Relief Valves
RELIEF VALVE DIMENSIONS
Regenerative Turbine Pumps should never be operated at no-flow, or “shut-off” conditions. In systems where pumps may exceed the pump or system design operating pressure, it is highly recommended that a Pressure Relief Valve or other protective device be installed in the discharge line. This will relieve excess pressure and prevent motor overload or pump failure in the event of restricted flow conditions. Another more sophisticated option is to use a VFD (variable frequency drive) with a closed-loop pressure transducer feedback loop. This equipment will allow the automatic adjustment and limiting of motor RPM to maintain a given pressure. MTH provides both relief valves and VFD’s for use with its pumps, as optional purchased accessories.
VALVE SIZE |
AA |
BB |
CC |
INLET SIZE |
OUTLET SIZE |
1/2" |
5 13/16 |
2 1/8 |
1 9/32 |
1/2" |
3/4" |
3/4" |
5 15/16 |
2 5/16 |
1 13/32 |
3/4" |
1" |
1" |
6 31/32 |
2 27/32 |
1 3/4 |
1" |
1 1/4" |
1 1/4” |
8 5/16 |
3 1/2 |
2 |
1 1/4" |
1 1/2” |
1 1/2” |
9 1/2 |
3 5/8 |
2 3/16 |
1 1/2” |
2” |
Relief Valve Sizing
- Add 10 PSI (23') to customer specified operating head and locate on pump curve. Log capacity and BHP from this point. Check to be sure motor horsepower is large enough to handle this head.
- Convert head to PSI and add to pump suction pressure to determine PRV setting.
- Go to PRV flow/pressure chart to select size of valve necessary.
Series 78-79 Brass Valves
Water Capacity in Gallons per minute (GPM) at 25% Over Pressure
SET PRESSURE |
SEAT SIZE - Inches | |||||||
1/2 | 3/4 | 1 | 1 1/4 | 1 1/2 | 2 | 2 1/2 | 3 | |
5 | 2.8 | 3.9 | 7.7 | 12 | 17 | 22 | 33 | 44 |
10 | 3.9 | 5.6 | 8.1 | 17 | 24 | 31 | 46 | 62 |
15 | 4.8 | 6.8 | 13 | 21 | 29 | 38 | 56 | 76 |
20 | 5.5 | 7.9 | 15 | 24 | 34 | 44 | 65 | 88 |
25 | 6.2 | 8.8 | 17 | 27 | 38 | 49 | 73 | 98 |
30 | 6.8 | 9.7 | 19 | 29 | 41 | 53 | 80 | 107 |
40 | 7.7 | 11 | 22 | 34 | 48 | 62 | 92 | 124 |
50 | 8.4 | 12 | 24 | 38 | 53 | 69 | 103 | 139 |
75 | 10.5 | 15 | 30 | 47 | 65 | 85 | 126 | 170 |
100 | 12 | 18 | 34 | 54 | 76 | 98 | 146 | 196 |
110 | 13.3 | 19 | 36 | 56 | 79 | 102 | 153 | 206 |
125 | 14 | 20 | 38 | 60 | 85 | 109 | 163 | 219 |
150 | 15.4 | 22 | 42 | 66 | 93 | 120 | 178 | 240 |
175 | 16.1 | 23 | 45 | 71 | 100 | 129 | 193 | 259 |
200 | 17.5 | 25 | 48 | 76 | 107 | 138 | 206 | 277 |
250 | 19.6 | 28 | 54 | 85 | 120 | 154 | 230 | 310 |
300 | 21.7 | 31 | 59 | 93 | 131 | 169 | 252 | 340 |