Selection principle of pressure reducing valve for industrial steam pipeline
Pressure stability and sensitivity to the pressure response after the valve depends on the ratio between the piston chamber or diaphragm chamber and the diameter and opening of the guide valve. The larger the ratio is, the better the stability is, but the worse the sensitivity is, and vice versa. So manufacturers in the design of pressure relief valve, need to do a comprehensive consideration of two factors, stability and sensitivity of the balance, the ratio should not be too large or too small. Too much proportion will cause slow response, pressure drop, unable to recover in time; Too small ratio will cause pressure in a small range of frequent beating, resulting in internal parts wear and tear, leading to reduced valve life. Therefore, Valve manufacturer in the production and development of pressure relief valve, must take into account the stability and sensitivity of the two requirements. At present, the design of more perfect pressure relief valve, have been completely solved these problems. However, considering the requirements of field working conditions and secondary pressure, diaphragm type is suitable for some working conditions, while piston type is suitable for some working conditions. The selection principle of steam pressure reducing valve according to the use requirements of the selected type and pressure regulating accuracy, and then according to the required maximum output flow to choose its size. When determining the air source pressure of the valve, it should be greater than the output pressure of 0.1mpa. The steam pressure reducing valve is generally installed after the water filter, before the oil mist or value setting device, and pay attention not to the inlet and outlet of the reverse connection; The knob should be relaxed when the valve is not in use, so as not to affect the performance of the diaphragm due to its frequent deformation under pressure.
Principles for selecting pressure-reducing valve for industrial steam pipelines
1) the fluctuation of the inlet pressure of the steam reducing valve should be controlled at 80% ~ 105% of the given value of the inlet pressure. If the range is exceeded, the performance of the reducing valve will be affected.
2) in general, the pressure behind the valve of the steam reducing valve Pc should be less than 0.5 times the pressure before the valve, that is, Pc< 0.5p1. Each spring of the steam reducing valve is only applicable to a certain outlet pressure range, beyond which the spring should be replaced.
3) in the medium working temperature is relatively high occasions, the general selection of pilot piston type steam pressure reducing valve or pilot bellows steam pressure reducing valve.
4) medium for air or water (liquid) occasions, generally appropriate to choose the direct action of the film type pressure-reducing valve or pilot film type pressure-reducing valve.
5) medium for the occasion of steam, should choose the pilot piston type steam reducing valve or pilot bellows reducing valve.
6) for the convenience of operation, adjustment and maintenance, the steam pressure reducing valve should be installed in the horizontal pipe.