DIY propane cylinder valve repair

How can a gas leak from a high pressure gas cylinder valve or a system connected to a cylinder be repaired?

An example of a situation. You filled the cylinder at the station, arrived home, connected the reducer, as well as the hoses, tightened the hexagon of the reducer on the cylinder, opened the cylinder valve - and you understand that the gas is poisoning somewhere in the upper part of the flywheel. If, for example, carbon dioxide is filled into a cylinder, you will immediately smell a foreign smell.

Attention! We warn you that the repair of cylinders must be carried out by specially trained and certified specialists! We strongly do not recommend that you carry out your own repair of high-pressure cylinders, unskilled intervention can lead to tragedy. When carrying out repairs described below in the text, you yourself are responsible for the manipulations.

It happens that it is necessary to work, but there is a small malfunction, which is quite permissible to fix it yourself.

So, in order to eliminate the breakdown described above, it is necessary to do the following (valid only for a valve of the VK-94 type and its modifications):

• First, take a 27 mm wrench and try to tighten the nut shown in the photo, clockwise... In most cases, this helps.

If, when trying to open the flywheel, the gas starts to poison again from its upper part, it is necessary to unscrew it counterclockwise until it stops, the leakage should stop.

If the previous manipulation did not help, then it is necessary to do the following (valid only for the VK-94 valve, the procedure should be carried out only with knowledge of the matter):

• Unscrew the nut under the flywheel counterclock-wise and remove it from the cylinder.

• Then, using a 10 mm wrench, unscrew the nut located at the top of the flywheel.

• Remove the stem from the nut - a stuffing box gasket is installed inside it.

• If the cylinder is not of the first freshness (and there are 90% of those in our country), then the gasket will be in an appropriate, "shabby" condition. To eliminate the leak, you need to make the same new gasket made of fluoroplastic (GOST 15180-86) or paronite (GOST 481-80). You can try to make a lining from a plastic canister, but this is short-lived and ineffective. The inner hole of the gasket should be no more than 8.5 mm in size, the outer, respectively, in the size of the inner diameter of the nut. After replacing the gasket, the stem should sit tightly, you will need an additional tool to hammer it in (hammer, flat part of the adjustable wrench, etc., etc.) and thus put it back in place. Then the flywheel is installed back and screwed on with a nut.

Note... The flywheel nut is not tightened to the stop, but so that the spring is tensioned, but not clamped. Otherwise, the flywheel will not rotate.

• Put the assembly back on the cylinder and tighten with a nut clockwise with a 27 mm wrench not up to the stop (with a force of 5-7 kg).

Note. Such procedures can be performed only with the VK-94 valve and its modifications.

The valve of the VKB type cannot be disassembled. If there is gas in the cylinder, even residual pressure, it is strictly forbidden to open the nut. Because besides her, the pressure in the cylinder holds nothing! SUCH CYLINDER CAN ONLY BE REPAIRED EMPTY.

There is a small inspection hole on the back of the VKB-type valve. In the event of a breakdown of the diaphragms that are inside the valve, gas begins to flow from this hole.If, when screwing on the reducer and opening the valve, gas does not come out of this hole, then the valve is in good condition and is allowed to work.

VKB is usually installed on cylinders with helium, for all other gases, as a rule, VK-94 is installed.

If a cylinder is out of date and needs to be inspected or replaced, pay attention to the following things:

• The wall of the cylinder should not have dents, rotting shells with a depth of more than 1 mm;
• Pay attention to the date of manufacture of the cylinder, the passport must be readable on it;
• Pay attention to the valve, it must not be knocked off (so that it can be unscrewed).

You must be logged in to post a comment.

I bought several 50-liter cylinders from my hands. I never dealt with them, I didn't really check them, and one got defective. The crane turns back half a turn and locks. Although, judging by the weight, there is a decent amount of gas left in the cylinder, it does not come out. It turns out that the crane is broken.
How to fix it? After all, if you break something, the gas will start flowing and it will not be stopped. There will be a boom

SergAG wrote:
It turns out that the crane is broken.
How to fix it?

Gas vapors will still be decent, there is a chance to spark when replacing, and then - VAC.
You don't need to save gas, you need to save your life.

2Vottakoy, I don’t feel sorry for the gas, I just don’t know what to do with it. Any valve repair will begin with the gas outlet. If there were leftovers, then half a bottle is at least.
I am not familiar with the valve design. What can get wedged in there, and can there be a "depressurization" of the cylinder if I stupidly apply force in the hope of unscrewing the tap? If you read the link 2Alex___dr, then the valve itself on the cylinder sits oh-ho!

I have a counter screw on the side of the valve that prevents the valve from unscrewing. Look carefully, suddenly you too. Then unscrew it and take it out and the valve will start to rotate. I do not know what else can go crazy, tk. the thread is through there. If only the thread was fucked up to horror.

SergAG wrote:
If there were leftovers, then half a bottle is at least.

Drive out of town, to a well-ventilated place and only there to do something.

PS I set up the software at the gas station - and so, 1 kg of gas released into the air gives a hefty cloud.

SergAG Buy a plug, they are special for gas cylinders, put it on, and still try to turn the valve wing by force, drive it, here and there. If it breaks down, release the gas on the street, slowly, and replace the valve. If it breaks down so that the gas still remains closed, try to change the cylinder in the exchanger. Well, or using a sparkless tool, change it yourself.
In principle, the ignition of gas through a small leak is not scary, there will be no explosion, it will simply burn like a burner. The flames can be knocked down easily. It's just that all this is unexpected, people usually run away in a panic, and the cylinder heats up, the leak grows, the cylinder heats up more and explodes.

You can go somewhere in the forest, light a fire, throw a balloon, quickly run away and watch how it explodes))) For memory, shoot it on video.

Gas cylinders contain certain gases and their mixtures under high pressure. The valves are designed to maintain this pressure in the safe area of ​​the cylinder, as well as to control the flow rate of the contents. We will talk about their structure, problems and replacement rules in this article.

A modern gas cylinder complies with GOST 949-72 and is a durable all-welded element made of carbon or alloy steel. According to the standard, the wall thickness of the cylinder cannot be less than 2 millimeters. In order for the gas inside to press equally on the upper and lower parts, they are made concave and convex. The cylinders themselves, depending on the substance in them and its quantity, can have different sizes, shapes and colors. But one thing remains unchanged - any gas cylinder must necessarily have passport data assigned at the factory.In the upper part there is a threaded neck into which the valve is inserted.

The design of the valves is extremely efficient and allows them to be the same regardless of what exactly the cylinder is filled with. However, the content usually affects what color a given element will be painted at the factory for the purpose of better identification:

• Red color - propane-butane valve;
• Blue color - oxygen valve;
• White - acetylene valve.

Look at the label first. Its main inscription should occupy two-thirds of the total area of ​​the label and the height of the letters should be exactly 6 centimeters. These are the standards. The following is mandatory: container number, manufacturer's trademark, empty weight, indication of cylinder capacity, date of issue and inspection (past and next), test hydraulic pressure, etc.

• Valve malfunction - the flywheel does not turn or other problems are present;
• Corrosion, dents or other damage to the body of the cylinder and valve part;
• The date of the survey is overdue;
• Gas is felt in the air;
• A crooked or damaged cylinder shoe;
• There is no plug on the fitting.

Important! In no case should you use the contents of the gas cylinder to the end. During the termination of operation, the residual pressure inside should remain at the level of 0.5 kgf / cm2.

As we said above, the valve in the propane cylinder is practically no different from that on the oxygen or other gas container. All of them have approximately the following construction:

• Robust steel cylinder with three holes. Each of these holes is provided with a thread and is intended for screwing onto a cylinder, mounting a plug and a nut from the valve, which is adjusted in the upper cylindrical part;
• Flywheel mounted to the valve stem by means of a nut;
• Locking device with stem and by-pass valve. This valve transmits torque from the flywheel. The pressure that this part can withstand varies from 15 to 190 atmospheres;
• Gaskets designed to maximally seal the connections between all parts of the assembly.

The purpose of the test is to monitor for gas leaks. For this, soap foam is applied to all joints, after which the valve is opened and the foam is monitored for the formation of bubbles there. It is necessary to carry out the operation twice, applying the soap solution again.

The cylinder itself is one-piece, and something is unlikely to break there. Therefore, most of the malfunctions concern gas valves.

Important! Working with gas cylinders is potentially hazardous. Moreover, there is a strict ban on the removal of cranes in artisanal conditions. Remember that it is best to entrust this business to professionals, and you need to start independent actions only if you are confident in your abilities, willingness to strictly follow the rules, and, of course, the urgency of the repair. If there is even the slightest opportunity to transfer this task into the hands of a specialist, it is strongly recommended to use it.

In general, the gearbox, which is non-separable, must be replaced every six years. As for the hoses, they must be reinforced and must be inspected no earlier than once every six months when replacing the cylinder.

• Do not open the valve too quickly. In this case, the head can be electrified by the gas jet, which will lead to an explosion;
• The safety valve must be checked for functionality every quarter;
• Periodic gas leak check;
• In the case of propane-butane, more than one cylinder should not be allowed at the workplace.

The balloon valve has a special function of regulating the gas supply and ensuring tightness and preventing its spontaneous leakage. That is why the requirements for the maintenance of such an element are also high.

Before considering in detail the stop valves, it is necessary to clarify that it is just a part of a container for transporting and storing various gases under pressure. Cylinders are made of carbon or alloy steel in accordance with GOST 949-72. They differ among themselves in color and volume, but the device is the same. So, a gas cylinder consists of a valve, a seal, a thread and a seamless tank with the passport data assigned by the manufacturer to be stamped on it.

The valves are divided into several types, depending on what the cylinders are filled with: liquefied gas, oxygen or propane-butane. At the same time, there are practically no distinctive features of the structures, only the marking of the valves according to GOST differs:

• Blue color - to indicate the oxygen valve;
• Red - propane-butane;
• White - acetylene, etc.

All locking devices are arranged in almost the same way and consist of the following parts:

• Steel body in the form of a tee, each side of which has a thread: the lower one - for screwing onto the cylinder, the upper cylindrical one - for the valve nut, the side one - for the plug;
• A shut-off part, which includes a check valve and a stem, which transfers the torque element from the flywheel to the valve;
• A flywheel, which is connected with a nut to the valve stem.
• Sealing gaskets, which are located between all parts and provide additional reliability of this design.

A distinctive feature of this locking device is the ability to withstand a constant pressure from 15 to 190 atmospheres.

Before proceeding with the replacement of this equipment, you should carefully read this manual and strictly follow all safety rules. And remember that gas in any quantity does not tolerate neglect.

• Before dismantling the valve, it is possible, as preparatory work, to unscrew the shut-off assembly for the escape of gas residues. This should be done in a well-ventilated area or outdoors;
• After that, the part needs to be warmed up a little. This will make it much easier to unscrew the valve by hand or with an adjustable wrench. This procedure is absolutely safe, the main thing is not to overdo it with heating.
• Having removed the failed valve, be sure to prepare the shut-off assembly for installation. To do this, a special seal is applied to the conical fitting located at the bottom of the housing; you can use a fluoroplastic tape;
• The final step is screwing in the new valve with a torque wrench to control the applied force.

Do not forget to make an appropriate note about the procedure in the passport of the gas cylinder.

Quality control of the performed procedure and the absence of leakage is carried out as follows: soap foam is applied to the docking site and the valve is slowly opened. The absence of leakage is characterized by the absence of bubbles, if they are still there, you need to immediately screw the valve back and check all the connections again.

Do not forget that your life is in your hands! Be careful and follow all fire safety rules!

The article describes the device of cylinders, malfunctions and ways to eliminate them. Designations for gas cylinders.

Gas cylinders have firmly entered our life, despite the prevalence of main gas, gas cylinders have not lost their relevance. Nothing is forever under the moon. And the metal cylinders break.

Gas cylinder repair is a demanded service among users of bottled gas. It is cheaper to repair a cylinder than to buy a new one.

Gas cylinder device:

• cylindrical body with upper and lower bottoms;
• a valve screwed into the cylinder body;
• a cap that protects the valve from mechanical damage;
• a neck ring, a cap is screwed onto it;
• pressure stabilization reducer;
• a shoe that holds the cylinder in an upright position.

• valve body;
• locking mechanism;
• flywheel.

There are breakdowns that are prohibited from being repaired for safety reasons. In such situations, they hand over the broken cylinder for scrap or exchange it for a new or repaired one.

Anyone who, due to professional or everyday needs, deals with gas equipment, need to know when a gas cylinder needs to be repaired. The use of various gases has become widespread in all spheres of the national economy - in industry, construction, agriculture and everyday life. Therefore, an important aspect of observing safety measures and preserving the health of employees and the public is knowledge of the signs of malfunctioning gas cylinders. All types of malfunctions can be divided into recoverable and non-recoverable. In the event of a recoverable malfunction, the cylinder must be repaired. In the presence of fatal malfunctions, the cylinder should be disposed of in compliance with all safety measures.

Removable malfunctions include:

• visible damage to the valve and cylinder pressure gauge, incorrect operation of these devices;
• change in the position of the "shoe" or damage to it;
• wear or damage to the thread on the neck of the cylinder;
• if you suspect a gas leak from the cylinder;
• if the color of the cylinder is significantly damaged.

Fatal malfunctions that make further operation impossible are considered to be significant damage to the surface of the cylinder - cracks, dents, chips, cracks in the weld, swelling, as well as the irrevocable loss of marking and passport data.

The final decision regarding the damaged cylinder is made by a qualified technician after inspection.

Often, the repair of a gas cylinder consists in replacing damaged elements, such as a pressure gauge, valve, valves or diaphragms, replacing a threaded connection. In some cases, flushing the inside of the cylinder and checking the inside surface for corrosion damage is required. The same procedures are included in the mandatory periodic warranty inspection of the cylinder with the subsequent issuance of a certificate. Anyone who uses propane cylinders in everyday life should be sure to know the signs of gas leaks and other types of malfunctions for their timely identification and elimination. At the same time, we must not forget that the repair of propane cylinders is an extremely difficult and dangerous business that requires great skill and special equipment. It is highly discouraged to do such work at home. Of all the possible types of repairing gas cylinders for do-it-yourself, only the restoration of the cylinder painting is possible. In this case, care should be taken not to damage the labels and markings on the cylinder. In other cases, you should contact the manufacturer for warranty repairs or a specialized workshop.

A gas cylinder is a device for storing and transporting gas mixtures. For safe use, gas-containing devices are equipped with mechanisms responsible for the stability of the gas supply.

Mechanisms tend to wear out and break. Light breakdowns are repaired by hand, serious ones are repaired in specialized workshops. Such workshops are equipped with measuring instruments and a tool base for the repair of gas cylinders.

When closed, the container is sealed and does not emit foreign odors. A gas leak indicates a malfunction of the gas device. Depressurization is checked with an aqueous soap solution.

Types of malfunctions and repair of propane cylinders:

1. Gas valve defective.
2. Defective gas pressure stabilization reducer.
3. Housing malfunctions.

In order to determine the operability of the valve, the connections are lubricated with soapy water.If the bubbles inflate, then the valve is faulty and needs to be repaired.

Gas equipment is repaired in well-ventilated areas in compliance with safety regulations.

Before unscrewing the valve, the remaining gas mixture is drained.

• after emptying, the valve is unscrewed; to facilitate unscrewing, the valve is moderately heated;
• the valve is unscrewed with a gas wrench;
• after unscrewing the valve, the liquid phase of the gas mixture is drained;
• the conical nipple is sealed with a seal or fluoroplastic tape;
• a new fitting is screwed in with a torque wrench, for steel valves the force is 480 Nm and 250 for brass valves, the torque wrench will not allow to break the thread;
• the fact of replacement is entered in the cylinder passport, the date of valve replacement is indicated.

The valve is not a collapsible mechanism, it must be replaced. Replacement frequency - once every 6 years.

A malfunction of the gearbox manifests itself in its depressurization and gas leakage when the valves are closed. With these symptoms, the gas supply valve does not tightly close the supply gas passage to the pressure stabilization chamber.

In cold temperatures, the gearbox freezes and gas does not pass through it. To troubleshoot:

• turn the valve;
• the reducer is thawed with hot water;
• remove the hose;
• blow through the gearbox and hose;
• check the hose for leaks;
• after troubleshooting, reassemble in reverse order.

The hose is checked for integrity once every 6 months. The gearbox is checked once every 1 year. Scheduled replacement of the gearbox once every 6 years. Serious breakdowns are repaired in the workshop.

To identify a malfunction, the body is checked for sealing. Examining the body, they reveal the presence of cracks, chips, defects, seam rupture. On inspection, the cylinder is washed and treated with solutions to detect defects and the presence of dangerous corrosion.

Rejected cylinders are disposed of or deliberately broken so that they do not end up in further circulation. A damaged housing is explosive, so it must not be used.

All types of repairs to propane cylinders are entered in the cylinder passport, and a certain note is made.

List of designations indicated in the passport:

• - "ЗВ" or "ЗК" gas supply valve or valve is replaced;
• - "B" shoe was repaired;
• - "O", a cylinder inspection is required;
• - "K" the ring was repaired;
• - "G" the neck was repaired;
• - "Y" gas leak in the connection;
• - "OKR" color of the cylinder;
• - "D" cylinder degassing;
• - "P" fistulas, undercuts, pores on the body.

Cylinders are accepted with documents indicating:

• the number of accepted cylinders;
• date of acceptance;
• number and volume of the container.

Inspect the cylinder carefully before replacing it. Cylinders are not accepted for exchange if:

• defects in damage to metal thickness over 10%;
• self-painted cylinders or cylinders in which the paint is damaged more than 30%;
• cylinders with damaged gas regulation and stabilization mechanisms are not exchanged;
• lack of a passport in the form of a metal plate on which all actions with the cylinder are indicated.

When receiving a new cylinder in return, inspect it and make sure it is intact. Check the operability of mechanisms, defects on the case and completeness.

The gas valve is an integral part of any gas equipment. In fact, it is a valve that supplies gas from a cylinder to a device that consumes it. Without a valve, the operation of the cylinder becomes impossible. At the same time, the repair of the gas cylinder valve is extremely rare, since this part is inexpensive and widely available. In addition, the use of damaged parts on gas equipment directly contradicts safety regulations. In this sense, replacing a damaged part is much more reliable. Since valves are of varying quality on the market, failure of this part is quite common.If you find any malfunctions in the work, you should contact a qualified technician or request a warranty repair. Replacing and repairing gas cylinder valves should in no case be carried out at home, it is extremely dangerous. Firstly, replacement of gas equipment parts is carried out exclusively on empty cylinders. Secondly, for the high-quality performance of such work, a specific tool is needed.

To avoid complex and costly repairs, you should handle gas cylinders with extreme care, in accordance with the requirements of the operating instructions, since most of the malfunctions are caused by shocks, falls, mechanical damage. Having found one of the described malfunctions and deciding on further actions with respect to the damaged cylinder, it should be remembered that the repair of the gas cylinder must be carried out by a qualified technician in a specially equipped place in compliance with all safety measures.

Cylinders are versatile equipment for storing and transporting gaseous substances for domestic and industrial purposes.

The shut-off valves in them are not eternal, therefore, over time, the valve on the gas cylinder needs to be replaced, which can be done independently in compliance with a number of safety rules.

Requirements for production processes and technical characteristics of gas cylinders are regulated by rather old GOST 949-73 and 15860-84.

The maximum working pressure in the devices ranges from 1.6 MPa to 19.6 MPa, and the wall thickness can vary from 1.5 to 8.9 mm.

A standard gas cylinder assembly consists of the following items:

1. Cylinder body.
2. Valve with shut-off valves.
3. Valve closing cap.
4. Washers for securing and transporting.
5. Support shoe.

The technical information embossed on it is also an important element of the cylinder.

The bottom of the cylinders is hemispherical for even distribution of internal pressure. For better stability of the body, a shoe is welded on the outside, on the lower edges of which there are often holes for attaching the cylinder to horizontal surfaces.

The threads on the valves for gas cylinders are standardized, but they themselves can have a variety of designs. The choice of the valve model is influenced by the type of stored chemical, the production characteristics of the operation and the amount of money. Before purchasing new equipment, you should familiarize yourself with the options and the internal arrangement of the valves.

The design features of gas cylinder valves are not due to the whims of engineers, but safety considerations.

Depending on the material of execution, shut-off valves are divided into:

The choice of metal for the manufacture of the valve body is due to the type of gases contained in the cylinder. A distinction is made between the following types of shut-off valves, depending on the type of stored chemicals:

1. Acetylene. The body of such cylinders is painted white. Special valves are used in cylinders with acetylene, chlorine, ammonia and other aggressive substances.
2. Oxygen... The cylinders are colored blue and are designed to store oxygen, argon, hydrogen, nitrogen, carbon dioxide and other inert gases.
3. Propane-butane... They are colored red and are intended to store the substances corresponding to the name and other gaseous hydrocarbons. The most common valve type model for such a cylinder is VB-2.

Valves for acetylene cylinders are not made of brass because the substances they contain can react chemically with copper. Usually, for the manufacture of valves of this type, carbon or alloy steel is used.

A standard gas valve has the form of a tee, each of which has an external thread.More advanced models may have an additional protrusion - a safety valve. Its purpose is to relieve excess pressure in case of heating of a full cylinder or in case of improper filling.

The lower union of the valve is used to connect to the gas cylinder, the upper one is used to attach the flywheel, and the side one is used to connect the communications for the gas outlet and injection. The device for a gas cylinder valve is quite simple. Shut-off valves usually consist of the following common elements:

1. Brass or steel body.
2. A stuffing box valve or a handwheel connected to the body with a union nut.
3. Internal locking mechanism with valve and stem.
4. Sealing gaskets.
5. Vent plug.

You can take a closer look at the device of valves on gas cylinders of each type in the presented images.

Worn out valves can allow a small amount of gas to pass through, which in closed rooms can lead to unpredictable consequences. To prevent such situations, a plug on the side fitting is used, which serves for additional sealing of the cylinder during transportation and long-term storage.

The direction of the threads on the outlets depends on the chemicals contained in the cylinders: the right one is used for non-combustible gases (oxygen, nitrogen, argon, etc.), and the left one is used for combustible gases (hydrogen, acetylene, propane, etc.)

The principle of the assembled gas valve is unremarkable. To supply gas and close it off, simply turn the flywheel slowly in the appropriate direction.

Precautions must be taken before replacing the gas cylinder valve. Work must be carried out in such a way as to protect a person from potential hazards and to keep the equipment in working order.

The following precautions are taken in the preparatory work for replacing the gas valve:

1. It is possible to release the remains of the contents of the cylinder only in an open space. An exception can be made only for nitrogen, air and argon.
2. The work area should be well ventilated, although it is advisable to work outdoors.
3. There should be only one closed gas cylinder within the workplace.
4. It is necessary to unscrew the flywheel slowly in order to prevent its electrification.
5. The valve can be replaced only after the final pressure equalization in the cylinder and outside.

When screwing the valve into the cylinder, fum tape or special lubricants are used, which provide increased tightness and strength of the connection. When replacing a valve, such seals greatly complicate the process of dismantling it. To solve this problem, you can warm up the valve with a hairdryer.

It is possible to heat the shut-off valves only after bleeding the gas from the cylinder and closing the valve. In this case, the procedure is safe and will not lead to unpredictable situations.

An alternative to a hair dryer can be wrapping the valve with a cloth and then pouring boiling water over it. With this heating method, any suitable plug must be screwed onto the outlet fitting to prevent water from entering.

After taking all the precautions and warming up the shut-off valves, you can start unscrewing the valve, which can be a difficult task at home.

An additional margin of tightness is not superfluous, but when replacing valves on a gas cylinder, the strength of its fastening can become a big problem. The difficulty lies in fixing the cylinder body in such a way that it does not rotate when the valve is unscrewed with a key. It is with this problem in mind that further step-by-step actions to replace the shut-off valves will be considered.

There are many ways to fix the body of a gas cylinder, we will consider some of them.

You will need the following tools and materials: a pipe wrench, two bolts from 20 mm long with two nuts and a metal corner profile at least a meter long. Instead of a corner, you can use any other product in which it is not a pity to drill two small holes.

Next, you need to measure the distance between the two nearest holes on the cylinder shoe and drill the corresponding holes from one edge of the metal profile. After that, screw the iron bar to the cylinder body with the bolts and put it on its side. This design will prevent the balloon from spinning.

Then you need to put your foot on a metal profile, and with your hand, using a key, carefully unscrew the valve.

A step-by-step photo instruction of the process is presented below.

This method is quite dangerous and should only be used by a professional welder with the utmost care. The shoe is gripped in two places so that after unscrewing the valve, the cylinder can be easily ripped off the base.

After the body is welded on, the fittings are carefully unscrewed with a pipe wrench. Then the inner thread of the cylinder should be cleaned from the remnants of the seal.

The methods of fixing the gas cylinder are not limited to the described options. Many alternative methods can be used to secure it.

At the bottom of the cylinder, liquid water condensate sometimes accumulates, therefore, after removing the valve, it is imperative to turn the container over so that water can flow out of it.

Before tightening the valve, all connected parts must be degreased to prevent clogging of the locking mechanism. To do this, you can use a rag with regular detergent or moistened with white alcohol. After that, the surfaces should be rinsed with plain water and allowed to dry.

The new valve is never bare threaded to the cylinder. It is imperative to use a sealant: a special thread compound or fluoroplastic fum tape. They are applied to the lower fitting and only after that the valve is tightened.

The thickness of the gas fum tape is greater than the sanitary one and is 0.1 - 0.25 mm, and its reel should be yellow. The tape is wound with a tension of 3-4 layers. It is better to twist it once more when it breaks than to make the seal loose.

It is desirable to tighten the valve with a torque wrench. Steel shut-off valves are screwed on with a maximum force of 480 Nm, and brass ones - 250 Nm. After clamping the valve, you can proceed to the subsequent steps to test the tightness of the resulting connection.

When checking the tightness of the valve connection, you will need to pump gas under pressure into the gas cylinder. This can be done in two ways:

1. Pump in gas using compressor equipment or an automobile pump.
2. Connect with a hose two cylinders, the first of which is empty (tested), and the second is filled with gas.

First, it is necessary, under the control of a manometer, to fill the test cylinder with a gas with a pressure of 1.5-2 atmospheres. After that, soap foam is applied to the connection and the tap is slightly opened. If soap bubbles are not inflated anywhere, then the connection is sealed. But if even slight swelling of foam appears, then you will have to twist the valve again.

If the bottle is small, then you can immerse its valve in a small bowl of water and see if there are any bubbles.

After replacing the shut-off valves, a corresponding mark must be made in the passport of gas cylinders.

The presented videos allow you to see with your own eyes all the details and difficulties when replacing a valve on gas cylinders.

Unscrewing the valve from the gas cylinder: