Intelligent electric control valve
I. Introduction:
To improve the economic efficiency of power plants, steam turbines are equipped with regenerative systems, which are installed with high-pressure and low-pressure heaters. To ensure that the heaters operate with water level, and prevent the steam from the previous stage of the steam turbine from leaking into the next stage when the heater operates without water level, which would reduce the efficiency of the steam turbine and the safety of equipment, a drain control valve is installed in the drain system of the heater. It automatically adjusts the opening of the drain control valve based on the water level signal of the heater, so that the water level of the heater is always maintained within a certain range. The working conditions of the drain control valve are very harsh. In many cases, it works under two-phase fluid (i.e., steam-water mixture), and also operates in a throttling state, resulting in severe cavitation. When cavitation reaches a certain level, the drain control valve can no longer function properly. Under such circumstances, the heater cannot be guaranteed to operate with water level, which reduces the economic efficiency of the steam turbine. Therefore, it is particularly important to select a drain control valve with small cavitation, low noise, simple structure and reliable performance.
II. Part Materials:
Valve body, valve cover: HT200, ZG230-450, ZG1Cr18Ni9Ti
Valve core, valve seat: 1Cr18Ni9Ti, Stellite alloy hardfacing
Valve stem, push rod: 2Cr13, 1Cr18Ni9Ti
Bushing: 2Cr13
Gland packing: Polytetrafluoroethylene (PTFE), flexible graphite, stainless steel bellows
III. Technical Parameters:
Nominal diameter DN (mm) |
20 |
25 |
32 |
40 |
50 |
65 |
80 |
100 |
125 |
150 |
200 |
250 |
300 |
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(10) |
(12) |
(15) |
(20) |
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Rated flow coefficient Kv |
Linear |
1.8 |
2.8 |
4.4 |
6.9 |
11 |
17.6 |
27.5 |
44 |
69 |
110 |
176 |
275 |
440 |
690 |
1100 |
1760 |
Equal percentage |
1.6 |
2.5 |
4.0 |
6.3 |
10 |
16 |
25 |
40 |
63 |
100 |
160 |
250 |
400 |
630 |
1000 |
1600 |
|
Rated stroke L (mm) |
10 |
16 |
25 |
40 |
60 |
100 |
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Intrinsic flow characteristic |
Linear, equal percentage |
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Intrinsic rangeability R |
50:1 |
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Allowable leakage |
Hard valve seat: Class IV, soft valve seat: Class VI |
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Nominal pressure PN (MPa) |
1.6, 4.0, 6.4 |
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Working temperature t (℃) |
Normal temperature type |
-20～200, -40～250, -60～250 |
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Heat-dissipation type |
-40～450, -60～450 |
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High temperature type |
450～560 |
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Low temperature type |
-60～-100, -100～-200, -200～-250 |
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| Machinery & Equipment/Valves/Control Valves | |
