Type LH45-16 flow Restriction check valve
Brief introduction:
Type LH45-16 series of flow restriction check valve is mainly used for parallel-connected pumps. It is installed at the outlet of the pump to restrict the working flux and prevent the reflux that may occur when the pumps stop working. Installed with guide valve, the main valve appears compact in structure and light in weight.

The product has been listed in the national major products and it was granted another name called the Automatic Controller of Self-operated Pump Lift.
Function and main operational principle:
Flow Restriction
Installed at the outlet of the pump, it is used to restrict the working flux of pump to ensure that it works at much higher efficiency, when single pump is started or part of the designed pumps are operated. It is also used to prevent the over loading and damage of motor due to excess rated current and hence achieve an effect of energy economization when the pump is working under low lift, big flux and low efficiency.
The principle for flow restriction is as follows:
With reference to the designed regime lift of the pump, the guide valve will automatically detect and control the actual pump lift to restrict the working flux of pump and the load of motor.
When a controlled working lift is set to the check valve, it will shut and make the actual working lift larger when the working lift of pump is lower than the controlled lift of check valve. On the contrary, the check valve will fully open and appears little resistance when the working lift of pump is larger than the designed lift.
The controlled lift can be set according to the motors rated current or high-efficiency regime. The working lift of the check valve is adjustable and normally the set value is the designed regime lift when check valve leaves factory.
Reflux Prevention
This valve performs exactly the same with that of slight resistance, retard shut check valve in terms of reflux prevention. It causes no closure noise and no reflux.
Technical Parameters
DN
Face to face length (L)
Max working flux
H1
H
Local resistance coefficient

50
230
25
140
220


65
290
50
160
255


80
310
70
170
267


100
350
100
195
302
46

125
400
150
268
400
46

150
480
250
297
450
46

200
495
400
340
523
36

250
622
800
423
635
36

300
750
1200
575
820
25

350
787
1400
585
860
25

400
978
1800
630
935
24

450
978
2400
695
1030
24

500
1016
3000
575
1025
24

600
1295
4000
872
1310
24

700
1448
6000
952
1407
24

800
1956
7500
1050
1560
24