Usage of liquefied gas valve main characteristics

2022-07-22
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Liquefied gas valve is a forced sealing valve, so when the valve is closed, pressure must be applied to the valve disc to force the sealing surface not to leak. When the medium enters valve VI from below the valve disc, the resistance to be overcome by the operating force is the friction between the valve rod and the packing and the thrust generated by the pressure of the medium. The force to close the valve is greater than the force to open the valve, so the diameter of the valve rod should be larger, otherwise the valve rod bending fault will occur

liquefied gas valve, also known as shut-off valve, is the most widely used valve. Its popularity is due to the small friction between sealing surfaces during opening and closing, relatively durable, low opening height, easy manufacture and maintenance. It is not only suitable for medium and low pressure, but also suitable for high pressure. The following editor will introduce the use methods of liquefied gas valves and the main characteristics of liquefied gas

installation of liquefied gas valve

1. Clean the inner cavity of liquefied gas valve before installation, and remove the defects caused in transportation

2. The installation of liquefied gas valve should keep the transmission shaft of butterfly valve horizontal and the piston valve vertical upward

3. Before using the liquefied gas valve, the transmission device should be debugged to keep all functions of the transmission device intact, and the limit stroke and over torque protection and control are reliable

4. Fully add lubricating oil to all lubricating parts of liquefied gas valve transmission device before commissioning and use

5. Before starting the electric device, carefully read the manual of the electric device of the liquefied gas valve provided with the machine

how to use the liquefied gas valve

1. Before installing the valve, the special valve cavity must be cleaned, and the defects generated in the transportation process must be clear, so as to avoid the impact of these defects on the normal operation of the valve

2. Install the liquefied gas valve in a place easy to maintain and on a horizontal pipeline

3. When installing the liquefied gas valve, first open the channel pipe next to it to drain the condensate and other mixtures in the pig

4. The liquefied gas valve is a sealed valve, so when we close the valve, we must apply a certain pressure to the valve disc. The pressure is applied to force the sealing without leakage. When the gas enters the valve, the friction force between the valve rod and the gas and the thrust generated by the medium entering the valve are the resistance to be overcome when the gas enters, so the diameter of the valve should be large enough

main characteristics of liquefied gas

1, flammable and explosive. There is a greater risk of fire and explosion accidents than gasoline and other oils and natural gas. Liquefied gas reaches a certain concentration in the air. Even in cold areas, small sparks emitted when encountering static electricity or metal impact can quickly cause combustion. The mixture concentration of liquefied gas and air is 2-10%, which will cause an explosion

2. Large gas-liquid volume ratio and volatile: under normal temperature and pressure, liquid liquefied gas is rapidly vaporized into 250-350 times the volume of liquefied gas

3. The specific gravity of liquid is lighter than that of water. Like oil, it floats on the water surface, which is about half the proportion of water

4. The specific gravity of gas is heavier than that of air, which is about 1.5-2 times that of air. Therefore, LPG leakage is very easy to deposit in low-lying places, causing combustion and explosion accidents

5, the volume expansion coefficient is large. The volume expansion coefficient of liquefied petroleum gas is about 10 ~ 16 times that of water at the same temperature. With the increase of temperature, the liquid volume will continue to expand, and the gas pressure will also continue to increase. For every 1 ℃ increase in temperature, the volume expansion will be 0.3 ~ 0.4%, and the pressure will increase by 0.2 ~ 0.3MPa

6, low boiling point. Generally, the boiling point is below 0 ℃. In China, especially in the south, even under the coldest temperature in winter, it can be naturally gasified

7, low flash point. Below 28 ℃, the lowest combustion temperature for the formation of volatile mixed gases is called flash point. The combustion that is prone to flash point only shows instant flames or flashes, and flash point is the precursor of fire

8. Corrosivity: the corrosivity in liquefied gas is mainly a small amount of sulfide, which is slightly corrosive to steel equipment and has a melting effect on rubber

9. Odorability: liquefied petroleum gas has no special smell. In order to easily detect leakage, additives such as ethanethiol are added to liquefied petroleum gas for odorization

10. Toxicity and asphyxiation: LPG has low toxicity. When the concentration of LPG in the air exceeds 1%, people will vomit and feel headache; When it reaches 10%, people can be anesthetized in two minutes. When the human body inhales high concentration of liquefied petroleum gas, suffocation will occur

editor's summary: This is the introduction to the use of liquefied gas valves and the main characteristics of liquefied gas. I hope it will be helpful to you. If you want to know more about it, you can pay attention to the information

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