1. The single-seat control valve has a valve core and a valve seat in the valve body, which has the characteristics of small leakage. It is only suitable for clean medium occasions with strict leakage requirements and low pressure difference.
Among them, the pneumatic single-seat control valve is small in shape, light in body, high performance, and large in capacity. It is a new generation of general control valve products that meet the IEC standard. It is suitable for production process systems of general fluid media and process conditions. The single-seat control valve is a pressure-balanced control valve with a compact structure. It has an S-streamlined channel. It is also equipped with a guide vane to improve the balance flow of the fluid around the sleeve, so that the pressure drop loss is small, and the flow rate is large. Wide tuning range.
2. The double-seat control valve has the advantages of large rated flow coefficient and small unbalanced force. Therefore, it is widely used. Among them, the pneumatic double-seat control valve is suitable for those with less strict requirements on leakage and large pressure difference between the front and rear of the valve. Clean medium occasions.
3. Sleeve control valve adopts balanced spool with small unbalanced force, large allowable pressure difference, stable operation, large spool guiding surface, which can improve oscillation caused by eddy current and impact, simple structure, convenient assembly and disassembly and maintenance.
The water pressure test of the valve body includes the pressure test of the valve body and the leakage test when the valve core is fully closed. Normally, when the design pressure of the control valve exceeds 10MPa, the valve body must undergo a pressure test to inspect the valve body. The pressure resistance of itself and the upper valve cover.
1. Problems that should be paid attention to during pressure test of regulating valve.
(1) The pressure test of the regulating valve body adopts a manual pressure test pump for water pressure test, and it is strictly prohibited to use an electric pressure test pump.
(2) The test medium is clean water.
(3) The test pressure is 1.25 times the design pressure.
(4) The pressure self-operated control valve meter used for pressure test should be qualified, its accuracy should not be lower than 1.5 grade, and the upper limit of the scale should be 1.5 to 2 times of the test pressure.
(5) The valve core is opened at least 20% during the pressure test of the pneumatic valve. This must be kept in mind to prevent the valve core from being damaged by excessive pressure on one side. Normally, the valve core is adjusted A certain amount of leakage is allowed. According to the difference in the leakage level of the regulating valve, it is generally only required to conduct a leak test on the regulating valve with high differential pressure (V, VI leakage).