Detailed method of testing steam inlet trap
1 Scope This specification specifies the implementation methods and test settings of steam traps.
This standard applies to the factory test and type implementation of machine-type, thermostatic and thermal energy steam traps (hereinafter referred to as traps).
2 Implementation equipment 2.1 Operational implementation, minimum working pressure implementation, maximum working back pressure implementation and maximum working pressure implementation.
2.2 The experimental device for the implementation of steam leakage, the implementation of the solidified water displacement, the implementation of the drainage temperature and the implementation of the maximum drainage temperature
2.3 General requirements of the test device a) The volume of the low-pressure tank is not less than 2m3;
b) the volume of the back pressure tank is not less than 1m3;
c) the volume of the measuring barrel is not less than 0.2m3;
d) The accuracy of temperature, pressure and weight measuring instruments is not less than 0.5, the accuracy of timing instruments is not less than ¡À 0.2%, and the resolution is slightly less than 0.1s;
e) All hot pipelines and equipment in the installation shall be insulated.
3 Implementation methods 3.1 Shell implementation a) Implementation medium: water, oil, or other liquid with a viscosity not greater than water;
b) Experimental pressure: 1.5 times the nominal pressure;
c) Medium temperature: normal temperature;
d) Apply the experimental pressure to the assembled trap valve with the inlet opening. During the time specified in Table 1, there must be no leakage in the shell and no residual deformation of the internal parts.
Nominal diameter / DN test continues to year / s
65 ～ 150> 60
Note: When using gas such as steam, air, etc., there should be safe method, and some relevant approvals should be obtained.
3.2 Steps When introducing steam to the trap valve, the trap valve should be opened. When hot melt water with a certain load rate is introduced, the trap valve should be opened (the time required for opening varies with the type of trap valve). The valve should be re-blocked. A maximum of 3 complete cycles are performed before this test is considered complete.
Machine type traps with sealing pairs lower than closed floats and intended to adhere to water seals can be tested with atmosphere and water development.
For disc traps, when the inlet is in a pure steam form, the valve plate bounce frequency is not greater than 3 times / min.
Regarding the trap with a large degree of subcooling, the blocked subcooling degree is not greater than the given value of the scheme.
3.3 The minimum task pressure is to develop an action experiment according to the prescribed moment of 3.2, and at the same time, gradually increase the experimental pressure to the minimum task pressure. The trap should be able to open and close accurately during the entire lift.
3.4 Execution of the highest task pressure Perform the step experiment according to the rules of 3.2, and gradually increase the implementation pressure until the highest task pressure. The trap should be able to open and close accurately during the entire implementation process.
3.5 Maximum task back pressure experiment Under the highest working pressure, develop the step test as described in 3.2, and at the same time, gradually increase the true pressure at the outlet of the trap until the trap cannot be accurately opened and closed. The fastest port pressure at which the trap can still open and close accurately is equal to the highest task back pressure.
3.6 Exhaust air skills The trick test is to pass air to the trap with no more than 0.3 MPa. The trap should be able to discharge the atmosphere. The trap should be temporarily closed within 5 minutes, but the blocking time should not be greater than 1 minute.
3.7 Drainage temperature The steam is passed to the trap to block it. After that, molten water saturated with temperature is introduced. Assume that the trap cannot be opened immediately. Wait for the trap to gradually cool down until the trap is actively opened. The temperature of the inlet melted water at the time of opening is equal to the valve opening temperature. In the future, the temperature of the condensed water will be gradually increased until the trap is passively opened, and the temperature of the condensed water at the inlet when the valve is closed is the valve closing temperature.
3.8 Steam Leakage Under the given task pressure, the condensate water with a load rate of (6 ¡À 3)% is introduced into the trap, and at the same time, it is filled with steam, and the melted water passing through the trap is discharged into the designated capacity. Calculate the amount of steam leakage in the measuring barrel using the thermal equilibrium method. The method of implementing the steam leakage amount is in accordance with the delineated example moments in Appendix A.
3.9 Thermal condensate water discharge The performance of thermal condensate water discharge is the amount of hot melt water discharged in the unit year measured at the pressure difference and the temperature of the condensed water. The displacement of hot condensate under differential pressure should be measured under the same subcooling. Under normal circumstances, the hot melt water displacement test can make the inlet end of the trap open to the atmosphere. The implementation method of the hot-melt water displacement shall be determined in accordance with Appendix B.
Note: The above 3.3 ～ 3.8 are not applicable to pulse type and orifice plate type traps.