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    Matters needing attention in selecting driving devices for valves

    Column:Technology Frontier Time:2016-07-14

    When choosing the driving device of the valve, the following points should be noted:

    1. According to the use occasion and purpose of the valve, determine the driving mode: manual, electric, pneumatic, hydraulic.

    2. Selection of manual mode:

    The specifications of a ball valve and butterfly valve "DN150" can be driven by a handle, while the specifications "DN200" should be driven by a worm gear box.

    The specifications of the B gate valve "DN400" can be driven by handwheel; the specifications "DN450" should be driven by gearbox.

    C gate specifications "600X600 can choose handwheel hoist; specifications" 700X700 should choose gear box hoist.

    D Globe Valve Specification "DN150 can be driven by hand wheel".

    3. Electric mode selection:

    A. Firstly, the types of electric devices are determined: switching multi-gyration and switching partial gyration, adjusting multi-gyration, adjusting partial gyration, electric angle stroke actuator and electric direct stroke actuator.

    B. Switch type electrical equipment for all-open and full-closed shutoff valves. Switch type multi-turn electrical equipment is used for gate valve, knife gate valve and globe valve, and switch type partial rotary electrical equipment is used for butterfly valve and ball valve, but the drive mode of multi-turn electrical equipment + worm wheel box is used for butterfly valve specification DN800. Switch-type electrical equipment can output on-off and off signals, which can be centralized and controlled remotely. Switch type electrical installation generally has manual function.

    C. Regulating electrics is used for adjusting valves which need to continuously adjust medium flow. The opening and closing parts of electrically controlled valves can stay at any position in the process. Regulating multi-turn electrical equipment for knife gate valves and throttle valves; Regulating partial rotary electrical equipment for butterfly valves and ball valves; Electric angular stroke actuator for damper and flue butterfly valves; Electric direct stroke actuator for single and double seat regulating valves.

    The control modes of adjustable electrical installations are as follows:

    Proportional adjustable input analog control signal, closed-loop control, automatic adjustment;

    Once the remote control type input the continuous contact signal, the electric installation will continue to run; when the signal disappears and the electric installation stops running, the valve opening and closing parts can be controlled at any position, and the position feedback signal can be output, and the open-loop control can be realized.

    Various adjustable electrical installations are terminal actuators. Users are required to equip with control instrument system or computer control system.

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

    E. Electric valves should be carefully read the instructions before installation and wiring, and operate according to regulations.

    4. Pneumatic mode selection:

    A. Firstly, the types of pneumatic devices are determined: switching type and adjusting type.

    B. Determine the structure of pneumatic device: single-cylinder single-action, single-cylinder double-action, double-cylinder single-action, double-cylinder double-action.

    C. Gate valves, knife gate valves and globe valves are directly driven by air-mounted switching devices installed vertically in cylinders, which are generally used for opening and closing. Butterfly and ball valves use horizontal cylinder to drive fork or rack to drive hoist 90. The rotating part of the rotary gas holder can be used for opening and closing, or positioner can be installed to become an adjusting valve.

    D. Pneumatic devices are usually built-up modular designs, which can be assembled into switching and adjusting pneumatic assemblies of various performances according to working conditions.

    Commonly used modular components are: electromagnetic commutation valve, signal box, positioner, manual mechanism, pressure-retaining gas storage tank and gas source triple parts. Users can choose according to their working conditions.

    E. The normal operation of pneumatic valves requires a gas source pressure of 0.4 "0.6 MPa. Users'special requirements for gas source pressure should be specified in the contract.

    F. Pneumatic valves should be carefully read the instructions before installation and operation.

    5. Hydraulic mode selection:

    A. 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. Electro-hydraulic push rod is an electro-mechanical-hydraulic integrated device. The other hydraulic stations with various hydraulic modes can be designed and manufactured in an integrated way with driving cylinders and valves, or they can be manufactured separately from valves and installed separately. Users can choose according to the needs of the site.

    C. Sluice valve, gate, knife gate valve and globe valve can be driven by cylinder or hydraulic push rod; butterfly valve and ball valve should be driven by 90 degree rotary weight or accumulator, or by hydraulic push rod.

    D. Installation of hydraulic valves shall be in accordance with the requirements of the operation instructions, and commissioning shall be directed by the technical personnel of the manufacturer on site.