2013年9月24日星期二

The advantages of gate valves

As a kind of gate valves, all processed with forging material of gate valves are collectively referred to as forged steel gate, forgings materials have A105, F11, F5, 304, 304 l,316, 316 l, etc. Domestic often say forged steel gate valves are normally refers to forged steel gate, small diameter range: DN10 Gate valves work environment.
Forged steel gate valve is suitable for Class150 ~ 2500-29, working temperature to 425 ℃ (carbon steel) or - 29 ~ 500 ℃ (stainless steel) of small diameter pipe, used to truncate or on line in the medium, choose different material, can be respectively suitable for water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea and other media. Applied on the oil pipeline path.
Forged steel gate valve are designed for dalian type reducing, and compared with diameter cast steel gate valves of the flow rate is smaller, but the pressure and temperature range is higher than the cast steel valves, the sealing performance is much better than cast steel gate valves, longer life, the medium flow direction as well as other electric three way control valve is not restricted.
China gate valve installation points
1, installation location, altitude, direction of import and export must comply with the design requirements, should firmly close connection.
2, all kinds of manual valves installed on the thermal insulation pipe, handle down is not allowed.
3, the valve before installing a visual inspection must be conducted. ZhuGanGuan for working pressure is greater than 1.0 MPa and the valve with the function of cutting off, before the installation should be strength and tight performance testing, qualified rear prospective use. Strength test, the test pressure is 1.5 times the nominal pressure, duration of not less than 5 min, shell and packing shall be no leakage of valve shall be qualified. Leak test, the test pressure is 1.1 times the nominal pressure; Test pressure in the duration of the test should comply with the standard of GB 50243 requirements, qualified for damper seal face no leakage.
Forged slab gate valve often ignore the problem of grease injection rate. Note oil, grease gun operator select valves and greasing connection, on the operations. There are two forged steel gate valve: on the one hand, on the quantity is little greasing, sealing surface due to the lack of lubricant and speed up the wear and tear. On the other hand on the excess, resulting in waste. Is that no categories depending on the type of valve, valve sealing capacity of different calculations. Can calculate a seal to the valve size and category capacity, reasonable injection again just the right amount of grease.
Forged steel gate valve often ignore the pressure problem. In the greasing operation, on the pressure gauge half free floating ball type steam trap law changes in peak valley. Or safety valve leakage pressure is too low, seal failure, the pressure is too high, on the lipids within the valve manufacturer jams, seal hardening or sealing ring and valve ball, valve plate lock. Usually fat injection pressure too low, inject grease into the valve at the bottom of the cavity, more commonly occur in the small gate.

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