PRESSURE-VACUUM RELIEF BREATHER VALVES
Description
Pressure-Vacuum Relief Breather Valve is a kind of air breathing which is installed on the petrochemical fixed storage tanks and/or vessels, in order to avoid tank over pressure or over vacuum that can destruct the storage tanks, prevent the outside flame enter, reduce the tank fluid volatile.
Pressure-Vacuum Relief Breather Valves provide protection to bulk storage tanks and vessels from over and under pressurization.
The valves are mounted on the tank roof flanges or vent pipes from the vapor space.
Principle of Operating
End of Line Pressure-Vacuum Relief Breather Valve can be configured with both weight-loaded or spring-loaded pallets refer to the specific required set pressure and vacuum. Flow through the valve is controlled by the weight of the pallet or the spring force acting on the pallet to keep the device closed when the pressure is below the set limit.
Once the pressure or vacuum in the tank reaches the pallet closing force, the pallet will start to lift off the seat and allow flow through the valve.
Due to its air-cushioned sealing technology, the breather valves prevent emission losses until very close to the set pressure, and prevent air intake until very close to the set vacuum.
The geometry of the valves has been developed in order to optimize overall performance in terms of high flow capacity, set pressure, sealing and re-sealing.
The modular nature of the breather valves means they can be tailored to meet specific customer requirements: Whether this is pressure or vacuum-protection only; or vapors and gases either piped-away or vented to atmosphere.
A weather-hood protects the pressure vent port and a mesh screen is fitted to prevent intrusion of foreign matters into the valve.
In the closed position, the pressure relief pallet and diaphragm assembly is held tightly against the seal to prevent the loss of vapor to atmosphere. As the internal pressure in the tank increases, due to product filling and vapor development, the pressure in tank increases and in the event that the set pressure of the unit is reached, the diaphragm will open and discharge the gas to atmosphere.
The vacuum pallet and diaphragm assembly is similarly maintained in the closed position. As the internal pressure in the tank reduces, due to emptying, the balance between the tank pressure and the external atmospheric pressure changes, and when the set pressure of the unit is reached, the diaphragm opens to admit air and rebalance the internal pressure.
The vacuum set-point is selectable from a range between +61 mbar and +1000 mbar (+622 mmWC and 10197 mmWC). The valve will reseal when the tank returns to a safe pressure.
Several features are inherent in the valve design to ensure a smooth, positive, and effective operation. The body is self-draining and drip rings prevent condensate from settling on seating surfaces. A diaphragm and seal manufactured from Teflon reduce the possibility of ice formation and sticky residues hindering the valve from opening, while the pallet assembly moves freely on guide posts. The outlet port is protected by a weather hood and mesh guard to prevent ingress of debris that might obstruct the opening, while a mesh filter screen in the vacuum inlet port performs the same function.
According to the code GB 50160 of Fire Prevention of Petrochemical that stipulate: ”A, B kind of fluid fixed arch-roof tank should set flame arrester and breathing valve” in order to meet the requirement, we develop and exploit all-weather (fire-proof) breathing valves whole series. Within scientific and smart mould, complete specification type, compact construction, light weight, huge breathing capacity, small leakage, and more features. The product construction have breathing type, single exhaust type, single suction type, reducing type, jacket type (detail information please refer HX series breathing valve). Every kind of series can mount flame arrester, suction, and exhaust connection nozzle.
They also can be manufactured in any different materials according to different mediums, such as petroleum, chemical, water of foods and beverages, totally satisfy every kinds of storage system process requirements.
Design, manufacture, and test according to the API 2000 code, these valves utilize the latest technologies to provide protection against positive or vacuum over pressure and prevent air intake, evaporative losses of product and help to contain odorous and potentially explosive vapors.
These pressure vacuum breather valves maintain a tight seal until system pressure or vacuum exceeds the set pressure.
The valves allow an intake of air under constant pressure during emptying, or discharge excessive over pressure during filling of the tanks.
High strength, one-body casting provide added structural integrity and durability.
Body materials are available in Aluminum, Carbon Steel, 304SS, and 316SS with various trims to suit specific requirements.
End of Line Pressure-Vacuum Relief Breather Valves have two different types, we name them SBB and SBS models, both they are advanced designed for vent to atmosphere applications.
1. Model SBB
The model SBB is a weight-loaded pallet type that designed to handle low pressure settings.
The vacuum set-point is selectable from a minimum pressure of +/-2.0 mbar (20 mmWC), and a maximum setting of +/-69 mbar (700 mmWC).
The models SBB and SBS End of Line Pressure-Vacuum Relief Breather Valves are advanced design for vent to atmosphere applications.
Designed manufactured and tested according to the API 2000 code, these valves utilize the latest technologies to provide protection against positive or vacuum over pressure and prevent air intake, evaporative losses of product and help to contain odorous and potentially explosive vapors.
These pressure vacuum valves maintain a tight seal until system pressure or vacuum exceeds the set pressure.
The valves allow an intake of air under constant pressure during emptying, or discharge excessive over pressure during filling of the tanks.
The KSBB is a weighted pallet model designed to handle pressure and vacuum with a minimum pressure of +/-20mmW.C and a maximum setting of +/- 700mmW.C
The KSBS is a spring loaded model designed to handle pressure and vacuum with a minimum pressure of +/-700mmW.C and a maximum setting of +/- 7,000mmW.C.
High strength, one-body casting provide added structural integrity and durability.
Body materials are available in Aluminum, Carbon Steel, 304SS and 316SS with various trims to suit individual requirements.
Sizes range from 50mm through to 300mm with ANSI 150lb FF flanges as standard. (Different connections available on request).
The valves have additional FM factory mutual approval for the majority of sizes and materials.
2. Model SBS
The model SBS is a spring-loaded pallet type that designed to handle high pressure settings.
The vacuum set-point is selectable from a minimum pressure of +/-69 mbar (700 mmWC), and a maximum setting of +/-686 mbar (7,000mmW.C).
Pressure Vacuum Relief Valve provides protection to bulk storage tanks and vessels from over and under pressurisation. The valves are mounted on the tank roof flange or a vent pipe from the vapour space.
In the closed position the pressure relief pallet and diaphragm assembly is held tightly against a seal to prevent the loss of vapour to atmosphere. As the internal pressure in the tank increases, due to product filling and vapour development, the pressure in tank increases and in the event that the set pressure of the unit is reached, the diaphragm will open and discharge the gas to atmosphere. The opening set-point is selectable from a range between +61 mbar and +1000 mbar (+24 inch W.C. and 400 inch W.C.), and the valve will reseal when the tank returns to a safe pressure.
The vacuum pallet and diaphragm assembly is similarly maintained in the closed position. As the internal pressure in the tank reduces, due to emptying, the balance between the tank pressure and the external atmospheric pressure changes, and when the set pressure of the unit is reached, the diaphragm opens to admit air and rebalance the internal pressure. The vacuum set-point is selectable from a range between +61 mbar and +1000 mbar (+24 inch W.C. and 400 inch W.C.). The valve will reseal when the tank returns to a safe pressure.
Several features are inherent in the valve design to ensure a smooth, positive and effective operation. The body is self-draining and drip rings prevent condensate from settling on seating surfaces. A diaphragm and seal manufactured from Teflon reduce the possibility of ice formation and sticky residues hindering the valve from opening, while the pallet assembly moves freely on guide posts. The outlet port is protected by a weather hood and mesh guard to prevent ingress of debris that might obstruct the opening, while a mesh filter screen in the vacuum inlet port performs the same function.
Application
The application can be for all working mediums such as gasoline, kerosene, diesel oil, aromatic naphtha, air, etc. or other petrochemical materials.
Standard of manufacture and inspection
Manufacture and inspection refer to the standard “SY/T0511.1-2010”.
Remark: Flange connection adopt HG/T20592-2010, PN1.0 MPa, and also available on request according to HG, JB, ANSI-B16.5, JIS.
Construction
The item’s body materials are available in Aluminum, Carbon Steel, 304 Stainless Steel, 316 Stainless Steel, and other metals on request.
As our standard, Carbon Steel material is supplied in Epoxy finish coated.
Standard sizes range from 2" (DN50) to 16" (DN400) with flange drilling according to ANSI #150 or API 650, FF flanges as standard, but different connections such as DIN, JIS standard, and other designs are available on request.
Explosion level: IIA, IIB, IIC
Operating pressure
A. -295 Pa (-30 mmH2O) +355 Pa (+36 mmH2O)
B. -295 Pa (-30 mmH2O) +980 Pa (+100 mmH2O)
C. -295 Pa (-30 mmH2O) +1750 Pa (+180 mmH2O)
D. Customer specified
Temperature
Ambient temperature : -4 ºF (-20 ºC) to 140 ºF (60 ºC)
Construction is designed for process temperature ranges : -4 ºF (-20 ºC) to 140 ºF (60 ºC)
Sizes
The Pressure-Vacuum Relief Breather Valves are available in the standard range of sizes from 2” (DN50) to 16” (DN400), and must be ordered with one of the optional model and specification.
The flange drillings according to ANSI #150 or API 650, FF flanges as standard, but different connections such as DIN, JIS standard, and other designs are available on request.
Remark: Flange connection adopt HG/T20592-2010, PN1.0 MPa, and also available on request according to HG, JB, ANSI-B16.5, JIS.
Features
These are some options available for our Breather Valves:
• The Pressure Vacuum Relief Breather Valves are available in a number of combinations mentioned below:
- Pressure and Vacuum Relief Valves
- Pressure Only Relief Valves
- Vacuum Only Relief Valves
• All breather valve combinations are available in a wide range of sizes, and can have flanged outlets or vent to atmosphere on both the pressure and vacuum, depend on user’s requirements.
• Flexibility: Available in wide range of sizes to suit diverse systems
Available in wide range of connection types to suit diverse standards
Available in wide range of materials to suit diverse applications
• Wide range of sizes and materials to suit diverse applications.
• Wide range of pressure settings to provide maximum tank protection whilst ensuring minimum product vapor.
• Low cost maintenance.
• Robust construction, built to withstand regular use in adverse conditions
• Superior quality
Ordering Information
Specify:
1. Model
2. Position of installation
3. Set vacuum and set pressure
4. Body material
5. Size
6. Type of connection flange
7. Flange standard based on ANSI, JIS, DIN, or API
8. Rating class of flange