Experimental study on the influence of the sealing surface width of the shut-off valve on the leakage amount Liu Feng, He Ju (Petroleum University Machinery Plant (East China), Dongying, Shandong 257062, China) increased the law, and summed up the approximation of the relationship between the leakage of various caliber valves and the width of the sealing surface formula.
The cistern unloading stop valve is a new type of patented stop valve 240209.4), its closing direction is consistent with the system pressure direction, and the sealing effect is better. The valve disc seal material is rubber, and the sealing performance is good, but the use temperature and pressure are limited. In order to expand the range of use of such valves, the valve disc seal material is 3Cr13, and the seat seal material is D507Mo. In the process of determining the width of the seal pair, the leakage amount, the seal pair width and the valve diameter are derived through a series of tests. The relationship between.
2 The test unit is simplified when tested. In the case of system pressure, liquid viscosity and related physical properties such as sealing materials, only the effect of valve sealing surface width and caliber on leakage is investigated. The test system pressure is 25 MPa and the medium is 20 C water. Sealing surface A material is 3Cr13, quenching treatment, hardness HRC40~45, roughness Ra0. 4um, flatness 0.05mm. sealing surface B material is D507Mo, tempering treatment, hardness HRC35~38, roughness Ra0.4um, flatness 0.05mm. Since the sealing direction of the valve is consistent with the pressure direction of the system, the two sealing pairs are naturally pressed under the action of the system pressure, and no additional sealing force is added.
3 Test data After a series of tests, the data of the relationship between the sealing surface width and the leakage amount of different caliber valves are obtained, and the approximate calculation of male and female engineers is mainly engaged in the design and manufacture of valves.
Sealing surface width H/mm leakage amount Q/mm3.s1 sealing surface table 2DN80mm sealing sub-test data sealing surface leakage amount sealing surface leakage amount sealing surface leakage amount width width table 4DN150mm sealing sub-test data sealing surface width H/mm leakage sealing Surface width H/mm leakage amount Sealing surface width H/mm leakage amount Miscellaneous cover width H/mm DN50mm sealing pair width and leakage amount relationship DN80mm sealing pair width and leakage amount sealing surface leakage amount sealing surface leakage amount sealing surface leakage Width Q/mm3. Width Q/mm3. Width Q/mm3.H/mms1H/mms1H/mms11328. Sealing surface width H/mm DN100mm sealing pair width and leakage amount 4 Test analysis explained by capillary principle, sealing pair periphery The amount of leakage per unit length is proportional to the product of the capillary diameter of the fourth power, the viscosity of the liquid, and the pressure difference across the seal pair. From the test data analysis, the amount of leakage is not completely inversely proportional to the width of the sealing surface. Because the change in the width of the sealing surface affects the sealing specific pressure, which affects the capillary diameter. The results of this test are closer to the actual situation.
5 Conclusion From the test data, it can be seen that for the sealing surface of the determined caliber, as the width of the sealing surface increases, the leakage amount gradually decreases. When the reduction is made to a certain extent, the leakage amount is gradually increased, and the width of the sealing surface which minimizes the leakage amount is referred to as the minimum leakage point width. From the sealing test of different calibers, as the diameter is increased, the minimum leak point width is also gradually increased.
Valve test bench interface Ye Sheng (Yongjia County Quality Inspection Institute, Zhejiang Yongjia 325102) Today, the modern industrial high development, the valve is one of the indispensable accessories. There are many kinds of valve products produced by various companies. If they are classified according to the way of connecting with pipes, they can be divided into flange connection, butt welding connection, clamp connection, ferrule connection, bellows connection and thread connection. Therefore, the products tested by the quality inspection department also contain the valves of the above different connection methods. If different test devices are provided for each valve connection interface, this not only wastes manpower and material resources, but also occupies a large installation space, which brings trouble to the base quality inspection department to detect a special type of valve. According to the actual needs, a valve test bench capable of detecting various interfaces was designed.
The valve test bench consists of two parts, one is the medium supply part (usually refers to the test medium such as water, air and other supply parts), using a universal device. The second is the valve clamping part, which is designed with a device that can install different interfaces.
a is a conical top connection structure, when the valve for detecting the butt joint or the bellows is connected, the cone head is fixed in the test 1. The sealing ring 2. The test station interface cone top connector (b) the screw connector flange connector valve The interface of the test bench interface structure station. b is a threaded joint that is replaced when the threaded valve is tested. c is the flange connection joint. When detecting the flange connected valve, fix the flange to the test bench interface. When the same type of valve is different in size, it can be configured with various specifications. After the actual operation and application, the device has a good effect, and solves the problem of repeated device configuration that is common in the detection department.
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