Why the gas cylinder gearbox buzzes: what to do if the gas pressure regulator is noisy

Amir Gumarov
Checked by a specialist: Amir Gumarov
Author: Alesia Markova
Last update: November 2019

The reducer is an obligatory component of the connection scheme for tanks with liquefied and compressed gas mixtures. They are installed on gas holders, single cylinders and balloon installations to stabilize and bring to standard values ​​the pressure of the gas supplied to household equipment, welding torches and heaters.

It happens that during operation the device for ensuring stable pressure begins to make noise. We will explain why the reducer is buzzing on a gas bottle, we will analyze why the sound appears. We will show you how to eliminate violations in the operation of the device, which can be determined “by ear”.

In the article we presented, the types of gas pressure stabilizers and their design features are described in detail. Methods of restoring full working capacity are given. Our recommendations will help home craftsmen cope with repairs on their own.

Gas Pressure Reducing Devices

The need for the use of reducers is due to the difference in gas pressure in the tanks intended for storage and dosed supply of gas to the devices, and the operating parameters of the pressure required by these devices to perform their duties. When selecting fuel from a closed tank, the pressure of the gas mixture must be reduced by a dozen or more times.

Reducing the pressure of liquefied or compressed gas sweep to performance is the main work of gearboxes. In addition, they automatically maintain the gas flow pressure within the limits required for normal operation. And they also protect the gas tank from the back impact possible with the activation of the flame.

With the help of gearboxes, gas pressure is regulated. They can be configured to supply a gas medium with pressure parameters that are acceptable literally for any type of household and industrial equipment. Despite an extensive list of functions, structurally, all types of devices are simple, and even work on a similar principle.

Types of gas reducers

In order to understand why a gas cylinder began to make noise, it is necessary to study its structure. Let’s figure out which types of gearboxes to adjust and stabilize the pressure of gas mixtures used in everyday life.

Classification is performed according to the following grouping criteria:

  • Principle of operation. Gearboxes are direct and reverse. The former reduce pressure in the tank itself and in front of the nozzle connected to the gas equipment. The second - first lower the pressure in the cylinder, then at the outlet of it.
  • Destination. There are network (C), balloon (B) and ramp (R) devices. The network ones are mounted on gas supply pipelines, the ramp ones are mounted on balloon installations, which ensure the supply of gaseous fuel in large volumes. For domestic conditions and one-time welding work, balloon models are suitable.
  • Type of reducible gas. Pressure stabilizing devices are installed on all types of gas cylinders. To accurately select the necessary gearbox, they are painted in the colors of the cylinder. For tanks with propane they produce red, for tanks with oxygen blue and for tanks with acetylene - white.
  • Regulation scheme. The installation of the operating pressure parameters can be performed and adjusted mechanically, such devices are single-stage (O) and two-stage (D). Gearboxes with pneumatic pressure selection are only single-stage.
  • Connection. Reducers are produced for installation on cylinders with combustible and non-combustible gases. The devices are connected to containers with oxygen with union nuts with a right-hand thread, to cylinders with a propane-butane mixture - nuts with a left-hand thread. The acetylene reducer is connected using a clamp and a thrust screw.

Let's analyze and study the design with the principle of operation of gas reducers, traditionally used in everyday life to adjust the flow gas mixture to appliances.

Design features and principle of operation

Summer residents and owners of small private houses to supply gas to stoves, heaters and heating boilers use one of the most common gas reducer models in everyday life: NZGA RDSG-1-1.2, popularly known as the “frog”, or its analogues.

The one-stage model is extremely simple. Reduction is carried out by a membrane pressed from the outside by a spring. The membrane limits the path for gas to move through the cavity of the device so that a stream with a predetermined volume and standard pressure enters from the outlet in the gas hose or pipe.

If the pressure in the cavity of the gearbox rises, the valve and washer associated with the membrane rise and cover the inlet. This is how pressure stability is ensured. And if necessary, to change the operating characteristics of the pressure, these control elements are displaced, increasing or decreasing the inlet section.

The design diagram of the elementary model of the gearbox
The frog-type pressure regulator usually begins to make noise due to damage to the membrane or loss of tightness if it is displaced

In slightly more complex devices, for example, in the model FL92-4 PS, the reduction is carried out by a valve that restricts the flow and thereby forms the pressure required by the devices.

The membrane in such devices does not directly participate in the formation of pressure, but only reduces the initial parameters. On it, on the one hand, a gas flow acts, on the other hand, a coil spring, which is pressing from below.

Gas pressure regulator with adjusting screw
A pressure gauge is required in the gearbox connection schemes with the ability to adjust the gas pressure. It is needed to control the set parameters and monitor the state of the gas mixture in the tank

These devices exhibit some pressure loss as the blue fuel is consumed in the gas mixture tank. Therefore, the housing has an adjustment screw that allows you to adjust the performance. In order not to make a mistake with the adjustment, such models are equipped with pressure gauges.

Reverse gear reducer
In more complex models of gearboxes, the pressure characteristics of the gas mixture required for operation are set by both the bending diaphragm and the opening valve

In devices of the third type, for example, TECH CONTROL of the OX OR-128 series of the Svarog 95255 brand, pressure characteristics are reduced and stabilized due to the simultaneous movement of both the valve and the membrane.

The gas flow entering the cavity of the gearbox is on the one hand held and controlled by a valve, and on the other hand, by a membrane supported by a spring with a transfer disk.

Gearbox with two pressure gauges
Two pressure gauges are used to control pressure parameters in control devices with a working valve and a membrane. Mount them at the inlet and outlet of the gearbox

The operation of gears of the third type should be controlled by two pressure gauges supplied at the input and output of the device. They also tend to change the working pressure at the outlet of the gearbox as the gas source is empty.

Malfunctions and repair operations

We examined the structure of typical models of gas reducers and made sure that there are no technically complex assemblies in the design.Everything is so elementary that it’s not necessary to turn to gas workers to repair devices. Simple repair operations can easily be done with your own hands.

You just need to figure out in advance what to do so that the gas cylinder reducer stops buzzing.

The causes of noise in a reduction device include:

  • Deformation and damage to the elastic working element (membrane) of the device, which is often caused by excess pressure of the gas mixture at the outlet of the cylinder or gas tank.
  • Incorrect operation. Most often, due to inaccurate and illiterate actions in the process of self-regulation, the spring or the membrane is damaged.
  • Preparation for supplying low-quality, poorly cleaned gas mixture to gas appliances.

Often, at the initial stages of the appearance of noise in the gearbox, it is enough to simply adjust the factory settings. However, we note that the “frog” refers to unregulated devices; in any case, it will have to be repaired. Repair is carried out by banal replacement of damaged parts: a membrane, an end face of a bypass valve or a spring.

How to change the membrane?

To replace the membrane, it is better to use a repair kit, commercially available from the manufacturer of the gas reducer. This elastic element belongs to the abradable and periodically worn category, because manufacturers of expensive gearboxes supply replacement parts for sale.

The internal structure of the gas reducer
In order to competently carry out repairs and change damaged parts, you need to thoroughly study the device using the technical documentation attached to the product

If you do not have a membrane for your gearbox brand, then you need to find out the following characteristics:

  • Dimensions of the rubber-fabric diaphragm (membrane).
  • The thickness of the oiled elastic web of which the membrane is made.
  • The location of the fixation points around the circumference of the membrane.

Data can be found in the technical documentation for the device or obtained as a result of trivial measurements.

Gearbox Replacement Options
One of the typical causes of a malfunction in the gas pressure regulator from a cylinder is a loss of tightness in the area of ​​the membrane or its damage

It happens that the sound in the gearbox does not appear due to a torn or deformed membrane, but because of a loss of tightness between it and the body.

In this case, the gearbox is quite simple to sort out. Before reassembling, the parts of the housing that are in contact with the membrane must be lubricated with sealant, then the components must be connected, making the diaphragm fit perfectly to the rigid base.

How to fix a reducing spring?

The process of replacing a compression valve or spring diaphragm is no more complicated than installing a new diaphragm. In the design of gearboxes used in schemes with gas cylinders, reducing springs of the first degree, Ø 15,5 with the number of turns 12-14 pieces are used.

Direct type gas mixture reducer
Springs are used in the construction of all types of gas gears. They are in elementary unregulated “frogs” and in more complex devices with adjusting devices

The spring during operation can crack corny, lose firmness and elasticity, stretch. Due to any of these malfunctions, the membrane and the inlet valve will not be able to balance their force, i.e. control over the flow of gas into the gearbox will be lost.

In the event of a spring breakdown, it is replaced with a completely similar part. If it is just a little stretched, the problem is solved by installing a gasket. The thickness of this seal is selected based on the situation, measuring the necessary distance to reduce the fact.

How to change the reducing valve?

This work is more serious than the previous steps. An important functional part of the gearbox is connected with an adjusting screw, the position of which determines the gas pressure. A spring compresses it, which with excessive force can easily be damaged.

In addition, the valve may not be able to cope with the duties due to damage or deformation of the end of the tube resting on it. The course of the rocker arm may be disturbed, the movement of which is prevented by any shifted or damaged part. Still malfunctioning of the valve are observed due to wear of the gasket.

Compressor gearboxes
In the device of pressure regulators for compressed gases used in everyday life mainly for gas welding and metal cutting, similar structural elements are used

Naturally, in order to restore valve operability, it will be necessary to disassemble the gear housing. Mobility of the beam is ensured by replacing the displaced parts. If necessary, grinding of the edge that interferes with free travel is performed.

It often happens that all violations in the operation of the valve are associated with only a leaky gasket. Because of it, the elements of the device slightly change their position, but even fractions of millimeters are reflected in the functionality of such a sensitive device. "Treated" by installing a new gasket.

If the end of the tube is damaged, you just need to grind it. If the tube or rocker is seriously damaged, it is better to change them. Replacement is carried out using repair kits produced for the maintenance and repair of gas valves.

Conclusions and useful video to the topic

The device and the principle of operation of the gearbox for the liquefied gas mixture will clearly present the following video:

The video introduces the recommendations for choosing a frog-type gearbox:

Video presentation of propane gearbox with pressure gauge:

It should be remembered that the inspection of the technical condition and repair of fittings for gas appliances should be carried out by employees of gas services involved in the supply of blue fuel and equipment maintenance. However, the simplest operations can be handled independently. This happens, for example, if it is difficult or impossible to call a gasman to the cottage.

Want to talk about how to repair a gas pressure regulator with your own hands? Do you know the intricacies of the process that can help website visitors? Share them, useful information and pictures on the subject of the article in the block below.

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