, it is advisable to take the impulse from the top or side of the pipeline.
It is advisable to provide manual shut-off valves before and after the regulator to allow Maintenance and repair of the regulator without the need to drain the working fluid from the entire system.
Install two fittings from the regulator mounting kit on the supply and return pipelines according to the regulator connection diagram in places convenient for connecting impulse pipes.
Install pressure gauges close to the pulse intake points (fittings).
When installing the regulator on the supply pipeline, install a pressure gauge in front of the regulator.
When installing the regulator on the return pipeline, install a pressure gauge after the regulator. Connect impulse tubes fitting “+” of the regulator with a supply pipeline and fitting “-” of the regulator with a return pipe