Motor Operated Valves and Flow Control Valves

<...difference in Motor operated valve & Flow control valve...>

They are two different things for two different functions. The difference is self-evident from their names.

<....End connections reqd, Function.....Flow rate that can be handled, etc....>

These should be tabulated in the Valve Schedule, will be project-specific, and will depend largely upon the piping standard called for.

<...Which is the best one flow meter....>

Instrument suppliers make all different kinds of flowmeters. What is the application?

Valves can be controlled (actuated) by many means. a Motor Controlled Valve is controlled (actuated) by a motor.

Like PW says, it's in the name. But the name doesn't say what type of valve it is. It could simply be a butterfly, ball, gate valve, etc - which isn't desgined for accurate contol of flow or pressure. Or else is could be a diapham or globe valve, that are better suited to flow/pressure control.

The Flow Control Valve is suited to controlling flow, but the name doesn't describe it's method of control, it may be actuated by a Motor (as the previous vavle), or Air, or even manually controlled.

End connections can vary between manufacturers, or possibly as opions from a single manufacturer.

For controlling flow, I suggest you use a globe type valve. these can be automatically controlled using an Air diaphram controller. These are not cheap valves, but a well designed valve will pay for itself in efficiencies and cost savings.

Kind Regards,

Anthony

Hi, my friend

You're mixing too much concepts in a single post!

A valve can be classified according to many aspects: Size, pressure/temperature rating, stem type (rising, rising and rotating, quarter turn...), disc type (gate, globe, diaphragm, butterfly, plug, ball, needle....), actuator (manual, self actuated, motor operated/MOV, pneumatic/AOV, hydraulic, solenoid...) and many others.

One thing is the valve and another different the actuation type or service mode.

MOVs mostly are used for on-off service, while fluid operators are better suited for flow control. However there exist motor operators for modulating service and even I've installed what I think were the first solenoid modulating valves.

The same is regarding disc type: Gate valves aren't adequate for flow control while globe, needle... are better for this type of service.

Connecting ends are usually not dependent of actuation type. It's a function of valve size, service, design Code requirements/limitations...

Flow rate that can be handled is mainly a function of valve ND (Piping NPS). You can find for example a 4" valve in any service type, geometry, actuation type, etc.

If you make a more specific question we could give you a more specific answer.

Best regards

Is this a trick question ??

hi sachin

let me tell u that this valves MOV'S, MCV'S & FCV'S are having different application,

MOV'S are use for on -off application and usually installed at remote areas, the end connections are generally same with the standardised valves may be a gate valve or a ball valve , MOV'S have 2 torque limit switch and the motor rotates clockwise and anticlockwise direction between this switches depending on which switch is actuated . there are two switches given for indication for valve fully close and fully open , it has 3 commands open ,stop and close , it operate on 1phase or 3phase supply ac voltage as optional, and it may take 15 sec to 1min to have max travel , cost of MOV'S is more as compare with pneumatic on-off valves ,and the end connection are standardise with standard gate valve and ball valve end connections.

http://www.rotork.com/en/document/index/

MCV'S are motorised control valves this are generally used for steam and water service .

Flow control valves are only to control the flow of fluid in a pipe line . Generally they are control valves can fit to control any parameters as per the application this valves are designed as per flow max required ,line size ,fluid properties and get the value called Cv to suit the application. this control valve operates for the control signal 4 to 20 ma, it can handle the flow rate what is designed and calculated for particular application .the end connection are standardise with standard globe valve end connections

what type of flow meter you know and for which application u need so that it will be easy to give best one ?

for more information

http://www.engineeringtoolbox.com/control-valves-t_45.html

hope u get the suitable information

regards

Adil

Thanks Adil for this info.

Could you please tell me whether MOV can be considered as control valve or not

Regards

Sachin

hi sachin

No way ,so far I have seen are used for on -off application e.g for loading of ship tankers is one of our application where we are using it .

secondly they are slow in operation as campare to control valve and motorised actuators can be retro fit on a maechanical on-off valve . but control valve is completely designed for that particular application actuator to trimsize ,valve size etc

regards

Adil

MOV and control valve are two different concepts.

MOV is a valve class regarding the actuation type (motor operator)

Control Valve is a class regarding its function in a system (modulate flow, pressure...)

A MOV can be a control valve if its function is to modulate ( Look for example Auma multiturn motor actuators, series "SAR") even most of MOV have on-off function.

http://www.auma.com/cms/AUMA/en/products/multiturnActuators/1,111003,23734.html

Kind regards

what I feel they are modulating actuators but I search in spec sheet but I checked the full travel time sec min travel 20mm is 60 sec well they are slow compare to pneumatic control valve is less than 3sec for 20mm so it can be use for modulating but not on critical system . adil

what I feel they are modulating actuators but I search in spec sheet but I checked the full travel time for 20mm is 60 sec well they are slow compare to pneumatic control valve which is less than 3sec for 20mm so it can be use for modulating but not on critical system . adil

Hello,

Please see http://www.auma.com/uploads/media/sp_import2/technische_daten/antriebe/drehantriebe/drehstrom/td_sar1_3ph_en.pdf

you can see that maximum output speed for 50Hz are 45 rpm. (for 60 Hz are 54 rpm). Given the actuator speed, the stem speed is the stem thread lead times the actuator speed.

For example: 45 rpm = 0,75 rps.

Assuming a 1/4" pitch and lead (very common for small-medium size valves), the stem will travel (1/4) (0,75) = 0,1875 inches/sec = 4,7625 mm/sec. This stem speed means a 20mm stroke valve an actuation time of 4,2 sec. With the same pitch ant twice lead, the stoke time will be half (2,1 sec).

60 sec for a 20 mm stroke is a very slow speed even for a motor operator.

Anyway, a control valve is used to modulate flow , and a different valve is normally used for on-off service. Single acting pneumatic valves have a fail safe function (open or closed) and the action is performed by a spring, usually fast but with an uncontrolled stroke speed.

Kind regards

I have actually measured for MOV's they are more slower than control valve ,also for high volume actuator, time can be improved by putting exhaust valve , but MOV's dóes not have this facility what ever travel time is there is there can't improve . but are very good for hi torque application. where pneumatic valve may stuck or can give jerky movement .

modulating valve do have 4.5 sec travel time but still more than the controlvalve travel time for 26mm of travel

That's the difference.

MOV's can have a wide range of speed, but once selected the actuator, the speed is nearly constant. Pneumatic ones can act faster if you want they run a full stroke.

Of course, the main function of control valves isn't to isolate flow and therefore for the same system conditions, control valves need less thrust/torque applied to the valve stem/shaft.

Isolation valves which need to operate under high flow/DP conditions need much more thrust/torque and hence the motor operator is more adequate.

Kind regards