What is a marine valve
Marine valves are equipment that controls the pressure, flow and flow direction of the fluid in the ship’s pipes in order to meet the environmental conditions of the ship. A valve is a control device for a fluid pipeline. The basic function is to open or block the flow of the pipeline medium, change the flow direction of the medium, adjust the pressure and flow of the medium, and protect the normal operation of the pipeline equipment.
Overview of Marine Valve Technology Development
Since the birth of the People’s Republic of China, my country’s marine valve technology has achieved rapid development. Through the transfer of early Soviet products, major auxiliary sintering, serialization and standardization, and self-research and design, it has basically met the needs of my country’s shipbuilding industry. A total of 12 universal valves have been designed. Category, 1400 specifications. The maximum pressure of the valve is 25MPa, and the maximum diameter is 900 mm. Valve materials include cast iron, carbon steel, alloy steel, copper alloy, aluminum alloy, titanium alloy, stainless steel, non-metal, etc. Applicable media mainly include fresh water, sea water, air, steam, fuel, lubricating oil, etc.
Since the 1970s, ball valves and butterfly valves, which have the advantages of light weight, small size, good sealing performance, fast opening and closing, and convenience, have been gradually applied to ships, and more and more stop valves and gate valves will be replaced to improve ships. performance. Electric gate valves, electric shut-off valves, electric shut-off valves, electric ball valves, electric butterfly valves, pneumatic butterfly valves and other remote control valves are gradually being used by some ship systems. The hydraulic valve remote control system is used to improve the modernization of ships. The performance required by the ship’s various systems requires high-pressure butterfly valves, pilot-type full-start safety valves, seawater solenoid valves, high-pressure electric ball valves, rotary hydraulic gate valves, special pressure reducing valves, temperature control valves, high-pressure air solenoid valves, large displacement traps, and ventilation Special valves such as butterfly valves can be developed by ourselves or provided for use on ships.
Classification and usage
1. According to the channel direction of the shut-off valve, it is divided into:
1. Straight-through globe valve
2. DC shut-off valve: In the DC or Y-type shut-off valve, the flow channel of the valve body and the main flow channel are inclined at a certain angle, and the damage degree of the flow state is less than that of the traditional shut-off valve, so the pressure loss through the valve will be reduced accordingly.
3. Angle cut-off valve: In the angle cut-off valve, as long as the fluid changes its direction once, the pressure drop through the valve will be smaller than that of the general structure of the cut-off valve.
4. Plunger stop valve: This form of stop valve is a deformation of ordinary stop valve. On this valve, the valve and the valve are designed according to the plunger principle. The valve is polished with a plunger and connected to the valve, and the seal is composed of two elastic seals sleeved on the plunger. The two elastic seals are separated into a ring, and the load imposed on the valve cover by the valve nut firmly presses the seal around the piston. The elastic seal can be replaced and can be made of a variety of materials. The valve is mainly used to “open” or “close”, but there are also special forms of plungers or special rings that can be used to adjust the flow. It can be separated according to the position of the screw on the stem of the shut-off valve.
1. Upper screw valve shut-off valve: The screw on the stem of the shut-off valve is on the outside of the valve. The advantage of the valve is that it is not corroded by the media and is easy to lubricate. This kind of structure is more common.
2. Hanasa valve cut-off valve: the screw of the stem of the cut-off valve is inside the valve. The valve thread of this structure is in direct contact with the medium, which is easy to be corroded and cannot be lubricated. This structure is used in places with small diameters and low temperatures.