Explanation of Valve Performance and Other Terms

1. Main performance parameters: It indicates the main parameters of the valve, such as nominal pressure, nominal opening and closing, and working temperature.

2. Nominal pressure: It is a pressure-related marking code expressed by numbers, and it is a convenient round integer for reference.

3. Nominal diameter: It is a numerical dimension commonly used for all accessories in the pipeline system to distinguish those parts expressed by thread or outside diameter. The nominal diameter is a convenient round integer for reference, which is not strictly related to the machining size.

4. Working pressure: It refers to the pressure of the valve at the applicable medium temperature.

5. Operating temperature: It refers to the temperature of the valve in the applicable medium.

6. Applicable medium: It refers to the medium to which the valve can be applied.

7. Applicable temperature: It refers to the applicable medium and temperature range of the valve.

8. Shell test: It refers to the pressure test of the whole valve shell formed by the connection of the valve body and bonnet. The purpose is to test the compactness of the valve body and bonnet and the pressure resistance of the whole shell including the joint between the valve body and the bonnet.

9. Shell test pressure: It refers to the pressure specified during the shell test of the valve.

10. Sealing test: It refers to the test to check the sealing performance of the opening and closing parts and the valve body sealing pair.

11. Sealing test pressure: It is the specified pressure when the valve is sealed.

12. Upper sealing test: It refers to the test to check the sealing performance of the valve stem and bonnet sealing pair.

13. Leakage: It is for valve sealing test, within the prescribed duration by the sealing surface.

14. Fitness: The ratio of the radial minimum contact width of the matching sealing pair to the minimum sealing surface width of the sealing pair.

15. Classification of valves: It is according to their use or main structural characteristics.

16. Model: It refers to the valve model according to its type, transmission mode, connection form, structural characteristics, valve seat sealing surface material and nominal pressure.

17. Main dimensions: It refers to the opening and closing height of the valve, the diameter of the handwheel and the connecting dimensions, etc.

18. Size: It refers to the size of the pipe connection part of the connecting valve.

19. Set pressure: It refers to the predetermined pressure at which the pressure relief valve starts to open under operating conditions. Under this pressure, the force to open the valve flap is balanced with the force to keep the valve flap on the valve seat.

20. Excess pressure refers to the pressure increased by exceeding the setting pressure of the safety valve, usually expressed as a percentage of the set pressure.

21. Back-seat pressure refers to the static pressure value at the inlet when the disc contacts with the valve seat again, that is, the opening height becomes zero.

22. The opening and closing pressure difference: It refers that the difference between the set pressure of the relief valve and the return pressure, which is usually expressed as a percentage of the set pressure.

23. Cold test for differential pressure: The safety valve is adjusted on the test bench to the static pressure at the inlet at the beginning of opening, which includes the correction of operating conditions such as backpressure and temperature.

24. Discharge pressure: It refers to the set pressure plus excess pressure.

25. Discharge backpressure: It is the pressure formed at the outlet of the valve when the medium flows into the discharge system through the safety valve.

26. The additional back pressure: It refers to the static pressure existing at the outlet of the safety valve when the additional back pressure device is running, which is caused by other pressure sources in the discharge system.

27. The open height: It refers to the actual lift of the open height disc from the closed position.

28. Initial lift: It refers to the initial lift, which causes the first displacement indication to appear on the displacement transducer or similar instrument.

29. Flow area: It refers to the minimum cross-sectional area between the inlet end of the valve and the sealing surface of the valve seat (but not the "curtain" area), which is used to calculate the theoretical displacement without any resistance.

30. The diameter of the runner: It corresponds to the diameter of the runner area.

31. Curtain area: When the valve flap rises above the valve seat, the cylindrical or conical channel area forms between its sealing surfaces.

32. Theoretical displacement: It is the calculated displacement of the theoretical nozzle whose cross-sectional area is equal to that of the safety valve.

33. Displacement coefficient: It refers to the ratio of actual displacement to theoretical displacement.

34. Rated displacement coefficient: It refers to the product of displacement coefficient and reduction coefficient (take 0.9).

35. Rated displacement: It refers to the part of the actual displacement of the rated displacement that is allowed as the applicable reference of the safety valve, that is, the value calculated according to the following A, B, or C.

A. Actual displacement × reduction coefficient (0.9)
B. Theoretical displacement × displacement coefficient × reduction coefficient (0.9)
C. Theoretical displacement × rated displacement coefficient

36. Equivalent calculated displacement: It refers to the calculated displacement of the safety valve when the pressure, temperature or characteristics of fluid are different from those of industrial and mining with rated displacement.

37. Frequency jump: The disc of the safety valve moves back and forth rapidly and abnormally, and the disc contacts the valve seat during the movement.

38. The flap of the flutter: The safety valve moves back and forth rapidly and abnormally, and the flap does not touch the valve seat during the movement.

39. Static characteristics: It refers that under the steady flow state, the functional relationship between the outlet pressure of the pressure-reducing valve and the inlet pressure and flow rate and other parameters.

40. Dynamic characteristics: It refers to the functional relationship between the outlet pressure and flow rate of the pressure relief valve under the sudden change of inlet pressure and flow rate or other disturbance factors.

41. Flow Characteristics: Under the steady flow state when the inlet pressure and other parameters are constant, it refers to the functional relationship between the outlet pressure of the pressure-reducing valve and the flow rate.

42. Pressure characteristics: Under the condition of steady flow, when the flow rate and other parameters are constant, it refers to the functional relationship between the outlet pressure and the inlet pressure of the pressure-reducing valve.

43. Static characteristic: It refers to the deviation under the steady flow state, the change value of outlet pressure caused by the change of inlet pressure and the flow rate of pressure reducing valve.

44. Flow characteristic: It refers to the deviation under the steady flow state. When the inlet pressure and other parameters are constant, the outlet pressure change value is caused by the change in the pressure-reducing valve flow rate.

45. Pressure characteristic: It refers to the deviation under the steady flow state. When the flow rate and other parameters are constant, the outlet pressure change value is caused by the change of inlet pressure of the pressure-reducing valve.

46. Relative static deviation: It refers to the ratio of static characteristic deviation of the pressure reducing valve to given outlet pressure.

47. Relative flow characteristic deviation: It refers to the ratio of the flow characteristic deviation of the pressure reducing valve to given outlet pressure.

48. Relative pressure characteristic deviation: It refers to the ratio of the pressure characteristic deviation of the pressure reducing valve to the given outlet pressure.

49. Pressure growth coefficient: It refers to the growth rate of the outlet pressure when the pressure of the pressure-reducing valve drops from the rated value to zero (less than the allowable leakage).

50. Maximum flow: Under a given outlet pressure, when its deviation is within the specified range, the upper limit of flow can be reached.

51. Pressure reduction ratio: It refers to the ratio of absolute pressure at the inlet and outlet of the pressure reducing valve.

52. The outlet pressure: When the pressure medium stops flowing and the pressure reducing valve is completely closed.

53. Maximum allowable pressure: The maximum pressure represents that the trap shell can bear for a long time at a given temperature.

54. Working pressure: The pressure at the inlet of the trap under working conditions.

55. Maximum working pressure: Under the condition of the correct action, the highest pressure is at the inlet end of the steam trap. It is given by the manufacturer.

56. Minimum working pressure: Under the condition of correct action, it refers to the minimum working pressure at the inlet end of the steam trap.

57. Working back pressure: under working conditions, it refers to the pressure at the outlet of the steam trap.

58. The highest working backpressure: It is the highest pressure at the outlet of the steam trap when it can act correctly under the highest working pressure.

59. Back pressure rate: It refers to the percentage of the working back pressure to the working pressure.

60. The highest backpressure rate: It refers to the rate of the highest working backpressure to the highest working pressure.

61. working pressure difference:  It refers to the difference between the working pressure and the working backpressure.

62. Maximum differential pressure: It refers to the maximum difference between the working pressure and the working backpressure.

63. Minimum differential pressure: It refers to the minimum difference between the working pressure and the working backpressure.

64. The working temperature: It refers to the temperature at the inlet of the steam trap under working conditions.

65. Highest working temperature: It refers to the saturation temperature corresponds to the highest working temperature and pressure.

66. Maximum allowable temperature: It refers to the highest temperature that the steam trap shell can endure for a long time under a given pressure.

67. Valve opening temperature: It refers to the inlet temperature when the steam trap is opened during the drainage temperature test.

68. Valve closing temperature: It refers to the inlet temperature when the steam trap is closed during the drainage temperature test.

69. Drainage temperature: It refers to the temperature at which the steam trap can continuously discharge hot condensed water.

70. Highest drainage temperature: It refers to the highest temperature at which the steam trap can continuously discharge hot condensate under the highest working pressure.

71. The supercooled degree: It refers to the absolute value of the difference between the supercooled condensate temperature and the saturation temperature under the corresponding pressure.

72. The valve opening supercooled degree: It refers to the absolute value of the difference between the valve opening temperature and the saturation temperature under the corresponding pressure.

73. Maximum supercooling degree: It refers to the maximum value of the supercooling degree of the valve opening.

74. Minimum supercooling degree: It refers to the maximum value of the supercooling degree in closing the valve.

75. The displacement of cold condensate: It is the largest volume for the drain valve to discharge condensate within 1h under the given pressure difference and 20℃.

76. The displacement of hot condensed water: It is the largest volume that the steam trap can remove the condensed water within 1h under the given pressure difference and temperature.

77. Steam leakage amount: It refers to the amount of fresh steam leaked from the trapper unit time.

78. No-load steam leakage: It refers to the steam leakage before the steam trap is in full saturated steam condition.

79. Load steam leakage: It refers to the steam leakage of a steam trap under a given load rate.

80. Non-load steam leakage rate: It refers to the percentage of non-load steam leakage and the corresponding maximum pressure hot condensate water displacement.

81. The percentage of the loaded steam leakage: It refers to the rate and the actual hot condensate displacement in the test time.

82. The load rate: It refers to the percentage of the actual hot condensate displacement in the load rate test time and the maximum hot condensate displacement under the test pressure.