Pressure reducer for gas tank: operating principle, design features and replacement instruction

Agree that when designing and installing gas equipment, a parameter that deserves special attention is the working pressure? Since only by observing the required values ​​and constant adjustment of this characteristic, safe operation of the gas system is possible.

The pressure regulator for the gas tank is used to stabilize and lower the pressure of the gas in the storage tank, therefore the regulator is an integral part of the system: “gas tank - gas consuming devices”.

Self-installation or replacement of a gas reducer in an autonomous gas supply system at home requires certain skills and knowledge. You need to know what it consists of and how the control device works. Therefore, we propose to deal with the principle of operation of the gearbox, the intricacies of adjustment and the nuances that arise when replacing it.

Purpose and arrangement of the gas tank gearbox

To supply gas to cottages, cottages and private homes are used gas holders. Despite this, a gas reducer with a pressure gauge and a safety valve is an integral element of the system designed for storage and supply to blue fuel.

The gas reducer performs a function similar to that of a stabilizer in an electrical network. It stabilizes the gas pressure coming from the tank to the equipment. In addition, his task is to maintain a certain pressure obtained at the outlet of the tank throughout the engineering network.

No need to save on the stabilizer. The device for the gas tank must be of the highest quality, since 80% of the problems in the system arise due to gearbox failures

The operation of any gearbox is aimed at lowering the pressure of the liquefied gas, so all pressure stabilizers have the same elements:

• housing;
• two gas chambers;
• inlet and outlet fitting;
• main and auxiliary springs;
• pressure reducing and safety valves;
• a membrane;
• gear drive with pin;
• one or two manometers;
• adjusting screw.

Gearboxes may differ in weight and dimensions, body shape and throughput.

The principle of operation of the stabilization device

Modern pressure reducers for a gas holder, work on the principle of reverse action. Gas coming from the intake rod tends to close the pressure reducing valve.

The adjusting screw compresses the main spring and when air comes out of the working chamber, the flexible membrane understands the transmission disk with the pin up. At this moment, the pin compresses the return spring, diverting the pressure reducing valve from the seat, gas enters the working chamber.

Two-stage gearboxes are less prone to “freezing”, therefore, such devices must be installed on gas tanks in regions where extremely low air temperatures are observed

After moving the substance into the low-pressure chamber, gas is released into the system. As a result, the spring relaxes, the transfer disk with the pin lifts the valve, gas from the upper chamber enters the low-pressure chamber, the process repeats.

If the gas discharge decreases, the pressure in the chamber will increase, the spring will take a “closed” position, the valve will lower into the seat, the gas supply to the pressure reducer and the low-pressure chamber will stop.

To stabilize the pressure of the gas in the gas tank, two-stage gearboxes are used. The fuel in such regulators, before entering the exhaust fitting, goes through two stages of reduction.

To increase the life of the gearbox, it is necessary to minimize the contact of the membrane and other elements with moisture. To do this, at the installation stage, decorative or standard protection is installed above the tank

Two stages of the gearbox provide maximum stability of the outlet pressure, therefore they are safer during operation.

In addition, two-stage devices are resistant to freezing, so they provide a continuous supply of gas in summer and winter. If the gearbox is still frozen, we recommend that you read our other article, where we described in detail how to fix this problem. Read more - read Further.

How to adjust the gas reducer?

The factory settings of the gas outlet pressure in the gearboxes may differ from the optimal one for this network, therefore, direct adjustment of the working pressure in the gearbox of the gas tank occurs during its installation. The physical quantity depends on the tension of the main clamping spring, which changes when the position of the adjusting screw changes.

In two-stage stabilizers, the adjusting screw can only be located on the first stage of the gearbox. Such devices include models: Cavagna Group type 524, GOK PS 16 bar POL x IG G1 / 2 PSK CIS, SRG 7.5 kg / h.

In some more expensive models of the Italian company Cavagna Group, German GOK, American Fisher, the second stage of the regulator is also equipped with an adjusting screw.

Reducers for gas holders are presented on the market, in which one working unit intervenes a combination of two reduction stages. It is equipped with the same regulatory and protective systems, provides an output pressure of 37-50 mbar

Both stages of the high pressure regulator can be selected separately, then the complete set of stages, the user can choose independently. In this case, gas reduction devices connected to the complex valve always have a pressure adjustment screw, and the second stage can be either with a screw or without a screw.

Popular Cavagna Group type 992, 998, 998-4 type variable speed gearboxes are popular.

The first stage of pressure control occurs on the valve for the selection of the vapor phase of the gas, using the built-in pressure gauge. Further gas enters the gearbox chambers. If they do not include control devices, pressure gauge set directly on the outlet pipe.

In almost all gearboxes for a gas holder, the outlet pressure is adjusted using a screw. The adjusting screw is turned with a key through the hole located under the removable gear cover.

Turns clockwise increase the output pressure, against - decrease.

In addition to the pressure gauge and the screw, the safety valve also supports the optimal state of the system. If the pressure in the chambers rises above normal, then through it there will be an emergency discharge of gas into the atmosphere

At the outlet of the tank, after the valve for selecting the vapor phase of the gas, the substance enters the first stage of the gearbox, the stabilizer converts a high pressure in the range from 0.2 to 4 bar, depending on the model of the device.

The second stage reduces the stable pressure necessary for the operation of the connected equipment, equal to 10-200 mbar.

Regulator Replacement Instructions

Two-stage gearboxes are connected to the vapor phase selector valve using a threaded fitting and union nut. The type of thread at the gearbox inlet depends on the type of thread at the valve outlet.

If at the time of purchase the nature of the connection was not taken into account, an appropriate adapter will be required. Device connection with gas hose, is carried out through a threaded outlet on the gearbox, using an adapter or union nut.

To replace the stabilization device, a gas key is required. If the connection is rusted, then to remove the gearbox you will need two adjustable gas wrenches.

Replacing or repairing a gas gearbox is often done in winter, when condensation forms at the junction of the valve and gearbox. To prevent such malfunctions, it is necessary to provide for electric heating at the stage of installation of the gas system

To replace the gas reducer, the following sequence of work must be performed:

1. Shut off the gas supply with the valve located on the gas vapor extraction valve.
2. Unscrew the metal hose.
3. Unscrew the union nut connecting the valve and stabilizer.
4. Remove gearbox with connecting hose.
5. If the stabilizer cannot be repaired, then twist the bellows hose.
6. After cleaning the ice, repairing or replacing, the regulator should be screwed to the complex valve with a nut.
7. If the device was disconnected from the inlet, it is necessary to gradually connect the gas hose, first to the gearbox, then to the trunk.
8. After fixing the connections, you can turn on the gas supply.

When starting the fuel into the system, after replacing the fittings, it is necessary to check the outlet pressure, it must be within acceptable limits and be suitable for the operation of a heater, stove or boiler.

With proper installation and normal operating conditions, the regulator, as a rule, lasts at least 10 years.

For high-strength sealing of threaded joints, it is recommended to use a blue anaerobic sealant. The material should not be used at low temperatures due to the increased polymerization time, but if the compounds are treated in the summer, they can be 100% sealed

Diagnose problems with the stabilizer using a level gauge and pressure gauge on the tank. If the devices show that there is enough gas, but there are interruptions in the network, then one of the problems with the gearbox is to blame.

In this case, the device can be taken apart and dried. This will help solve the problem, but temporarily. If you install a new gearbox and protect the device from moisture, you can forget about interruptions in the system.

In order to avoid possible problems with the gearbox in the future, it is also important to take care of the correct installation of the gas tank on the site. You can read about how to do this correctly. here.

Conclusions and useful video on the topic

So the gearbox is adjusted using a differential pressure gauge:

This video shows how to eliminate minimal condensate freezing in the regulator:

How to remove, disassemble and clean the gearbox, as well as to prevent flooding / freezing, will be discussed in the following video:

Pressure reducer for gas tank, reduces vapor pressure of blue fuel, maintains its stable value in the engineering network. Each regulator is equipped with a safety relief valve that discharges excess gas when there is a dangerous increase in pressure at the fuel outlet from the safety circuit.

Therefore, it is the reducer that is the main mechanism for preventing emergencies in an autonomous gas supply system.

In the event of a malfunction, it is necessary to know how the device works and how to replace an unusable device. Therefore, the rules for replacing the gearbox will definitely come in handy for owners of private houses that have been gasified from a gas tank.

If you had to install, change the gas reducer or adjust the gas pressure in the autonomous system. If you know any subtleties and nuances that arise during the replacement of the stabilizer - be sure to share your experience and relevant photos with readers in the block below.