Brief introduction of globe valve
The open-close disc of globe valve is the plug style valve clack with flat or cone sealing surface. The valve clack move in a straight line along with the centerline for fluid.
The motion forms of valve stem of globe valve has lift rod type (the valve rod lifting and drop while the hand wheel not, common name: non-rising stem), also has lift rotating rod type (hand wheel rotate lifting together with valve rod, the nut is installed on the valve body, common name: rising stem).
Globe valve belongs to sealed type valve, so when close the valve, pressure are bring to the valve clack for mandatory non-leakage between the sealing surface. The flow direction of globe valve all shall be top-down. When opened the globe valve and the opening height of valve clack is 25% ~ 30% of nominal diameter, the quantity of flow has reached the maximum which mean that the valve has reached the full open position. Therefore, the fully open position of valve should be determined by the stroke of valve clack.
Advantages of globe valve
1. Simple structure, convenient manufacture and maintenance.
2. Small working stroke, short opening and closing time.
3. Good sealing, small friction between sealing surface, long service life.
Disadvantages of globe valve
1. fluid resistance, large the required power for opening and closing.
2. Not apply to the medium with particles, large viscosity and easy coke.
3. Poor regulation performance.
Classification of globe valve
The screw thread position of valve: outer thread type and inner thread type globe valve;
The flow direction of medium: straight-through type globe valve, straight-flow type globe valve, angle type globe valve, plunger type globe valve;
Purpose: fluorine lining globe valve, national standard globe valve, needle type globe valve, low-temperature globe valve, plunger type globe valve, insulation jacketed globe valve, forged steel globe valve, oxygen special-used globe valve, bellows globe valve;
Sealing form: packing seal globe valve and bellows seal globe valve.
Structural features of globe valve in Hydropower station
1. It is reasonable in structure, excellent in performance and delicate in appearance according to the GB12235 national standard.
2. The sealing surface of valve clack and valve seat adopt satellite cobalt-based cemented carbide surfacing with good abrasion resistance.
3. Through hardening and tempering,surface treatment in nitrogen, the valve rod has good high corrosion resistance and abrasion resistance.
4. Variety piping flange standard and flange sealing surface model can be used to meet the needs of the various engineering and user requirements.
5. The material of valve body is complete, the packing and gasket are reasonable equipped according to actual working condition or user requirements. The electric welded globe valve is suitable for the working condition with all kinds of pressure, temperature and medium.
6. Reversed sealing is formed by screw thread connecting the sealing seat or the ontology surfacing austenitic stainless steel. It is reliable, the replacement and maintenance of packing can be proceeded without stop, which is convenient and efficient and will not affect the system operation.
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Partner with Addnew Hydropower Limited and benefit from the following advantages in hydropower business:
> Water-to-wire total solutions and complete plant integration;
> High levels of quality, performance and reliability;
> 36-year expertise and experience from more than 1,000 successful projects;
> Competitive prices from efficient management;
> Promptness in both equipments' delivery and technical support.