Operation of Triple Offset Butterfly Valve
Generally operation type of triple offse butterfly valve include manual type(lever and gearbox type), pneumatic actuator type, electric actuator type, hydraustatic actuator type etc. Here we talk about manual type, how to choose lever and gearbox type operation ?
Gearbox operation is kind of merchanic way to open and close valve, the gear transmission valve utilizes gears of two gears to mesh with each other to transmit mechanical power and mechanical transmission. The valve device uses direct and passive transmission of gears and power from the main and driven gears.
Gearbox butterfly valve is more labor-saving than lever operation butterfly valve. So it should choose gearbox for larger diameter and higher pressure valve. Take API triple offset butterfly valve as example: ANSI 150# butterfly valve, 2’’ ~ 6’’ valve can be lever operation, it should be gearbox operation for butterfly valve 8’’ and larger size valve.
The other factor to use gearbox or not is installation situation.
It needs bigger space to use gearbox triple offse butterfly valve for it’s gearbox, handwheel etc., comparing lever butterfly valve. Sometime due to limitation of installation space, there is not enough space in certical direction for gearbox valve, it has to choose lever opertion. It does not matter if valve is small, such as diameter less than 8’’ ; but if valve is large diameter, normal lever can have enough input torque to open and close valve, and it needs lengthen lever, for example, the lever length should be about 1meter.
Zhejiang Zhengfeng Valve