I don't know the principle of operation of the butterfly valve. Can I control the percentage of opening by an analog output from the PLC?
A okorder /... All of the control valves I have installed have been electric and used a 4-20ma to control the position of the valve. I used a Watlow controller to produce the 4-20ma. I use it to control the flow of chilled water for a process. I would contact tyco and tell them you are checking into prices and what it would take to run a 2 butterfly valve to control chilled water. I want it to be ran by an analog output from a PLC. They will be able to give you the information that you need. I hope this helps, Good Luck
Edit: the fast literal answer is no with the aid of be conscious in basic terms. each sort of valve may well be usually considered to be a pass administration device. maximum styles of valves, gate, globe, ball, B'fy may well be manually set everywhere from finished open to totally closed and can be set to any in part open place. The term administration valve usually refers to valves, which comprise butterfly types that are immediately regulated to modulate a cost of pass in accordance to a administration sign to the valve actuating device. in specific circumstances the sign is from a distant sensing element such with the aid of fact the temperature sensor controlling a refrigeration expansion valve. sometime the sign is from in the actuating device itself as in a water rigidity regulator on your place city water grant. The sign itself may well be modulating , as above or that's on/off which includes an emergency shutdown valve on a steam turbine or the on/off valve on your washer.
You can purchase operators for some butterfly valves for either on/off operations or to modulate but the flow characteristics of a butterfly valve makes is a very poor modulating control valve,
A butterfly valve does not have an overall linear characteristic and is a poor modulation controller through its full range of operation. It will need a stout shaft and a tough actuator. It will be most linear in about the 30% to 60% open range. To make a full linear controller, you will need to have the actuator-controller- valve , single source supplier know what control feature you wish to accomplish in the fluid system and what the controlling signal will be. Any cotrol valve is a variable resistance added in the whole dynamic system which itself will have an inherent second order friction loss flow characteristic.
