1. The Classifications of Globe Valve
Direct Globe Valve: The direct globe valve has small friction between the sealing surfaces during the opening and closing process, with wear resistance, small opening height and good manufacturing performance, which is one of the most widely used valves in industry, but it has the greatest resistance compared with other globe valves.
Oblique Globe Valve: In an oblique and Y-type globe valve, the flow passage of the valve body forms a diagonal line with the mainstream passage, so that the failure degree of the flow state is smaller than that of the conventional globe valve, and therefore the pressure loss through the valve is also reduced accordingly. It is often used in fluids containing solid particles or high viscosity.
Angle Globe Valve: In an angle globe valve, the fluid needs to change its direction only once so that the pressure drop through the valve is smaller than the globe valve of the conventional structure.
Plunger Globe Valve: This form of globe valve is a variant of the conventional globe valve. The valve is mainly used for opening and closing, but if equipped with a special type of plunger and sleeve, it can also be used to regulate the flow.
2. The Advantages of Globe Valve
1) The structure is simple, convenient to manufacture and maintain.
2) The working stroke is small and time of opening and closing is short.
3) Fine sealing performance, low friction between sealing surfaces, long service life.
3. The Disadvantages of Globe Valve
1) The resistance of the fluid is large, and the force required when it is opened and closed is greater.
2) Not suitable for medium with particles, high viscosity and easy coking.
3) Poor adjustment
4. Selection Principles of Globe Valve
1) A globe valve should be used on the pipeline or device of high-temperature and high-pressure medium. Such as high-temperature, high-pressure pipelines of thermal power plants, nuclear power plants and petrochemical systems.
2) Suitable used on where flow resistance on the pipeline is not strict, that is to say, the pressure loss is not considered.
3) There is flow regulation or pressure regulation, but the adjustment accuracy requirements are not high, and the pipe diameter is relatively small, like the nominal diameter ≤ 50mm pipeline, which is appropriate to choose globe valve.
4) For water supply and heat supply projects in urban construction, pipeline with smaller nominal diameter usually be used, and globe valve, balanced valve and plunger valve can be adopted.