Reliable fixing of shaft
The anti-blow-out structure is provided at the top of the shaft to prevent theshaft from running out of the gland in case of accidental breaking of the shaft.
Convenient seat maintenance and servicing
The seat can be replaced just through removing the inserts without theneed of disassembling the butterfly valve and shaft.
Provided with shut-off and control functions
- Having excellent control characteristics
- Proportional change of flow characteristic curve
- Wide adjusting range
- Tight sealing can be realized even when it is used for control.
Rated value
Seat rated value
The seat rated values indicated on the curve are only for the seat, t is thediferential pressure between the two ends otthe butterfly valve when the valveis fully closed. These rated values can serve as use quide under generalconditions. According to past experience, the rated values for improved andchanged other eat materials may be higher.
Body rated value
The maximum working pressure of body and testing pressure of body ofvarious materials are listed in the body pressure ratings table. The actuaworking pressure in the working conditions shall be decided according tothe seat rated values.
The flow coefficient of 150lb and 300lb butterfly valves is listed in the followingtable. Cv value indicates water flow per minute that passes through the fullyopened valve when the differential pressure is 1psi (0.07bar) and thetemperature is 60°F(15.6C ), and its unit is USqal/min.
To confirm Cv value of the valve at the middle position:
1. Confirm the percentage of the maximum Cv value from the curve
2. Multiply the percentage of the maximum Cv value from the curve by the Cvvalue from the flow datasheet
For example: The Cv value of the butterfly valve of 6"(DN150), 150lb underopening of 70% is:(1) Confirm the percentage of the maximum Cv value of the butterfly valve of6"(DN150), 150lb under opening of 70% is 53%.(2) The maximum Cv value is: Cv value=0.53 X 1050=560
Table of materials for spare parts
