During the operation of the compressor, many supporting accessories need to be well matched to meet the gas demand of the terminal, and the pressure vessel (gas tank) is one of the indispensable accessories. It can stabilize the pressure of the pipe network system, remove some pollutants, reduce the frequent startup and shutdown of the compressor, extend the service life of the compressor, and reduce energy consumption, which is an integral part of the air compressed air system. However, in recent years, we often hear about accidents and even explosions of gas tanks, which seriously affect production and cause great damage to people and property. Therefore, the state and patrol inspection of pressure vessels are particularly important.

The pressure vessel is mainly composed of three parts: air receiver, safety valve and pressure gauge. The safety valve and pressure gauge are mainly used to ensure the safety of the air tank. The pressure vessel (gas tank) is a closed steel tank. Many potential safety hazards occur due to high pressure inside, which can cause explosion and damage equipment and personal safety. There are also many accidents caused by improper use of air compressor pressure vessels.

Reasons for potential safety hazard of air tank

(1) Design/production defects

The air receiver was not designed according to relevant specifications. The equipment material, design pressure, design temperature, welding coefficient, strength test, nondestructive testing, connection and reinforcement of connecting pipe, selection and parameter determination of corrosion allowance, setting and design structure of overpressure relief device are unreasonable. There are defects such as uneven wall thickness, air holes, cracks, severe corrosion, etc. Even though the air receiver can still work under the rated pressure, there are still potential safety hazards.

(2) Overpressure

There are many reasons for overpressure of the gas tank, such as unreasonable type selection of the gas tank, the design pressure of the selected tank is lower than the discharge pressure of the compressor, the failure of the compressor safety relief device or pressure regulating device, and the failure of the matching safety valve on the gas tank. In addition, most of the gas storage tanks are connected to oil injection screw air compressors, and some metal particles, dust, rust, deteriorated emulsified oil and sludge will enter the gas storage tank through the pipeline along with the mixed flow of oil and gas. Because the air receiver has a buffer function, the speed of air flow will slow down when passing through the air receiver. Sometimes these pollutants cannot be completely discharged through the drain outlet, which is very easy to accumulate in the air receiver, causing system overpressure, and even causing fire and explosion due to static electricity and other reasons.

(3) Vibration

The vibration caused by the air compressor will be transmitted to the gas tank through the pipeline. If the gas tank is not installed in a standard way and no good measures are taken to eliminate the vibration, the pipeline vibration will be caused, the connection will be loose, and the pipeline will be cracked, which may cause compressed gas leakage or safety accidents.

Elimination of potential safety hazard of air tank

(1) Prevention of overpressure

In addition to the reasonable setting of reliable and effective safety relief device for the air tank body, the air compressor shall have effective protective measures to stop pressurizing when the system pressure reaches the rated value. The compressor body shall also be equipped with a qualified and effective safety relief device. If the pipeline system entering the air tank is equipped with a pressure regulating device, its reliability and overpressure protection device shall be ensured to jointly ensure that the system overpressure will not bring accident risk.

(2) Regular cleaning

The compressor needs to strictly control the amount of lubricating oil injected. If the compressor is found to have abnormally high oil consumption or a large amount of oil contamination is discharged, it needs to stop the compressor for inspection in time; It is strongly recommended to select the air tank with manhole, and regularly clean the pollutants attached to the inner wall.

(3) Strengthen management and maintenance

The equipment is in charge of seven parts and repaired three parts. For the gas receiver, the user needs to formulate a detailed workflow, strengthen daily inspection, operate and record in strict accordance with the regulations, and eliminate the failure in the bud.

Strengthen daily patrol inspection of pressure vessels

(1) Patrol inspection of air receiver

① Inspection date

The gas tank is a pressure vessel equipment filed by the labor department, and it is a separate project in the equipment account. How many are there in each factory? How big?

Capacity? How much pressure? When will it be inspected? The labor department has detailed records. Blue iron plate with number shall be hung on the air receiver

Record the quality inspection within a certain period.

As a user of the air compressor station, he/she shall regularly fill in the patrol inspection form of the air receiver. For the patrol inspection of the air receiver, the first item is the inspection date

The standard is within the inspection period, and the inspection method is visual inspection. Because there is a standing book, whether it is within the inspection period is naturally traceable.

② Enclosure integrity

The second patrol inspection item of the air receiver is the integrity of the shell. The inspection standard is no damage, oil stain or rust. Inspectors

The law is also visual. The outer paint of the air receiver will fade due to the wind, sun and rain, so it should be painted every few years.

③ Sealing condition

The third item of patrol inspection is to check the sealing condition. The standard is no leakage, and the inspection method is visual inspection. Of course, this way must only

It is the roughest inspection. If conditions permit, listen carefully for air leakage. Gas leak detection can also be used

The instrument can quickly detect whether there is air leakage.

④ Pressure

The fourth inspection item is pressure, to prevent overpressure of the air tank due to various unexpected reasons. The inspection method is to check the pressure gauge.

⑤ License plate

The fifth item is license plate inspection. The standard is to hang the license plate at a conspicuous position without damage or loss. The inspection method is visual inspection.

(2) Safety valve

The safety valve is the key to ensure the safe operation of the air receiver and compressor, so it is a part submitted for regular inspection

There are records, instrument numbers, account management, etc.

If the pressure of the air tank rises to the upper limit, the safety valve starts to discharge the gas in the tank for pressure relief. If the safety valve fails, an overload occurs

The pressure may lead to the leakage of the welding seam and the explosion of the tank body, leading to safety accidents, so the safety valve is very important.

During patrol inspection, the first thing is to check whether the inspection date is reached. There are standing books for the inspection of safety valves. If the inspection date is reached, it should be sent in time

Inspection. There shall be a qualified inspection label after the inspection. The second item is that the shell is complete without damage, oil stain or rust.

The third item is the sealing condition, no leakage and normal operation.

(3) Pressure gauge

The key observation object of the pressure vessel is the pointer reading of the pressure gauge, which is equivalent to the eyes of the pressure vessel, and the internal pressure

The change can be clearly seen from the pressure gauge reading, which is also the only window for us to understand the internal conditions of the air tank

In daily inspection, it is necessary to observe.

In the past, the pressure of the air tank can be displayed through the 24-hour recording line chart of the pressure gauge. So the daily pressure of the compressor

The force change can be displayed. If there is a fault, it can also be reflected by finding the time point of the fault through the chart, which is convenient for operation

Personnel shall analyze and find out the cause of failure. In general, when the compressor has pressure vessel failure, the pressure in the air tank is too high

It is caused by normal outlet pressure. If the pressure gauge fails to read the normal value, or the safety valve expires, or for various reasons

Failure will lead to excessive pressure and accidents.

During the patrol inspection, the first item of the pressure gauge is to look at the identification. The inspection standard is regular inspection, and the identification is not damaged. Second, check the pressure indication

Whether the value is within the normal range and changes with the stop and other action pointers.

The state pays special attention to pressure vessels, especially the manufacturers of pressure vessels, which are set as special industries by the state

Production is not allowed if the product safety and quality cannot be guaranteed with the permission of.

In our work, when the air compressor went to the relevant municipal departments to obtain the pressure vessel operation certificate, we classified the air compressor into the pressure vessel field

The examination of the operation certificate of the force vessel is passed by 90 points, and the biennial examination is very difficult and demanding. Pressure vessel operation certificate and ID card

Similar appearance, including chip, it is difficult to reissue if lost. As a device with high safety performance requirements, pressure vessel is required by the state

We can see the strictness of.