Fast opening valve for water flow control. 1

[nodalDOF]

I am very new to valves and pumps stuff and need some help choosing a valve (with actuator) for one of our experiments. Following are the requirements

1) Application: liquid (Water) flow control
2) Fast opening (Fraction of a second (<0.1sec preferred)).
3) Size: 3"
4) Pressure: Max 500 psi

Not sure whether i provided sufficient information. The 2nd requirement(fast opening) is the most important. Any suggestions on what type of valve fits better for this application, and renown sellers would be helpful.


Thanks,
Nodal DOF

 

[gerhardl]

The problem is not the valve (even if you do not give flow cofficent necessary) but the opening time required.

To my knowledge this time would only be found in special (and very costly) explosion protection fastclosing devices: knifegate type valves, gas or air actuated from special cylinders.

The actuating force is given by a compressed gas in a cylinder/vessel. Gas kept in place behind a bursting disc and released by penetrating (to fully open the large diameter bursting disc) by internal 'pistol' fired 'bullet'.

Suggestions for more practical applicable and economical solutions:

a)Also commercially avilable:

3" ball valve to obtain full,unrestricted opening. 90 degree opening movement by single acting air closing - spring opening mounted actuator. Oversized spring force and /or actuator. Large or enlarged air release opening. Air release not through normal, often very restricted solenoid valves. (Faster and larger valves and devices exist).

Some emergency shut down types actuators-(already adapted for more 'normal' emergency opening time than explosion protection of pipelines) are also directly available on market

b) Special-made (at own workshop?) spring loaded, fallweigth or cylinderd devices directly acting on spindle or lever, if fast enough.

 

[Ashereng]

For really fast opening/closing, I would probably try a 1/4 turn ball valve first, with a really reall big actuator. You can get some amazing torques with a pneumatic actuator, and there are some really really big pneumatic actuator.

Call up a pneumatic actuator vendor and see what they have: maybe try Bettis or Ledeen?

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[nodalDOF]

gerhardl and Ashereng, Thanks for your suggestions. I am considering the ball valve as you guys suggested. I will post here back if it works out.

Thanks,
Nodal DOF

 

[Ashereng]

Sounds good. The key is the actuator. 0.1 sec is very very fast.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[ballvalveguy]

Hi Nodal,

I would recommend a vane type actuator over a rack and pinion (e.g. Kinetrol). You will also need to use a standard solenoid valve (Asco) as a pilot for a larger solenoid valve (Versa). Things that will affect the speed are the following: spring return vs double acting actuator, full or standard port valve, does it have to be fast opening and fast closing or just one.

 

[ballvalveguy]

Hi Nodal,

Last month we did a 2" metal seated valve in less than 0.3 seconds opening and 0.5 seconds closing and could quite easily have done it quicker if needed. We used an Asco HV264700003 as the pilot, a Versa VSP 3501 as the fast acting solenoid and a Kinetrol actuator. I don't see why you couldn't get the opening that quick with a bit of tweaking. Our main problem was measuring the speed, but we managed! If you're interested in how we measured it, I can let you know.

 

[nodalDOF]

ballvalveguy,

Very interesting! I am searching for similar timings. It has to be fast opening but the closing time could be about 03-0.5 sec. What type of media is it for? Is it possible to achieve with out pilot valve? I searched for the part numbers you mentioned in their webiste but could not find them. Could you please give me more details.

Thanks,
Nodal

 

[ScottyUK]

A spring discharge, hydraulically charged actuator arrangement is very fast, compact and disturbingly powerful. This mechanism is used for certain designs of HV transmission system circuit breakers - typically gas insulated types - with discharge (opening) times in the low ms range and a spring recharge period of maybe 3 or 4 seconds. I guess that is too slow for your application but I've posted it for the future reference of anyone reading the thread.


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Sometimes I only open my mouth to swap feet...

 

[Valvecrazy]

What do you need to trigger the opening of the valve? Is it an electric solenoid or a drop in pressure that requires the valve to open? Also why does it need to open so fast?

 

[Compositepro]

In most applications I've seen that require quick acting valves such as air cannons and pulse cleaners for baghouses, the valves are either diaphragm or piston types.
The piston type would be the fastest if it is mechanically latched closed. A trigger mechanism releases the piston that is sealing a a large orifice and the fluid pressure pushes the piston open as rapidly as the fluid is capable of flowing. Then air pressure is used to reclose the valve. If air or fluid is pressure used to keep the valve closed then it can only open as fast as this can be vented and the you again have a requirement for a quick opening valve to operate your quick opening valve. But that may be adequate to your needs. On consideration that you haven't mentioned is just how much flow you require when the valve is open. We are all assuming that you need a full port opening. But a 6" valve cracked open may give more flow than a small valve that is fully open.

 

[JimCasey]

You can get a ball valve with a rack and pinion actuator to open pretty quickly. 0.1 sec might be hard to achieve, but 0.2 sec is well within the limits of technology. With a R&P actuator, the trick is to get air into it REALLY FAST. Volume booster, Pilot valve, or large solenoid valve on the air supply would be needed. Modified (larger) actuator ports would be needed. It is also necessary to get the air OUT of the spring chambers so that it does not impede the motion of the pistons. THe normal cross-drilling port must be plugged, and large vents should be cut into the end-caps.
Also you need to define whether the clock starts when you send it a signal or when the valve starts to move: the piloting and solenoid valves take a finite amount of time to change state and it can easily be 0.1 sec or more before the valve starts to move after you send the electrical signal.

Your 3" valve is not too scary, but with larger valves you must consider that there is a lot of kinetic energy in the system by the time the valve gets fully open. If you just crash all this moving mass into the actuator stops, the actuator won't go too many cycles before something breaks. External, beefy, travel stops are necessary on a high speed valve to absorb the energy at the end of the stroke.

This being said: If you yank a valve on water service open in 0.1 sec, the water column will just be sitting in the pipe and the line pressure will have to accelerate the water. It will take a helluva lot longer than 0.1 sec for you to achieve the steady-state flowrate. You will likely see no difference in the flowrate between a valve that opens in a half second and your 0.1 sec valve.

I assume you know that if you try to CLOSE a 3" water valve in anything remotely close to 0.1 sec, you better have earplugs, hard-hat, snorkel, and a floatation device on because it's going to rip the pipe completely out of its fittings and flood that section of the plant. We're talking devastation of near biblical proportions. Probably even an entry into your permanent record.

 

[scotcal]

We are a valve automation centre, and have done these fast applications before.
We use a spring return pneumatic actuator (spring to open)
and a large pilot valve to get the air out of the actuator very fast. You will need to advise the actuator supplier that you will be cycling the actuator this fast, as the standard build actuators will not last very long at these fast speeds. The actuator may require oversized exhaust ports to get the speed, and depending on actuator style selected, special build on bearings/yokes ect and end stops.
The Kinetrol vane actuator is good for fast speeds - but will need special end stops. Aviod Rack & Pinion deisgns as the rack gears will break. Special build scotch yokes can be used ( Rotork - Bettis ) 0.1 sec will be tough to achieve without spending a lot of $s. Do you need actuator to last a long time ? or is this for a test application. Also at 500psi - stand well back from the downstrean piping, you might just blow it apart, the spike pressures will be very high.

 

[hydtools]

I would choose hydraulic actuation. High forces and high speeds are possible. With a cylinder actuator you can get cushioning at the end of the stroke to bring everything to a stop without crashing hard stops on the valve.

With a little clever designing you could pull a gate valve open with a hydraulic cylinder. Simple, straight line actuation. With a solenoid valve, dump a pre-charged accumulator into the actuating cylinder to get a fast opening valve action.

Ted

 

[Scotsinst]

You need to define your application better.
You mention flow control and 3" (line or valve size? How did you calculate the size?) but don't mention flowrate and pressure drop. Perhaps a 1 1/2" valve is large enough for the flow to be controlled.
Also 1/4 turn valves make great fast-opening valves but lousy control valves.
What kind of system is operating the valve and why is 0.1 second opening speed required?
We have had best success at fast controlled opening (versus on-off which most of the postings deal with) with controlled opening using hydraulic actuators and a servo.
0.1 seconds is definitely achievable with a hydraulic actuator.