VAG PICO Diaphragm Valve for automatic and simple water regulation

Transcription

1 VAG PICO Diaphragm Valve for automatic and simple water regulation

2 VAG PICO Diaphragm Valves VAG PICO Diaphragm Valves consists of a hydraulically operated main valve and a pilot circuit. The main valve is the basis for all control valve types and consists of three main parts: body cover diaphragm assembly The valve can control a range of applications simply by changing the pilot circuit. These includes pressure reduction & sustaining, level control, pressure relief and many more functions. In most cases functions can be added at a later stage without removing the valve from the line. This opens a wide range of possibilities. The only moving parts in the main valve is the diaphragm assembly, which are guided by an exchangeable bearing in the cover and the valve seat. The diaphragm, a resilient synthetic rubber, which is clamped in between body and cover, separates the control pressure from the line pressure. Extensive research and development looking at the ratio between the surface areas of the diaphragm and the seal ensures that the valve assembly will close if the pressure in the cover chamber and the inlet chamber are the same. The seal on the diaphragm assembly attached at the valve seat guarantees a perfect and long lasting seal, allowing the control valve to act as a leak tight on/off valve at the same time. The pilot circuit is equipped with a high capacity strainer, which ensures that the pilot valve will not become blocked. The valve needs no lubrication, has a simple design and therefore requires little maintenance. Also a long service life is assured. Any work that is required can be done with the valve in position and therefore maintenance can be undertaken on site. Due to this fact down times are minimized. Mode of Operation The sectional drawings below shows a main valve equipped with a simple on/off control pilot, mounted in the control tubing connected to the outlet side, and a restriction or needle valve on the inlet side of the valve. The pilot valve can perform three tasks: open close control ) ( ) ( ) ( Note In all situations the main valve follows the movements of the control pilot ) ( = restriction flow flow flow Basic valve closed Basic valve open Basic valve regulates Basic valve closed The control pilot does not drain liquid. The medium is being transported in through the inlet side: the main valve closes progressively. Basic valve open The control pilot drains more medium than is being added through the restriction: the main valve opens progressively. Basic valve controls When a balance between supply and drain of medium is reached then the main valve is hydraulically placed in the correct position.

3 VAG PICO Main Valve Features and design of the main valve For all types of the VAG PICO Diaphragm Valve, the main valve forms the basis of the various models and functionalities. Due to this, only one single main valve is needed for the combination of different valve functions and the valve can be equipped according to your specific, individual requirements. This versatile valve design provides a lot of benefits to our customers: Minimum friction coefficients The diaphragm-actuated motion rod allows low-friction motion with very low hysteresis. Low maintenance expenditure Only one moving interior part ensures reliable function and requires little maintenance. Epoxy coating All cast parts are epoxy-powder coated on the inside and outside. VAG PICO Main Valve Bonnet Spring Position indicator with venting screw Bearing bush Hexagonal screw Stem nut Diaphragm retaining disk Diaphragm Retaining ring Sealing ring Seat ring Body Stem

4 VAG PICO Control Circuit Features and design of the control circuit The components of the control circuit assembled to the main valve implement the functions of the diaphragm valve. The stainless-steel pilot valve works according to the 'balanced pressure principle', which means that changes of the system pressure do not affect the adjusted set-point value. The filter installed in the control circuit is a high-capacity filter which can be purged and is equipped with an inspection glass. The integrated control unit allows the separate adjustment of the opening and closing speed. VAG PICO with control circuit Stainless-steel casing control unit for the separate adjustment of the reaction velocity for Close and Open Stainless steel pilot valve body Stainless steel throttling orifice Manometer for easier commissioning Stainless steel filter casing Piping and screw connections made of stainless steel Stop valve for manual purging High-capacity filter equipped with an inspection glass for easy identification of the degree of soiling. Size of filtering surface 50 cm² min., perforation 0.5 mm max. VAG PICO Pilot Valve Plastic bonnet VAG PICO Control Unit For separate adjustment of the opening and closing speed Stainless steel body Closing speed (CS) Stainless steel body Opening speed (OS)

5 Pressure Control Pressure reducing valve type 02 Pressure Reducing Valve reduces a higher upstream pressure to a constant lower downstream pressure. The standard pressure range is: On request: 2-12 bar 0,4-2 bar 1-5,5 bar 5-21 bar Pressure reducing valve with bypass type 02 (LF) This pressure reducing valve is additionally equipped with a bypass for low volume control. Pressure sustaining valve type 03 (S) Pressure sustaining/relief valves opens when the preset inlet pressure is achieved. The standard pressure range is: On request: 3-21 bar 0,1-6 bar Pressure reducing / sustaining valve type (S) Pressure sustaining and relief valve which reduces a higher inlet pressure to a constant lower outlet pressure. The valve closes, however, to retain the inlet pressure in case the supply pressure drops below a predetermined value. Pressure reducing function: On request: Pressure sustaining function: On request: 2-12 bar 0,4-2 bar 1-5,5 bar 5-21 bar 3-21 bar 0,1-6 bar

6 Level Control Float valve type 04 (N) Float valve used to maintain a constant level. The control valve is installed in the water tank on site and connected to the main valve by a pipeline. Opening and closing speeds can be adjusted. (The DN10 pipeline installed between the main valve and control unit is not included in the scope of supply.) Float valve type 04 (DI) Float valve with adjustable minimum/maximum level. The main valve opens when the minimum level is reached and closes when the maximum level is reached. The difference between the minimum and maximum level corresponds to the length of the pipeline between the two floats. Adjustable opening and closing speed. (The pipeline installed between the main valve and control unit is not included in the scope of supply.) Level control valve type 05 (A) Control valve used to maintain a constant (adjustable) water level. If the water is drained from the reservoir, the pressure in the diaphragm chamber is lowered and the main valve opens. Standard range: mws Upon request mws Adjustable opening and closing speed. (Pipeline from main valve to reservoir needs to be installed on site.) Flow Control Flow control valve type 06 (OC) Flow control valve used to limit the flow to an adjustable maximum irrespective of the inlet pressure.

7 Specifications Application areas and limits Differential pressure: Minimum differential pressure: 0.5 bar (lower differential pressure upon request) Maximum differential pressure: according to cavitation diagram Flow velocity: Maximum flow velocity in continuous operation: 4,5 m/s Maximum flow velocity for short-time operation: 5,6 m/s Recommended flow velocity 2-3 m/s Cavitation curve when the valve is open Upstream pressure [bar] B A C Downstream pressure [bar] AA: No cavitation: The standard valve can be used. B: Cavitation area: IIn this area two serially mounted valves are to be used or a valve with a special orifice cylinder. Please consult the manufacturer on this issue C: Transitional area: Please contact the manufacturer for information about this area. Flow characteristics [m³/h]: Nominal diameter Q-min 0,7 0,8 1,6 2,7 4,4 5,3 13, Q-max Continuous operation Q-max Short-time operation If in the application of a pressure reducing valve, volumes are to be below the minimum volumes, a bypass with an additional pilot valve is to be used.

8 Edition 3-06/08 VAG PICO Diaphragm Valve Installation recommendations The automatic control valves should be installed between two shut-off valves and strainer in a horizontal pipeline. A bypass allows the maintenance of the control valve during operation. For the protection of the supply network, we recommend the installation of safety valves Main line (Basic components) VAG PICO Diaphragm Valve VAG Strainer VAG DUOJET Air Valve 4 VAG EKOplus Gate Valve 5 VAG FLEXINOX (Dismantling Piece) 6 Bypass line (horizontal in general and at the same level as the main line) 10 VAG PICO Diaphragm Valve 11 VAG Strainer 12 VAG FLEXINOX (Dismantling Piece) 13 VAG EKOplus Gate Valve Discharge / safety valve VAG-Armaturen GmbH Carl-Reuther-Str Mannheim Germany Phone Fax info@vag-armaturen.com