Types and uses of ball valves

(1) Insulation ball valve

For the occasion of transporting private and dense fluids such as urea, which are easy to form, such as waxy and leached high oil, the heat preservation method is often adopted to prevent low fluid viscosity, increase fluidity, avoid cold blockage of valves and reduce power consumption of engineering. There are two kinds of heat preservation ball valves according to heating mode: external heating type and internal heating type.

1. External Heating Insulation Ball Valve

Generally known as jacket type heat preservation ball valve, the whole structure of the valve body is used, the ball and seat are loaded from the side, and the plug is used to hold and press the sphere in the zone as a floating type. The heat preservation sleeve is made of the casting Genggang pepper pressure welding towel. The jacket is provided with a nozzle for the introduction or push-out of heating water vapor. This kind of heating and insulation ball valve has simple structure and convenient manufacture, but it has large size, large heat loss and low heating efficiency.

2. Internal Heating Insulation Ball Valve

The sphere is made into a hollow sandwich, which is heated by steam or resistance wire. Although the structure of the internal heating type heat preservation ball valve is complex and difficult to manufacture, it has small size and high heating efficiency.

(2) Corrosion-resistant lined ball valves

For the occasion of conveying strong corrosive media, such as sulphuric acid, nitric acid, hydrochloric acid and other media, stainless steel and other corrosion-resistant metal materials can be used, but the cost is high. If the lined ball valve is used, it not only has excellent corrosion resistance, but also saves precious metals, so it is an ideal corrosion-resistant valve.

The body, sphere and stem of the corrosion-resistant lining ball valve can be made of cast iron and cast steel to withstand medium pressure. The surface of the parts directly contacted with the corrosive medium is lined with a layer of plastics, such as F-3 and F-46, with a thickness of 2-3 mm, to resist medium corrosion and achieve reasonable material use.  In recent years, a kind of sprayed plastic ball valve has appeared, that is, spraying polyphenylene sulfide and other corrosion-resistant plastics on the above-mentioned lining plastic parts can meet the above requirements, and its manufacturing cost is lower.

(3) Wear-resistant ball valves

For conveying high hardness granular media, such as alumina, pulverized coal and other media, its hardness often reaches HRC60 or more. The universal metal sealing ball valve is used, and its sealing pair can not withstand the erosion of medium for a long time. Usually, this kind of wear-resistant ball valve can be treated by spraying superhard materials such as WC/Co on the ball valve and seat.

(4) Receiving and receiving ball valves

The successive and alternate transportation of different oil products in a pipeline is called sequential transportation of oil products. As shown in Fig. 2-71, in order to reduce oil contamination, at the starting point of the pipeline, a number of isolation balls should be placed at the interface of the two kinds of oil by using the receiving and receiving ball valves; after passing through the intermediate pumping station, the isolation balls should be removed by using the receiving and receiving ball valves, replacing the new isolation balls, or making the old isolation balls continue to run across the terminal. Remove the isolation ball with the receiving and receiving ball valve.

(5) Multi-function ball valve

In order to simplify the process flow, facilitate operation and control, and reduce the amount of valves, multi-function valves or multi-purpose valves have emerged. If the shut-off check valve is usually used, it is to turn the shut-off valve into a lift check valve, which has two functions. In recent years, the trend of ball valves to multi-function valves has been developed, such as butterfly ball valves and check ball valves.

(6) All Plastic Ball Valve

Full plastic ball valves were produced in the 1980s with the development of the plastic industry. Compared with metal ball valves, the most remarkable advantages are:

Lightweight, handy, beautiful and durable. Full plastic ball valves are especially suitable for acid-base medium of low pressure (PN IMPa) and suspension (80).

Water treatment system and pickling equipment. The body, sphere, stem and connecting nut of this kind of ball valve are manufactured with ethylene in the dressing atmosphere and polymer surface. The seat seal ring is made of polytetrafluoroethylene. At present, DN15-100mm global valve can be manufactured in China.