Fast Way To Open/close A Butterfly Valve

[fastline]

We need to open and close a valve in .1sec and be able to vary the opening easily and precisely for flowing water. We are looking for possibly a type of servo motor in which we can just vary the voltage to it to get the desired position. This would need to be a small motor. We only need around 5 ft/lbs of torque max. Just thought some of these RC servos might be similar in design and seem to be rather quick.


We do not require RC operation and would prefer to hard wire but unsure what type of motor we are looking for. We would not really require an encoder to "really" precisely set position. that would probably be an overkill for this application.

 

[Nigel Goodwin]

If this is for a 'dancing water' display, I woudl suggest solenoid valves instead.

 

[fastline]

Not for dancing water but wondering if a solenoid valve can be setup for variable flow control with a pwm controller? Just not sure if one has to be specifically designed for this or what.


In my experience with irrigation type solenoid valves, they can present problems if they have too much down the line restriction and will refuse to open. IAT, a 1in valve has to flow a min of 5pgm to even open. This may not be the same with all valves but we figured it might be smart to jump over this potential problem and use a butterfly.

Did you feel the butterfly would be difficult to control quickly?

 

[user_88]

The 0.1 sec closure requirement is severely restrictive, as well as the position control without encoder.

Can you divulge anymore details of your project ..... what you are trying to accomplish?

 

[fastline]

Application get a bit complicated but basically, we need to have complete flow control over 30-50psi of water with gpm of 0-50. .1sec is a loose spec but offers relativity to our required speed control. We would rarely need full open to close but rather throttle between flow rates quickly. Example is to adjust from 42* to 43* very quickly.

We will need to build automation in so electrical control will be required.

The ideas on the table are to try and use a direct acting solenoid valve and PWM control the solenoid but I am concerned it will wear out the valve seat or solenoid very quickly as well as create a pulsating flow of water at lower modulated frequencies.

Another is to use PWM to modulate an air source to eith a butterfly or poppet style valve. The poppet is not as common but flow rate to opening would be more linear. The butterfly would give the least restriction, are common enough, would be easy to adapt for am air cylinder, but would be far from linear in response of flow vs opening.

Certainly open to other ideas but it seems most all valves in the industry that are auto controlled, are much slower than we need and way too costly.

 

[shingadaddy]

So you are
1. Using 30 - 50 PSI pressure presumably from a standard utility water supply system
2. You want 0-50 and 50-0 GPM flow rate adjustability in .1seconds
3. You want to control FLOW "precisely" in the range of 42 to 43 GPM.
4. 5 FOOT/POUNDS of torque..

You're going to have to monitor flow and/or pressure and or valve position to do any of this with any accuracy. And 5 ft/lb's of torque from a "SMALL" motor is going to take some doing. Probably requiring a gearhead (gear-reduction box).
Seems like your asking for champagne on a beer budget...You're right about needing SERVO type control which will require feedback from some parameter in the loop, whether it be pressure, flow or valve position and probably a combination if you don't monitor FLOW directly. High speed rotary valving can provide the accuracy but the speed is going to depend on how powerfull the motor choice is.

Are you talking 1 channel here or multiple channels?

 

[user_88]

Suggestion ...

A gate valve is a sliding gate that is used to regulate the fluid flow rate / pressure.

If you were to disassemble a standard gate valve, it might be possible to convert the standard thread/screw adjustment mechanism into a sliding version. That is, you would have a length of rod, exterior to the valve body, that could be manipulated in accordance to the position of the slide within the valve body. The remaining step would be devise a method of moving the valve rod in accordance with your input command.

It may be possible to machine a length of linear spur gears onto the rod, in the manner of a rack and pinion assembly. Another possibility is to weld a pre-fabricated length of rack onto the valve rod ..... Then you would attach a mating spur gear to a stepper motor .... programmed with your flow conditions or instructions.

The sliding gate valves are probably manufactured someplace, but would most likely demand an exorbitant price. If you could improvise your own version, it would be more economical.

.... Regarding the PWM of a solenoid valve .... this does not seem reasonable.
The few solenoids that I have seen are strictly on/off ..... like there is a sharp threshold between the open or shut position.

 

[fastline]

We are kind of bouncing around between ideas here for flow control. The pressure will be set with another regulator in the circuit. We have now considered PWM controlling a direct acting solenoid valve but concerned of quick failure from the open/close rates as well as the pulsed water that will come from the valve at lower modulated frequencies. We are advised by OEMs that this will work though, the PWM control anyway.

Also looking at using an air cylinder to control either a poppet or butterfly style valve so power can be utilized in shop air. closed loop operation is not needed but good control of the flow is because it will commanded by other circuits based on its flow performance down the line.

I am finding out that possibly putting a servo motor on will prove a costly process unless we can find a very basic stepper type motor for this and even then, that might prove an over kill. I am envisioning varying a voltage via PWM to either a direct mounted motor or an air solenoid so I can vary the flow rate of the valve.


All other ideas considered at this point. The over all goal here is simplicity. We were reaching at the butterfly and poppet because they can be easily modified for another (our) application.

 

[shingadaddy]

"I am finding out that possibly putting a servo motor on will prove a costly process unless we can find a very basic stepper type motor for this and even then, that might prove an over kill."

Do you mean COST overkill?

"I am envisioning varying a voltage via PWM to either a direct mounted motor or an air solenoid so I can vary the flow rate of the valve."

Is it safe to assume you are using a computer somewhere to do the control or are you building up some sort of circuitry to do the control?

Air solenoid? PWM? Are you saying you're going to attempt flow control by similar means as a fuel injector, by varying the on(OPEN) - off(CLOSED) duty cycle of some spring loaded CLOSED valve arangment?

Just trying to get an accurate picture in my head here..

 

[fastline]

Yes, a direct acting solenoid valve will raise a needle to allow flow. My reaction is the same as yours on that but a couple OEMs tell me it can work. I am hesitant.

Yes, we ultimately need to control the valve with a computer.

Yes, cost overkill, whichever, we should be able to come up with something for much less than a grand for a valve. I am not yet sure if we are closing in on an air actuator or not though.

 

[shingadaddy]

Okay.. IF approx 600 dollars for the servo system is tolerable, and if interested, do me a favor. I can't get to EBAY from here because it's blocked by the network gods.

If you can get to EBAY, Do a seach for SM3430D or SMartMotor or Animatics.
A few days ago I saw a guy that works on industrial servo stuff and had 3 of these for sale. Guaranteed to work. Even had one with a gearhead. In the 400 to 600 dollar range. These are normally 1500 - 1800 dollars or so JUST FOR THE MOTOR/SERVO, and are fantastic. I have first hand experience with these. They are a complete servo system integrated into the motors.
Motor data
**broken link removed**

These are a steal at the price but will provide excellent position and velocity control. Used with a gearhead they can produce the torque you mentioned. We use these a lot and have excellent results from them.

They are controlled via RS232 serial data. We use RS422 for a distant application and convert it to RS232 right at the back of the motors.

Just a thought if interested in a rotary solution.

 

[shingadaddy]

Well they seem to be gone. They could make your everyday faucet a precision control device. Oh well.

 

[fastline]

OK, someone else has recommended a R/C high speed servo which can perform at .1sec at 90* and have 100in lbs of torque and cost less than 100 bucks. I am very inclined to look at this though I di not need or want R/C performance due to the concern of inconsistent performance. However, we could possibly bypass certain parts of the circuit. They run low voltage, have a gear set, are small, and may be worth looking at.

Thoughts??


EDIT: upon a closer look at secs, I guess the performance can be 100-400oz/in of torque so a little light on torque but I think we are on the right track with this. basically just a PWM input relative to what position we desire of the valve opening. Is there a similar device out that has a more robust build but similar in function, speed, etc? I think this is well on the right track but we do not require light weight really or near this compact. Do they make compact stepper motors or something with small gear reduction?

 

[shingadaddy]

Yeah. high speed usually = lower torque. An R/C servo, as I remember the ones I have seen/delt with aren't known for BIG torquiness. Big being relative I know but...100 inch-ounces might be more in their ball park but even that is probably not *continuous*. Probably can find some though. I've seen some fairly large ones but they certainly ain't cheap.

There are some smaller smart motors on Ebay. Can't get to Ebay from here but remember them from looking last night at home. These could control flow linearly with a gate or rotary (faucet type) valve but it sounds like your determined to go PWM (the fuel injector type route). I have a hard time wrapping my head around that approach with just about any rotary motor, unless it was driving a cam shaft arrangement.

Good luck with it. Keep us posted on what you wind up with.

 

[navidbox]

i want to design an automated shelter system that when there is the sun shines the optical sensor control the DC motor to close the shelter door and when it is not any shine it will be closed,please help me

 

[shingadaddy]

navidbox, instead of hijacking some one elses thread (subject) you'll probably get a better chance of a response if you start your own.

Your description is also vague in that you state you want it "CLOSED" whether "shine" or "not any shine"

Otherwise welcome to a very informative forum.

 

[KMoffett]

navidbox,

Please do not "hijack" other people's threads. This is the second thread you've hijacked today with your question. Post your own thread to get attention to "your" needs.

Ken