GB 12244-89 General Requirements for Pressure Reducing Valves
1 Scope
This standard specifies the general requirements for pressure reducing valves used in the control and regulation of pressure in the process of manufacturing, water supply, heating and other processes.
2 Normative References
This Standard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this Standard only when incorporated in it by amendment or revision. For undated references, the latest edition shall be applied.
GB/T 12209.1 Pressure Piping Pressure Test
GB/T 12210.1 Process Piping Installation Acceptance Test
GB/T 12210.2 General requirements for installation acceptance test
3 Terms and Definitions
3.1 Pressure reducing valve (PRV)
Valve used to automatically reduce a higher incoming pressure to a lower setpoint.
3.2 Pressure differentia
The difference between the upstream pressure and downstream pressure at the PRV.
3.3 Rated flow
The maximum flow rate through the angled valve.
3.4 Maximum pressure drop
The pressure differential between the upstream and downstream port of the PRV at the maximum pressure.
4 Design
4.1 Design Basis
4.1.1 The pressure reducing valve shall meet the relevant requirements specified in GB/T 12209.1 and GB/T 12210.1.
4.1.2 The valve shall at least provide the following characteristics:
a) Valve shall be cast iron and the body trim shall include a gate, globe, ball and other kind of valve, either directly operated or by chain wheel actuator;
b) Flow control from 10% to 100%;
c) Upstream Pressure range from 0.3MPa to 1.2MPa;
d) Downstream pressure range from 0.04MPa to 0.8MPa;
e) Rated flow of 2m³/h to 30m³/h and maximum pressure drop of 0.2MPa to 0.6MPa.
4.2 Valve Construction
4.2.1 The body material of the valve shall be cast iron alloy and shall be in accordance with the requirements of GB/T 12210.2.
4.2.2 The body shall have a seat, an internal passage and an external connection.
4.2.3 The seat shall be able to prevent leakage from the downstream side of the valve to the upstream side, even under maximum pressure.
4.2.4 The internal passage shall be formed to ensure adequate flow characteristics.
4.2.5 The external connections shall be threaded to match the process piping.
4.3 Proprietary Device
4.3.1 The valve shall be fitted with an appropriate proprietary device, such as a pressure gauge, pressure switch and/or flow indicator, as deemed necessary.
4.3.2 The enabling device shall be sized to match the operating pressure and flow rate of the valve.
4.3.3 The enabling device shall be designed and manufactured to withstand the specified operating and test pressures.
4.4 Accessories
The valve shall be provided with necessary accessories including, but not limited to, bolts, nuts, washer and gaskets.
5 Test
5.1 Test Process
The pressure reducing valve shall be subjected to the following tests:
a) A proof test or a hydrostatic test, at least at a pressure equal to the maximum operating pressure plus 50% or at 1.5 times the design pressure, whichever is higher;
b) Maximum flow test, at least at a flow rate equal to the maximum flow required by the design;
c) Maximum pressure drop test, at least at a pressure differential equal to the maximum pressure required by the design;
d) After the valve has undergone the above-mentioned tests, the rated flow shall be tested at least again to ensure proper operation.
5.2 Test Rating
The valve shall be tested and rated for the following properties:
a) Maximum allowable operating pressure;
b) Maximum allowable inlet pressure;
c) Rated flow;
d) Maximum pressure drop;
e) Flow characteristics at various settings.
5.3 Test Equipment
The tests shall be conducted using calibrated test or measuring instruments and equipment with an accuracy adequate to ensure the accuracy of the test results.
5.4 Test Valves
The test valves shall be installed on the upstream and downstream sides of the pressure reducing valve to control and regulate the pressure during the tests.
5.5 Recording
The test results shall be accurately recorded and stored on the manufacturer’s documentation system.
6 Packaging、Marking and Transportation
6.1 Packaging
The pressure reducing valve shall be properly packaged for transportation.
6.2 Marking
The pressure reducing valve shall be clearly and permanently marked. The marking shall include product model, pressure rating, temperature rating, and pressure range.
6.3 Transportation
The pressure reducing valve shall be handled and stored in accordance with the manufacturers instructions.
