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|Inner package:plastic bag sealed package Outer package:carton package or wooden case package The lettering, nameplate, certificate for cryogenic valves are available We can customize the package for globe valve;
|L/C, D/A, D/P, T/T, Western Union, MoneyGram
|100pcs one day
|Stainless Steel -196 Industrial Cryogenic Types Low Temperature Globe Valves
|Low Temperature Globe Valves
|Cryogenic Types Low Temperature Globe Valves
cryogenic flow control valve,
20MPa cryogenic globe,
PCTFE Disc Seal Cryogenic Globe Valve
Stainless Steel 304 /316 Low Temperature PCTFE Disc Seal Cryogenic Globe Valve
According to this movement form of the valve flap, the change of the valve seat port is directly proportional to the stroke of the valve flap. The valve stem axis of the globe valve is perpendicular to the sealing surface of the valve seat. The opening or closing stroke of the valve stem is relatively short, and it has a very reliable cut-off action, making this valve very suitable as a medium for cut-off or adjustment and throttling. Once the valve flap of the globe valve is in the open state, there is no longer contact between its valve seat and the sealing surface of the valve flap, and it has a very reliable cutting action. Therefore, this valve is very suitable as a medium for cutting or adjusting Stream usage. Once the shut-off valve is in the open state, there is no contact between its seat and disc sealing surface, so its sealing surface wears less mechanically, because most seats and flaps of the globe valve are easier to repair or replace It is not necessary to remove the entire valve from the pipeline when sealing the element, which is very suitable for the case where the valve and the pipeline are welded together. The flow direction of the medium changes through such valves, so the flow resistance of the shut-off valve is higher than other valves.
|SPECIFICATIONS FOR CRYOGENIC CHECK VALVES
|Stainless Steel 304 /316 Low Temperature PCTFE Disc Seal Cryogenic Globe Valve
|PCTFE Disc Seal Cryogenic Globe Valve
|Low Temperature Cryogenic Globe Valve
|-196 °C- +80°C
Holding point of low temperature globe valve:
(1) The structure is simpler than the gate valve, and it is more convenient to manufacture and maintain.
(2) The sealing surface is not easy to be worn and scratched, and the sealing is good. There is no relative sliding between the valve flap and the sealing surface of the valve body when opening and closing, so the wear and scratch are not serious, the sealing performance is good, and the service life is long.
(3) When opening and closing, the flap travel is small, so the height of the shut-off valve is smaller than the gate valve, but the structural length is longer than the gate valve.
(4) The opening and closing torque is large, the opening and closing is more laborious, and the opening and closing time is principal.
(5) The fluid resistance is large, because the medium channel in the valve body is tortuous, the fluid resistance is large, and the power consumption is large.
(6) Media flow direction When the nominal pressure PN≤16MPa, generally use co-current flow, and the medium flows upward from below the valve flap; when the nominal pressure PN≥20MPa, generally use reverse flow, and the medium flows downward from the valve flap. To increase the sealing capacity. During use, the shut-off valve medium can only flow in one direction, and the flow direction cannot be changed.
1. Main material of cryogenic valve
1 Factors to be considered in the selection of main materials
From the metallographic point of view, in addition to austenitic steel with a face-centered cubic lattice, copper, aluminum, etc., general steel materials will exhibit low temperature brittleness at low temperatures, thereby reducing the strength and service life of the valve. When choosing the host material, first choose the material suitable for working at low temperatures. Aluminum does not exhibit low-temperature brittleness at low temperatures, but due to the low hardness of aluminum and aluminum alloys, the wear resistance and scratch resistance of aluminum sealing surfaces are poor, so the use of low-temperature valves has certain restrictions, only at low pressure and Used in small-diameter valves.
The material working at low temperature should ensure its low temperature performance, mainly to ensure its cold impact strength. The valve trim must be properly selected so that it has sufficient cold impact strength to prevent breakage. The alloy steel of c and cr quickly loses the impact strength when it is below -20℃, so the service temperature is limited to -30℃ and -50℃, respectively. Nickel steel with ni content of 3.5 can be used to -100 ℃, nickel steel with ni content of 9 can be used to -192 ℃. Austenitic stainless steel, nickel, Monel, Hastelloy, titanium, aluminum alloy and bronze can be used to a lower temperature -273 ℃.
In addition, the selection of materials for low-temperature valves should also consider the following factors: 1 the low service temperature of the valve; 2 the mechanical properties required by the metal materials to maintain working conditions at low temperatures, especially impact toughness, relative elongation and tissue stability ; 3 In the case of low temperature and oil-free lubrication, it has good abrasion resistance; 4 has good corrosion resistance; 5 when using welding connection, the welding performance of the material must also be considered.
2 Selection of materials for valve body, bonnet, valve seat and disc (shutter). The selection principles of these main parts and materials are roughly: ferrite steel is used when the temperature is higher than -100℃; temperature is lower than -100℃ Austenitic steel is used; low-pressure and small-caliber valves can be made of copper and aluminum. Choose appropriate materials according to the low operating temperature during design.
3 Material selection of valve stem and fastener
When the temperature is higher than -100 ℃, the valve stem and bolt materials are made of alloy steel such as ni, cr-mo, etc. After proper heat treatment, the tensile strength is improved and the thread bite is prevented. When the temperature is lower than -100℃, it is made of austenitic stainless acid-resistant steel. However, the low hardness of 18-8 acid-resistant steel will cause the valve stem and the packing to scratch each other, resulting in leakage at the packing. Therefore, the surface of the valve stem must be plated with hard chromium (plating thickness 0.04-0.06mm), or nitrided and nickel-phosphorus plated to increase the surface hardness. In order to prevent the nut and bolt from biting, the nut is generally made of mo steel or ni steel, and the surface of the thread is coated with molybdenum disulfide.
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