Notes for Selecting Drive Devices for Valves

Notes for Selecting Drive Devices for Valves

Here are the notes for selecting drive devices for valves.

When selecting the driving device for the valve, the following precautions should be taken.

1. Determine the driving mode based on the valve's usage and purpose: manual, electric, pneumatic, and hydraulic.

2. Manual mode selection:
When the specifications for ball valves and butterfly valves are DN150, the handle drive can be selected. When the specifications are DN200, a worm gearbox drive should be selected. The specification of the gate valve "DN400 can choose hand-wheel drive. The specification" DN450 should choose gearbox drive. The specification of the gate is "600X600" which can choose a hand-wheel hoist. The specification "700X700" should choose a gearbox hoist. The specifications of the shut-off valve can be selected as a hand-wheel drive for DN150.

3. Selection of electric mode:

a. First, determine the type of electric device: switch type multi-rotating electrical device, switch type partial rotating electrical device. Adjustable multi-turn electrical equipment, adjustable partial turn electrical equipment, electric angle stroke actuator, and electric straight stroke actuator.

b. Switch-type electrical installation is used for fully open and fully closed shut-off valves. Switch-type multi-turn electrical equipment for gate valves, knife gate valves, and globe valves. The butterfly valve and ball valve adopt switch-type partial rotary electric installation. However, when the butterfly valve specification is DN800, the drive method of multi-rotary electric installation and worm gearbox is adopted. The switch-type electrical device outputs on/off electrical signals and can be remotely and centrally controlled. Switch-type electrical installations generally have manual functions.

c. The adjustable electric valve is used for regulating valves that require continuous adjustment of medium flow. The opening and closing parts of the electric control valve can stay at any position of the stroke. Adjustable multi-turn electrical equipment for knife gate and throttle valves. Butterfly valves and ball valves are equipped with adjustable partial rotary electrical fittings. The damper and flue butterfly valve adopt electric angle stroke actuators. Electric straight-stroke actuators are used for single and double-seat regulating valves.

The control methods for adjustable electrical fixtures include:
Proportional adjustment type - input analog control signal, closed-loop control, automatic adjustment.

The remote control type continuously operates when a continuous contact signal is input. When the signal disappears and the electrical device stops running, the valve opening and closing components can be controlled at any position, and a position feedback signal can be output for open loop control.

Various adjustable electrical devices are terminal actuators that require users to be equipped with control instrument systems or computer control systems.

d. When ordering electric valves, users should pay attention to whether the power parameters, installation method, output torque, stroke, control signal, protection level, explosion-proof level, and other performance meet their requirements.

e. Before installing and wiring electric valves, carefully read the user manual and operate according to regulations.

4. Pneumatic mode selection:

a. Firstly, determine the type of pneumatic device: switch type pneumatic device and regulating type pneumatic device.

b. Determine the structure of the pneumatic device: single cylinder single acting, single cylinder double acting, double cylinder single acting, double cylinder double acting.

c. Gate valves, knife gate valves, and globe valves use a switch-type pneumatic device installed vertically with a cylinder to directly drive the opening and closing components, which is generally used for opening and closing. The butterfly valve and ball valve use a horizontal cylinder to push the fork or rack to drive the opening and closing parts. The rotating part of the rotary valve can be used for opening and closing, or a positioner can be added to become a regulating valve.

d. Pneumatic devices are usually designed with modular building blocks, which can be assembled into various performance switches and adjustment pneumatic devices according to the working conditions.

The commonly used modular components include an electromagnetic directional valve, signal box, locator, manual mechanism, pressure-maintaining gas storage tank, and air source triplet, etc. Users can choose according to the working conditions.

e. The normal operation of pneumatic valves requires an air source pressure of 0 4 "0 6MPa. If users have special requirements for the air source pressure, it should be noted in the contract.
f. Before installing and using pneumatic valves, carefully read the user manual and operate according to regulations.

5. Selection of hydraulic mode:

a. The hydraulic modes include cylinder direct stroke drive type, 90-degree rotary hammer type, 90-degree rotary accumulator type, and electro-hydraulic push rod type.

b. The electro-hydraulic push rod is an electromechanical hydraulic integrated device and other hydraulic stations with various hydraulic modes can be designed and manufactured with integrated drive cylinders and valves. The hydraulic station and valves can also be manufactured separately and installed separately. Users can choose according to on-site needs.

c. Gate valves, gates, knife gate valves, and globe valves can be selected from the cylinder direct stroke drive type or the electro-hydraulic push rod type; Butterfly valves and ball valves should be of the 90-degree rotary hammer type or accumulator type, and can also be driven by an electro-hydraulic push rod.

d. The installation of hydraulic valves should follow the requirements of the user manual, and the debugging should be guided by the manufacturer's technical personnel on site.