Archive for month: September, 2019

Industrial processes frequently use steam at lower pressures and temperature. The steam is used for cleaning, heating, and humidification in the application of powering turbines to generate electricity. The steam pipeline of power plant requires some control and steam control to reduce the pressure and temperature of the inlet stream for process application.

In general, a complete steam station system must be equipped with the valve below: main control valve, control valve of each branch, steam pressure reducing valve, steam trap (drain water valve) according to the length of the pipeline, the bleeding valve in the pipeline end. Though most types of valves can control steam flow, special service conditions exist with steam regarding temperature and pressure. The most commonly used steam valves are pressure reducing valve and drain water valve.

 

Pressure reducing valve

A steam pressure-reducing valve is an indispensable part of many steam systems. It plays a critical role by providing stable steam pressure and reduces the temperature to process applications in a process plant.

When the steam transmitted from the high-pressure boiler, the reducing valve control often used, which can reduce the size of the boiler and improve the steam dryness, convenient for long-distance transmission. Due to the high steam density at high pressure, the pipe with the same diameter can transport more high-pressure steam than low-pressure steam, thus reducing the size of the pipe and saving the cost.

Drain water valve

A steam trap is a kind of valve which can automatically remove condensed water and other non-condensing gas from the steam pipe and steam equipment and prevent steam leakage. The water to be discharged mainly comes from the condensate water at the bottom of the boiler cylinder, the condensate water at the bottom of the workshop cylinder, the condensate water of the steam separator before decompression and the condensate water of the conditioner sub-cylinder. According to its operation principle, there are mainly floating ball drain water valve, thermodynamic drain water valve, thermostatic drain water valve, inverted bucket drain water valve and so on.

 

In addition, you can also choose a gate valve and globe valves when the steam pipe temperature is less than 425℃. Gate valve is mainly used for steam pipeline where no need frequent open or closure; The globe valve offers a better function of flow regulation. Butterfly valve is not recommended to be used in steam pipeline, because the high pressure inside the valve, it’s difficult to switch  and the sealing surface is easy to damage, so it cannot be frequently switched, so the butterfly valve does not put up good performance as the gate valve; However, if the pipeline pressure is not very high (below 6.4 Mpa), it can also be used, but it is recommended to use metal hard seal butterfly valve because of the high temperature. You can choose the eccentric valve with a WCB material body, installation should pay attention to the flow direction, the pipeline should be kept clean to prevent the tight close.

 

In short, selection of valve for steam service depends on the purpose of the valve, pipe diameter, temperature and cost. As an industrial valve manufacturer,  any valve needs, call us today!