Selection-and-installation-of-safety-valve.pdf
This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA
Overview
Download & View Selection-and-installation-of-safety-valve.pdf as PDF for free.
More details
- Words: 2,463
- Pages: 9
www.steeljrv.com
[email protected]
Selection and installation of safety valve https://www.steeljrv.com/selection-and-installation-of-safety-valve.html 2019-04-04
Industry News
News
What is a safety valve? The safety valve used in pressure equipment, container or pipeline, as the overpressure protection device. When the equipment, container or piping within the pressure exceeds the allowable value, the valve automatically opens, then the whole amount of emissions, to prevent the equipment, container or piping within the pressure continues to rise; when the pressure is reduced to the specified value, the valve should be closed automatically in a timely manner, so as to protect the safe operation of equipment, container or piping.
Nominal terms
Classification of safety valves
Selection of safety valve How to order safety valve System safety valve by valve inlet pressure of the direct drive, in this case is the mechanical load provided by springs or weights to overcome the effect of the bottom of the medium pressure valve. They can also be driven by a body to guide, open or closed by applying a closing force to the valve through the release of the agency or. Therefore, in www.steeljrv.com
[email protected]
www.steeljrv.com
[email protected]
accordance with the drive mode will be divided into direct acting valve and pilot. Safety valve opening height in the entire range or in the open within the opening height ratio is quite large, also may open only a tiny proportion of the height range open, then suddenly open to the fully open position. Therefore, can be divided into the proportional valve and the full opening. To determine the structure, application and public safety valve should be subject to regulations, or should be a statutory authority to agree. Between different specifications, terms of its constraints and the definition may be different. In the application of safety valve, must follow the applicable specifications. The safety valve is an automatic valve, in the structure and performance parameters and the valves have many differences. Some special terminology easy to confuse, in order to enable users to more clearly understand the safety valve, and correctly use the following terminology to explain some of the main.
Safety valve nominal terms:
(1) Safety valve: an automatic valve. It does not use any external force, but the use of medium fertility to a nominal amount of fluid discharged to prevent the system pressure exceeds a predetermined safety value; when the pressure returned to normal, the valve closed again, and prevent the media continue to run.
(2) Direct loading type safety valve. A mechanical load by the direct effect of the safety valve, such as hammer, lever and weight or spring to overcome the medium pressure valve produced by force.
(3) Assisted safety valve. The safety valve with a power assist device, can open the pressure below the normal open. Even if the auxiliary device failure, the safety valve can still meet the requirements of standard.
(4) With added load safety valve. This safety valve in the inlet pressure to remain open before the pressure of a sealed pressure increase. The additional force (supplementary load) provided by the external energy, and opening pressure should be achieved reliably release in safety valve. Its size should be set so that the additional force is not released, still in the inlet pressure relief valve opening pressure does not exceed the provisions of state laws and regulations under the premise of the percentage of rated displacement.
(5) The pilot type safety valve. A safety valve on the media discharged from the pilot valve to drive or control. The pilot valve itself should be directly in line with requirements of the standard load safety valve.
www.steeljrv.com
[email protected]
www.steeljrv.com
[email protected]
(6) The proportion of type safety valve. An opening height in the entire range or in the open safety valve to open or close the height range of the considerable proportion.
(7) Safety valve. Only in a small proportion of open range of opening height, then suddenly open the valve to the full open position. The opening height of not less than 1/4 channel diameter.
(8) Micro open type safety valve. Is a direct effect only for liquid medium type safety valve. The opening height in 1/40 ~ 1/20 channel diameter range.
(9) Opening pressure (nominal pressure). Safety valve began to rise in the operating conditions of the inlet pressure, the pressure began to measure the opening height, the media was by visual or auditory continuous emission state of the heavenly stems and earthly branches.
(10) The discharge pressure. Open the valve to reach the required height of the inlet pressure. The maximum discharge pressure required to follow the relevant national standards or specifications.
(11) Over pressure. Discharge pressure and opening pressure difference, usually expressed as a percentage of opening pressure.
(12) The back seat pressure. After the discharge valve with the valve seat again, that turned into a zero height of inlet pressure.
(13) The opening and closing pressure. The opening pressure and back seat pressure difference, the percentage usually back seat pressure and opening pressure, only when used on low pressure the pressure difference said.
(14) The back pressure. Safety valve outlet pressure.
(15) Rated discharge pressure. Standard discharge pressure limit.
(16) Seal test pressure. To seal the inlet pressure test, measured by the pressure off parts of the sealing surface of the leakage rate.
(17) Leave the valve closed position of the actual lift.
(18) The flow area. The valve inlet to the minimum cross-sectional area close to the sealing surface between the channel, without any resistance displacement theory is used to calculate the influence of.
(19) The channel diameter. For the diameter of flow area.
(20) Curtain area. When the valve flap in the seat above, in the sealing surface formed between the cylindrical or cone-shaped channel surface area.
(21) Emission area. The minimum cross-sectional area of the valve when the fluid discharge channel. The Enlightenment of the safety valve, the discharge area equal to the flow area; the micro open type safety valve, the discharge area equal to the area of the curtain.
www.steeljrv.com
[email protected]
www.steeljrv.com
[email protected]
(22) The theory of displacement. Is to calculate the displacement of the flow cross-sectional area and valve flow area equal to the ideal nozzle.
(23) Displacement coefficient. The ratio of the actual displacement and theoretical displacement.
(24) The discharge coefficient and reduction coefficient (0.9) of the product.
(25) Rated capacity. Refers to the actual displacement is allowed as part of the safety valve for reference.
(26) The applicable conditions of pressure, temperature, dielectric properties and other conditions of displacement and rated the same, the calculation of valve displacement.
(27) Safety valve abnormalities rapidly back and forth movement, the movement of the valve seat contact.
(28) Safety valve abnormalities rapidly back and forth movement, the movement does not touch the valve seat.
Classification of safety valves Classification
Types of
Description
Direct acting
Directly relying on the force generated by the medium pressure to overcome the mechanical load acting on the valve flap to open the valve.
Pilot
According to the principle of action Indirect action
It consists of a main valve and a pilot valve. The main valve is driven or controlled by the medium discharged from the pilot valve
An additional force to enhance the seal is With maintained until the inlet pressure reaches supplementary the opening pressure. This additional force load should be reliably released when the valve reaches the opening pressure
Proportional action
The opening height changes gradually as the pressure increases
The opening process is divided into two According to the stages: at first the valve flap opens action proportionally with the increase of pressure. Both ends acting (bounce characteristics After the pressure rises to a small value, the action) valve flap is rapidly opened to the specified height when the pressure is almost no longer increased. Press
to
open Micro-open
www.steeljrv.com
[email protected]
The opening height is in the range of
www.steeljrv.com
height
1/40~1/20 channel diameter Fully open
Opening height is greater than or equal to 1/4 of the diameter of the runner
Zhongqi
Opening height between micro-open and full-open
Press with or Back pressure balance without back pressure balance mechanism Conventional
Press loading
[email protected]
Balance the back pressure with a bellows, piston or diaphragm to balance the action of the back pressure on the upper and lower sides of the valve Without back components
pressure
balancing
Heavy hammer or lever Load directly with a heavy hammer or load with a heavy hammer valve weight Spring type
Spring loaded
Air chamber
Load with compressed air
Selection of safety valve Applicable conditions
Safety valve type
Liquid medium
Proportional active safety valve
Gas medium, the necessary emissions Fully open safety valve are large When the displacement is large, use several safety valves at both ends, the total displacement The required displacement is variable is equal to the maximum required displacement. When the required displacement is small, the proportional action safety valve is used. The additional back pressure is atmospheric pressure, a fixed value, or Conventional safety valve a large amount of change (relative to the opening pressure) The additional back pressure is variable and the amount of change is Back pressure balanced safety valve large (relative to the opening pressure) Require quick response
Direct acting safety valve
The required displacement is large, or the caliber and pressure are large, and Pilot operated safety valve the sealing requirements are high. High sealing requirements, opening pressure and working pressure are Safety valve with supplementary load very close Mobile or equipment
vibrated
pressurized
www.steeljrv.com
[email protected]
Spring-loaded safety valve
www.steeljrv.com
[email protected]
Do not allow media to spill into the surrounding environment, or need to Closed safety valve recover the displacement of the media The medium can be released to the surrounding environment and the Open safety valve medium temperature is high High medium temperature
Safety valve with heat sink
The selection of the safety valve is closely related to the system being protected. The selected safety valve should be able to discharge the overpressure medium in the protected system within the specified time to ensure that the pressure in the system is lower than the design pressure of the system. Therefore, the reliability of the safety valve is directly related to the safe and economic operation and personal safety of the protected system. First, the principle of safety valve setting. The basic principle of the safety valve setting is for clean, particle-free, low viscosity fluids. When a safety valve must be provided where there are particles, it should be considered to add a filter before the safety valve, provided that the performance of the safety valve is not affected. Second, the pressure system of one of the following conditions must be installed with a safety valve. 1. The pressure material of the container is from the occasion without safety valve. 2. Containers and pipes designed to have a pressure less than the pressure source 3. The outlet pipe of the volume pump and compressor 4. If there is a shut-off valve and a control valve on the outlet pipe of the heating furnace, a safety valve should be installed at the front end. 5. The part of the liquid that is thermally expanded due to the closing of the valve at both ends 6. Other overpressure parts Third, the following occasions are not suitable for configuring safety valves 1. System pressure may rise rapidly, such as chemical explosions. 2. The diarrhea medium contains particles, easy to precipitate, easy to crystallize, easy to polymerize and medium viscosity 3. The diarrhea medium is highly corrosive, and the price is too high when using a safety valve 4. The working pressure is very low or very high, at this time the safety valve is more difficult to manufacture www.steeljrv.com
[email protected]
www.steeljrv.com
[email protected]
5. Need a larger area of diarrhea 6. The system temperature is low and affects the safety valve operating performance Fourth, the safety valve and rupture disc should be used in combination in the following cases. 1. The medium is very expensive or highly toxic, and there is no leakage in the middle of the work process. 2. Increase the discharge area under abnormal conditions (such as fire)
How to order safety valve? When the user chooses the safety valve, he should first calculate according to the actual working condition, determine the specific model, and order according to the need. When placing an order, at least the following items should be indicated on the order:
A. Type of safety valve, nominal diameter, runner diameter, connection form of inlet and outlet, pressure level;
B. Operation pressure and setting pressure of safety valve;
C. Material of safety valve (material of valve body, inner parts, spring, etc
D. Standards for manufacturing and acceptance of safety valves.
(2) Special requirements:
A. Maximum allowable excess pressure;
B. Necessary displacement and number of valves to be installed;
C. Physical properties of the medium, the name of the medium used, its weight or molar mass, and component ratio;
D. Medium working temperature, discharge temperature, etc.
E. Back pressure of relief valve;
F. Closed type, wrench, etc.
Source: China Safety Valves Manufacturer – Yaang Pipe Industry Co., Limited (www.steeljrv.com) (Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in
www.steeljrv.com
[email protected]
www.steeljrv.com
[email protected]
Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.) If you want to have more information about the article or you want to share your opinion with us, contact us at [email protected] Please notice that you might be interested in the other technical articles we’ve published:
Sealing Tests for Valves
What are valves
Nine Anti-Corrosion Measures of Valves
The Selection of Control Valve
Operation and Maintenance Manuals for Gate Valves
When the control valves are used in liquid service
Choosing Valves Based on Industry Characteristics
Designs and Uses of Ball Valves for Submarine Pipelines
What is a ball valve
How to choose valves
Cause Analysis of Valve Leakage
Summary
Article Name Selection and installation of safety valve Description The selection of the safety valve is closely related to the system being protected. The selected safety valve should be able to discharge the overpressure medium in the protected system within the specified time to ensure that the pressure in the system is lower than the design pressure of the system. Author https://www.steeljrv.com Publisher Name www.steeljrv.com Publisher Logo
www.steeljrv.com
[email protected]
www.steeljrv.com
www.steeljrv.com
[email protected]
[email protected]
[email protected]
Selection and installation of safety valve https://www.steeljrv.com/selection-and-installation-of-safety-valve.html 2019-04-04
Industry News
News
What is a safety valve? The safety valve used in pressure equipment, container or pipeline, as the overpressure protection device. When the equipment, container or piping within the pressure exceeds the allowable value, the valve automatically opens, then the whole amount of emissions, to prevent the equipment, container or piping within the pressure continues to rise; when the pressure is reduced to the specified value, the valve should be closed automatically in a timely manner, so as to protect the safe operation of equipment, container or piping.
Nominal terms
Classification of safety valves
Selection of safety valve How to order safety valve System safety valve by valve inlet pressure of the direct drive, in this case is the mechanical load provided by springs or weights to overcome the effect of the bottom of the medium pressure valve. They can also be driven by a body to guide, open or closed by applying a closing force to the valve through the release of the agency or. Therefore, in www.steeljrv.com
[email protected]
www.steeljrv.com
[email protected]
accordance with the drive mode will be divided into direct acting valve and pilot. Safety valve opening height in the entire range or in the open within the opening height ratio is quite large, also may open only a tiny proportion of the height range open, then suddenly open to the fully open position. Therefore, can be divided into the proportional valve and the full opening. To determine the structure, application and public safety valve should be subject to regulations, or should be a statutory authority to agree. Between different specifications, terms of its constraints and the definition may be different. In the application of safety valve, must follow the applicable specifications. The safety valve is an automatic valve, in the structure and performance parameters and the valves have many differences. Some special terminology easy to confuse, in order to enable users to more clearly understand the safety valve, and correctly use the following terminology to explain some of the main.
Safety valve nominal terms:
(1) Safety valve: an automatic valve. It does not use any external force, but the use of medium fertility to a nominal amount of fluid discharged to prevent the system pressure exceeds a predetermined safety value; when the pressure returned to normal, the valve closed again, and prevent the media continue to run.
(2) Direct loading type safety valve. A mechanical load by the direct effect of the safety valve, such as hammer, lever and weight or spring to overcome the medium pressure valve produced by force.
(3) Assisted safety valve. The safety valve with a power assist device, can open the pressure below the normal open. Even if the auxiliary device failure, the safety valve can still meet the requirements of standard.
(4) With added load safety valve. This safety valve in the inlet pressure to remain open before the pressure of a sealed pressure increase. The additional force (supplementary load) provided by the external energy, and opening pressure should be achieved reliably release in safety valve. Its size should be set so that the additional force is not released, still in the inlet pressure relief valve opening pressure does not exceed the provisions of state laws and regulations under the premise of the percentage of rated displacement.
(5) The pilot type safety valve. A safety valve on the media discharged from the pilot valve to drive or control. The pilot valve itself should be directly in line with requirements of the standard load safety valve.
www.steeljrv.com
[email protected]
www.steeljrv.com
[email protected]
(6) The proportion of type safety valve. An opening height in the entire range or in the open safety valve to open or close the height range of the considerable proportion.
(7) Safety valve. Only in a small proportion of open range of opening height, then suddenly open the valve to the full open position. The opening height of not less than 1/4 channel diameter.
(8) Micro open type safety valve. Is a direct effect only for liquid medium type safety valve. The opening height in 1/40 ~ 1/20 channel diameter range.
(9) Opening pressure (nominal pressure). Safety valve began to rise in the operating conditions of the inlet pressure, the pressure began to measure the opening height, the media was by visual or auditory continuous emission state of the heavenly stems and earthly branches.
(10) The discharge pressure. Open the valve to reach the required height of the inlet pressure. The maximum discharge pressure required to follow the relevant national standards or specifications.
(11) Over pressure. Discharge pressure and opening pressure difference, usually expressed as a percentage of opening pressure.
(12) The back seat pressure. After the discharge valve with the valve seat again, that turned into a zero height of inlet pressure.
(13) The opening and closing pressure. The opening pressure and back seat pressure difference, the percentage usually back seat pressure and opening pressure, only when used on low pressure the pressure difference said.
(14) The back pressure. Safety valve outlet pressure.
(15) Rated discharge pressure. Standard discharge pressure limit.
(16) Seal test pressure. To seal the inlet pressure test, measured by the pressure off parts of the sealing surface of the leakage rate.
(17) Leave the valve closed position of the actual lift.
(18) The flow area. The valve inlet to the minimum cross-sectional area close to the sealing surface between the channel, without any resistance displacement theory is used to calculate the influence of.
(19) The channel diameter. For the diameter of flow area.
(20) Curtain area. When the valve flap in the seat above, in the sealing surface formed between the cylindrical or cone-shaped channel surface area.
(21) Emission area. The minimum cross-sectional area of the valve when the fluid discharge channel. The Enlightenment of the safety valve, the discharge area equal to the flow area; the micro open type safety valve, the discharge area equal to the area of the curtain.
www.steeljrv.com
[email protected]
www.steeljrv.com
[email protected]
(22) The theory of displacement. Is to calculate the displacement of the flow cross-sectional area and valve flow area equal to the ideal nozzle.
(23) Displacement coefficient. The ratio of the actual displacement and theoretical displacement.
(24) The discharge coefficient and reduction coefficient (0.9) of the product.
(25) Rated capacity. Refers to the actual displacement is allowed as part of the safety valve for reference.
(26) The applicable conditions of pressure, temperature, dielectric properties and other conditions of displacement and rated the same, the calculation of valve displacement.
(27) Safety valve abnormalities rapidly back and forth movement, the movement of the valve seat contact.
(28) Safety valve abnormalities rapidly back and forth movement, the movement does not touch the valve seat.
Classification of safety valves Classification
Types of
Description
Direct acting
Directly relying on the force generated by the medium pressure to overcome the mechanical load acting on the valve flap to open the valve.
Pilot
According to the principle of action Indirect action
It consists of a main valve and a pilot valve. The main valve is driven or controlled by the medium discharged from the pilot valve
An additional force to enhance the seal is With maintained until the inlet pressure reaches supplementary the opening pressure. This additional force load should be reliably released when the valve reaches the opening pressure
Proportional action
The opening height changes gradually as the pressure increases
The opening process is divided into two According to the stages: at first the valve flap opens action proportionally with the increase of pressure. Both ends acting (bounce characteristics After the pressure rises to a small value, the action) valve flap is rapidly opened to the specified height when the pressure is almost no longer increased. Press
to
open Micro-open
www.steeljrv.com
[email protected]
The opening height is in the range of
www.steeljrv.com
height
1/40~1/20 channel diameter Fully open
Opening height is greater than or equal to 1/4 of the diameter of the runner
Zhongqi
Opening height between micro-open and full-open
Press with or Back pressure balance without back pressure balance mechanism Conventional
Press loading
[email protected]
Balance the back pressure with a bellows, piston or diaphragm to balance the action of the back pressure on the upper and lower sides of the valve Without back components
pressure
balancing
Heavy hammer or lever Load directly with a heavy hammer or load with a heavy hammer valve weight Spring type
Spring loaded
Air chamber
Load with compressed air
Selection of safety valve Applicable conditions
Safety valve type
Liquid medium
Proportional active safety valve
Gas medium, the necessary emissions Fully open safety valve are large When the displacement is large, use several safety valves at both ends, the total displacement The required displacement is variable is equal to the maximum required displacement. When the required displacement is small, the proportional action safety valve is used. The additional back pressure is atmospheric pressure, a fixed value, or Conventional safety valve a large amount of change (relative to the opening pressure) The additional back pressure is variable and the amount of change is Back pressure balanced safety valve large (relative to the opening pressure) Require quick response
Direct acting safety valve
The required displacement is large, or the caliber and pressure are large, and Pilot operated safety valve the sealing requirements are high. High sealing requirements, opening pressure and working pressure are Safety valve with supplementary load very close Mobile or equipment
vibrated
pressurized
www.steeljrv.com
[email protected]
Spring-loaded safety valve
www.steeljrv.com
[email protected]
Do not allow media to spill into the surrounding environment, or need to Closed safety valve recover the displacement of the media The medium can be released to the surrounding environment and the Open safety valve medium temperature is high High medium temperature
Safety valve with heat sink
The selection of the safety valve is closely related to the system being protected. The selected safety valve should be able to discharge the overpressure medium in the protected system within the specified time to ensure that the pressure in the system is lower than the design pressure of the system. Therefore, the reliability of the safety valve is directly related to the safe and economic operation and personal safety of the protected system. First, the principle of safety valve setting. The basic principle of the safety valve setting is for clean, particle-free, low viscosity fluids. When a safety valve must be provided where there are particles, it should be considered to add a filter before the safety valve, provided that the performance of the safety valve is not affected. Second, the pressure system of one of the following conditions must be installed with a safety valve. 1. The pressure material of the container is from the occasion without safety valve. 2. Containers and pipes designed to have a pressure less than the pressure source 3. The outlet pipe of the volume pump and compressor 4. If there is a shut-off valve and a control valve on the outlet pipe of the heating furnace, a safety valve should be installed at the front end. 5. The part of the liquid that is thermally expanded due to the closing of the valve at both ends 6. Other overpressure parts Third, the following occasions are not suitable for configuring safety valves 1. System pressure may rise rapidly, such as chemical explosions. 2. The diarrhea medium contains particles, easy to precipitate, easy to crystallize, easy to polymerize and medium viscosity 3. The diarrhea medium is highly corrosive, and the price is too high when using a safety valve 4. The working pressure is very low or very high, at this time the safety valve is more difficult to manufacture www.steeljrv.com
[email protected]
www.steeljrv.com
[email protected]
5. Need a larger area of diarrhea 6. The system temperature is low and affects the safety valve operating performance Fourth, the safety valve and rupture disc should be used in combination in the following cases. 1. The medium is very expensive or highly toxic, and there is no leakage in the middle of the work process. 2. Increase the discharge area under abnormal conditions (such as fire)
How to order safety valve? When the user chooses the safety valve, he should first calculate according to the actual working condition, determine the specific model, and order according to the need. When placing an order, at least the following items should be indicated on the order:
A. Type of safety valve, nominal diameter, runner diameter, connection form of inlet and outlet, pressure level;
B. Operation pressure and setting pressure of safety valve;
C. Material of safety valve (material of valve body, inner parts, spring, etc
D. Standards for manufacturing and acceptance of safety valves.
(2) Special requirements:
A. Maximum allowable excess pressure;
B. Necessary displacement and number of valves to be installed;
C. Physical properties of the medium, the name of the medium used, its weight or molar mass, and component ratio;
D. Medium working temperature, discharge temperature, etc.
E. Back pressure of relief valve;
F. Closed type, wrench, etc.
Source: China Safety Valves Manufacturer – Yaang Pipe Industry Co., Limited (www.steeljrv.com) (Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in
www.steeljrv.com
[email protected]
www.steeljrv.com
[email protected]
Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.) If you want to have more information about the article or you want to share your opinion with us, contact us at [email protected] Please notice that you might be interested in the other technical articles we’ve published:
Sealing Tests for Valves
What are valves
Nine Anti-Corrosion Measures of Valves
The Selection of Control Valve
Operation and Maintenance Manuals for Gate Valves
When the control valves are used in liquid service
Choosing Valves Based on Industry Characteristics
Designs and Uses of Ball Valves for Submarine Pipelines
What is a ball valve
How to choose valves
Cause Analysis of Valve Leakage
Summary
Article Name Selection and installation of safety valve Description The selection of the safety valve is closely related to the system being protected. The selected safety valve should be able to discharge the overpressure medium in the protected system within the specified time to ensure that the pressure in the system is lower than the design pressure of the system. Author https://www.steeljrv.com Publisher Name www.steeljrv.com Publisher Logo
www.steeljrv.com
[email protected]
www.steeljrv.com
www.steeljrv.com
[email protected]
[email protected]
More Documents from "Y Ya"
Selection-and-installation-of-safety-valve.pdf
October 2019 8
Draft Undangan Nut Mgt Kdm-untuk Dietition Rev(1).docx
August 2019 35
Virgo-and-hadluja-case.docx
June 2020 10
1.materi Pemanasan Global.docx
July 2020 13