Amie Brewer Valves May 10th, 2019 - 14:00:35
Sealability and strength property are the most basic and most important characters for all valves. The sealing of a valve can be separated into internal seal and external seal. The front one means the sealing between valve clack and seat. The latter one means the sealing between the moving part of the valve stem and bonnet, body and bonnet, body and connection part. When the valve is used, it should be not only good in sealability but also be safe.
Likewise, there are other types of these valves that are available today, and that would be the lug style and the wafer style. The most popular would be the wafer style valve. This type would be under the plastic valve. In contrast, lug designed valves contain in them inserts made of metal, which are situated in the valve's bolt holes. The inserts are then eased into each end and through this method they would be permitted in a certain system using only dual bolts and without nuts.
Full port valves are used when there is a requirement of free flow rate of fluids. This valve has an oversized ball with a big hole to allow huge quantities to flow through it. But when there is a requirement of high pressure in the flow, reduced port valves are preferred. A common example is the pipe heads that are used for a car wash. As we require pressure in water flow, this type of valve is used in them. Trunnion ball valves have a disc or anchoring above and below the valve generally suitably when there is a large and high pressure flow rate requirement.
With the rapid development of different industries such as modern nuclear, petrochemical, electric and space, automatic control for process technology and long-distance fluid transportation, a lot of modern low-temperature valve, vacuum valve and control valve are in great need. So in order to ensure the good sealability and suitable strength of the above-mentioned valves, to develop new materials will be a great challenge. As it should be, just to improve the sealing ability and strength for future valves is not enough. It is suggested that the manufactures should expand other parameters of the valve and develop energy-saving, automatic and multi-functional valves, such as low-temperature one used for liquid oxygen, hydrogen or natural gas, vacuum valve, safe valve and so on
Valve response time is another important factor for us to consider. For optimum control of many processes, it is important that the valve reach a specific position quickly. A quick response to small signal changes is one of the most important factors in providing optimum process control. Valve response time includes both the valve assembly dead time, which is a static time, and the dynamic time of the valve assembly. It is important to keep the dead time as small as possible. Dead band, whether it comes from friction in the valve body and actuator or from the positioner, can significantly affect the dead time of the valve assembly.
Customers wanting the best in Needle Valves need look no further than Swagelok to meet all their needs. Swagelok Needle Valves are used in flow metering applications, where a constant, calibrated flow must be maintained. A Needle Valve has a long tapered point at the end of the valve stem that is lowered through the seat to restrict or block flow, as required, and a needle-shaped plunger on the end of the screw which exactly fits the point. Fluid flowing through the valve turns at 90 degrees, and passes through the orifice that is the seat for a rod with a cone shaped tip. The finely threaded stem, and large seat area allow for the precise calibration of resistance to flow. As the plunger is retracted, flow between is possible - until the plunger is completely retracted, fluid flow is impeded.