Three generations of temperature reduction and decompression device performance comparison table The temperature reduction and decompression device was introduced from the former Soviet Union in the 1970s by the valve factory of Zigong Power Station. As of now, it can be roughly divided into three generations of products.
The first generation is decompression and desuperheating. The decompression valve of the decompression system is mostly a single-stage piston plus orifice to complete the decompression. The desuperheating system is regulated by the throttle valve, stop valve and water supply. Valves or water distribution valves, check valves, pipes, mixing pipes, text pipes, etc. to complete the desuperheating; the disadvantages of the structure of the desuperheating and decompression device are complex structure, large area, inconvenient installation and maintenance, adjustment The narrow range, high noise, high failure rate; at the same time, the water in the pipeline can cause water hammer, cause vibration, and reduce the service life.
The second generation completes the decompression and desuperheating: on the basis of the first generation, the desuperheating water nozzle on the pipeline is moved to the upper or lower part of the decompression valve to make it a temperature reducing and pressure reducing valve and an orifice plate for throttling. Reduced pressure; eliminates the need for desuperheated water pipes in the first generation structure, which reduces floor space, reduces structure, facilitates installation and maintenance, reduces failures, avoids water hammer in the pipeline, increases the device's Service life. The disadvantage is that the temperature reducing and pressure reducing valve only adds the nozzle on the basis of the original pressure reducing valve, its internal structure form has not changed, and the temperature reducing system has not changed.
The third generation is the replacement product of the second generation: the inside of the temperature reducing and pressure reducing valve is replaced with a multi-stage sleeve type, which saves the orifice plate, and at the same time, the throttling orifice of the multi-stage sleeve also plays the role of silencing. Temperature reducing and pressure reducing valves and feed water regulating valves adopt the method of variable flow coefficient design of Siemens, Masoneilan and Fischer. The characteristic of this design is that the design and use are consistent. Since the feedwater regulating valve can be applied to various pressure differentials, the throttle valve or throttling device is eliminated in the desuperheating system. The third-generation products not only have all the advantages of the second-generation products, but also make up for all the shortcomings of the second-generation products: 1, decompression, and multi-level synchronous adjustment to improve the adjustment range; 2, the use of synchronous adjustable spray The nozzle sprays water in the valve to improve the atomization effect.
First-generation temperature-reducing and pressure-reducing device The second-generation temperature-reducing and pressure-reducing device The third-generation temperature-reducing and pressure-reducing device The temperature-reducing and pressure-reducing structure is a single-stage plunger structure. Narrow, only one level is adjustable; Because of the use of range selection, the adjustment performance is inaccurate. The advantages of a single-stage plunger structure The nozzle is mounted in the valve and the atomization effect is good. Disadvantages The noise is more likely to cause the vibration affect the life of the valve; the adjustment range is narrow, only one level can be adjusted; Because of the use of more range modeling, the adjustment performance is not accurate. The advantages of a multi-stage cage structure The nozzle is mounted in the valve and the atomization effect is good. The valve is adjustable in multiple stages; The adjustment range is 0-100% adjustable; Designed for the user's use of parameters, through the calculation of variables to ensure the accuracy of each level of regulation. At the same time cage structure can play a role in silencer. pipeline The disadvantages of the connection between the decompression piping and the desuperheating piping are that the piping is too lengthy, and the decompression piping adds a number of throttle orifices to compensate for the lack of pressure reducing valves. The mixed piping and the text piping in the desuperheating piping increase the cost, Increased weight, increased floor space, high failure rate, inconvenience to installation and maintenance. Eliminates the advantages of desuperheating pipes. Shortens the length of the main steam line; Reduces weight, reduces floor space, reduces breakdowns, and facilitates installation and maintenance. Disadvantages The addition of the orifice plate to the pipeline to compensate for the lack of temperature reducing valve; throttle plate can not be adjusted. The advantages of desuperheating pipelines have been eliminated. The multi-stage depressurization eliminates the orifice plates on the pipelines in the valve, thus greatly shortening the length of the main steam pipeline. Reduced weight, reduced floor space, reduced failures, ease of installation and maintenance. Throttle valve with the use of regulating valve, to adjust the valve with the pressure with the regulating valve, to the regulator valve pressure regulator valve can be used alone, no throttle valve or throttling device. Regulators are mostly single-stage constant-pressure differentials. Disadvantages The narrow range of adjustment, only one level is adjustable; due to multiple range selection, the adjustment performance is not accurate. Can not be applied to all kinds of pressure difference, there must be auxiliary equipment used together, generally can not be used alone. Most of the disadvantages of a single-stage constant pressure difference structure The narrow range of adjustment, only one level can be adjusted; Because of the use of multiple range selection, so the adjustment performance is not accurate. Can not be applied to all kinds of pressure difference, there must be auxiliary equipment used together, generally can not be used alone. Multi-level constant pressure difference structure advantages Multi-stage adjustable, accurate adjustment performance, variable design, suitable for various pressure differences, can be used alone. The nozzles are directly mounted on the main pipeline with adjustable or fixed structural defects. Poor atomization results in water flooding in the main pipeline, which can cause pipeline vibration and reduce the service life. As the water cooling in the pipeline must be There is a certain length of atomization section, which makes the main pipeline too lengthy. The advantages of the fixed structure installed in the valve improve the atomization effect, eliminating the atomization section, avoiding the water hammer phenomenon caused by the pipe water accumulation, and improving the service life of the device. Advantages of Direct Mounting into Valves with Fixed or Adjustable Structures Because multi-stage depressurization eliminates the need for orifice plates in the piping, the length of the main steam line is greatly reduced. Reduced weight, reduced floor space, reduced failures, ease of installation and maintenance