Can anyone share their successes or problems on the application of high cycle rate solenoid valves and actuators? I need to specify solenoids and related pneumatic components which need to operate reliably on a critical piece of equipment.

 

Responding to Stephen Wright's query:

In my experience faster response from a solenoid required that it be overdriven with a higher than nominal voltage. The use of higher
insulation class (higher temperature) was the usual solution. Another solution is to overdrive, and then cutback to the nominal voltage value
(or remove the driving voltage) when the solenoid has reached 80-85% of its travel. The latter is standard practice for circuit breaker trip coil solenoids.

However, not to lead you astray I suggest that you seek the advice of the valve or solenoid manufacturer. But, it may be easier said than done
because I find that manufacturers are loathe to develop non-standard product, primarily for liability concerns. (Ah, for the America of old).

Regards,
Phil Corso, PE
Trip-A-Lam Corp.

 

In the work I have done on slicing, packaging and printing equipment, it is not uncommon to use DC solenoid valves with mechanical activation in the
15Millisecond range with a requirement in the 2Millisecond range.

To do this requires a controller with a time based, deterministic update time for scanning inputs and outputs at 1 millisecond. The trick is to turn the valve ON 15milliseconds before it is required.

The valve usually is constant with its time to turn on and time to turn off. Don't assume these time to be the same.

It is then necessary to advance/retard the timing to meet the requirements.

 

Many clutch/brake controls do this, called overexcitation. You might check with Warner Electric.

Bill

 

At 15:31 23/03/00 -0500, Stephen Wright wrote:
<clip>
>Can anyone share their successes or problems on the application of high cycle rate solenoid valves and actuators? I need to specify solenoids and >related pneumatic components which need to operate reliably on a critical piece of equipment.
<clip>

We have applications with solenoid valves that cycle 40,000 times a day, seven days a week. I am not aware of any special problems using standard valves and cylinders. The big issues seem to be making sure the air is clean and dry enough and that the pneumatic system was properly assembled
with no dirt or hose fragments inside, and no pinched seals.

The main life problems with valves seems to be with the o-rings. Some types of valves have no o-rings, but rather simply use a very close fit. These seem to go on forever provided they don't run dry or clog up with oil or dirt.

Take a good look at the valves you are specifying, and make sure that if one does fail that it can be easily and quickly changed. Some of the newer valve styles are cheaper, but they require quite a bit of dissassembly just to get one valve out. You must expect that some valves and cylinders will fail, and plan accordingly.

If the piece of equipment is critical, then put a hardware cycle counter in the machine (to keep track of how much its been used), and make
sure you have a good PM system, and a good clean, dry air supply in your plant. If you don't have those last two items, it won't matter what valves
and cylinders you use.


At 16:12 23/03/00 -0500, Phil Corso, PE wrote:
<clip>
>Another solution is to overdrive, and then cutback to the nominal voltage
>value (or remove the driving voltage) when the solenoid has reached 80-85% of
>its travel. The latter is standard practice for circuit breaker trip coil solenoids. <clip>

I think that what you are referring to is a current driver. The driver puts out a constant current rather than a constant voltage. These are
occasionally used on high inductance loads. I believe I have seen these (years ago) in an octal base package.

The higher voltage initially applied will increase the stress on the coil insulation, which may cause premature failure. However, the voltage
stress may well be less than what is experienced from the field collapsing when the solenoid is de-energised without a snubber being installed. As you have said, the valve or solenoid manufacturer should be consulted, although I don't think this was what the original question was about.


**********************
Michael Griffin
London, Ont. Canada
[email protected]
**********************

 

I think I have missed the start of this thread, but anyway:

A simple soulution of this overdriving could be to feed it with a too high voltage, but feed it thru a resistor parallel to a capacitor. Some calculations do have to be made, but generally the resistor should limit long time voltage/current to the solenoid to normal, the
capacitor makes the inrush higher. If the source is short circuited the turn-off time will be shorter too. The capacitor have to match the
solenoid (I think approx. equal stored enery would be best option).


/Johan Bengtsson

----------------------------------------
P&L, the Academy of Automation
Box 252, S-281 23 H{ssleholm SWEDEN
Tel: +46 451 49 460, Fax: +46 451 89 833
E-mail: [email protected]
Internet: http://www.pol.se/
----------------------------------------

 

Hot melt glue applicators and other spray products use high speed solenoids. Some can go to 2000 cycles per minute with proper electronics and good valves. They do have a limited lift and need to be replaced at regular intervals. The valves I have seen used are Mac but I am sure there are other suppliers. We used Gemco electronic cam switches to operate them off
standard power supplies ( big ones but then we had a lot of valves ) The biggest problem is often the mechanical parts being moved by the air valve.

James Bouchard

 

Another problem regarding valves with 'hot melt glue applicators' ... sometimes the valves are located to close to the heated nozzle assemblies
and the o-rings in them arent high temperature 'viton' type, to increase their life spans and minimize bbq effect. Sometimes product is misapplied to the application and external influences should be minimized.... ie. locate
valve a tiny bit further away from heat source

Darren Tichbourne
President, System Integrator, CET
CompuSys Solutions
___________________________________________________________
Email : [email protected]

Website: www.CompuSysSolutions.com

 

I once had an application that required operating a pneumatic double-acting cylinder at a rate of 250 times per minute with a very fast extend-retract requirement.

I built a solid-state single-shot time-delay relay using a 555 IC chip and a 2N3055 power transistor. This relay allowed me to produce an adjustable (via a 20-turn potentiometer) 3 to 30 mS 24 VDC pulse rated at 5 A.

I used this pulse to drive a MAC model 100 4-way DC solenoid valve.

The valve control a 1" diameter x 3" stroke Miller brand cyclinder with viton seals.

One major key to successful operation was the use of mineral oil for lubrication.

Hope you find this information useful.

 

Dear Sir/Madam,

I am writing to make an enquiry about solenoid valves. Actually, I am looking for some solenoid valves with the following specifications:

1. Size: 1" and 1/2", which are for water flow at pressure of 5 bar.

2. They must have fast opening function, preferably, 1 ms (0.001 second), or better.

3. Thy must have fast closure function, preferably, 1 ms (0.001 second), or better.

It will be very grateful if you can provide me with information about the fastest respond time of solenoid valve available in the existing market.


Best regards

Ying Yang Hou (Research fellow)
Department of System Engineering
Brunel University
Uxbridge
Middlesex UB8 3PH
UK