The diaphragm of the German DOLDR pilot diaphragm steam pressure reducing valve adopts new materials and increases the working area of the diaphragm, which is widely used in steam systems. Precise and stable pressure control can be achieved regardless of changes in steam pressure upstream of the valve or fluctuations in downstream loads. One of the outstanding features of the pilot diaphragm steam regulator is that one or more pilot valves can be installed or interchangeable on the same valve body, allowing for temperature control, upstream pressure control, or remote on/off control while stabilizing pressure reduction.
Parameter diagram of German doldr imported pilot diaphragm steam pressure reducing valve:
Working principle of German doldr imported pilot diaphragm steam pressure reducing valve:
The normal position before starting is that the main valve is closed and the pilot valve is opened by the action of spring force. Steam enters the main diaphragm chamber through the pilot valve and a portion of the steam flows out through the control orifice. When the steam flowing into the pilot valve is greater than the steam flowing out of the control hole, the control pressure in the main diaphragm chamber increases, and the main valve is opened. As the steam flows through the main valve, the increase of the downstream pressure is fed back to the lower part of the diaphragm of the pilot valve through the induction tube, which balances the spring compression force of the upper part of the diaphragm, so that the pilot valve gradually closes the throttling, so as to maintain the pressure in the main diaphragm chamber and control the opening of the main valve to convey the appropriate amount of steam. By adjusting the spring on the diaphragm of the pilot valve, the set pressure downstream can be changed. When steam is not needed, the pressure of the sensing tube increases, the pilot valve is closed, and the control pressure is released through the control hole, so that the main valve is tightly closed.
German Dodd Doldr pilot diaphragm steam pressure reducing valve selection
Selection principle: After the steam is depressurized through the pressure reducing valve, it will produce a higher flow rate due to expansion. Extreme flow rates through the seat of the regulator can make noise and erosion unacceptable. Therefore, its flow rate must be limited. In heating systems, it is generally recommended to limit the steam flow rate to between 20 and 30 ms. and for outdoor or already noisy environments. A higher flow rate can be selected.
For example, a steam heating system is known, the inlet pressure is 7 barg, the outlet pressure is 2 barg, and the flow rate is 440 kg h. Select the appropriate upstream and downstream pipe diameters. As can be seen from the above figure, the upstream pipe diameter is DN40. The downstream pipe diameter is DN65.