turn on and off pump

General Composites Discussions Equipment Talk
#1

Hi, I’m new to this, I am learning a lot in the forum, but still I have many doubts, now I am facing to problem of how to control the vacuum, to counteract the bag leaks.

A precise vacuum controller may be too expensive, plus, I only need keep the vacuum as low as possible, below 28.5-29Hg.

However, make an electronic timer is very easy for me, then, I had thought to make a controller that turn on and turn off the pump for some concretes periods of time.
Example: 30 minutes off, and 1 minute on.

The question is: Is it bad for the pump, turn on and off repeatedly?. Example, if I turn on 15 seconds every 5 minutes for 12 hours. Could damage the pump?.

I need to know this to know how to set the timer.

Sorry for my English, you maybe not understand me too well.

A greeting and thank you very much

#2

smc vacuum switch with a relay. not that expensive

#3

Finally I have bought one SMC ZSE1-01-55L second hand, I’ll see that it works.

Regards and thanks

#4

Let us know how you do it
if you make it work and can described how to do all the electric connection it will be helpfull because I cannot find nowhere the " how to do"
Thanks

#5

Hi Phsledge, no problem, but I see my switch, and yours (comented in post SMC vacuum switch) are very different maybe, it’s useful to you.

A greeting.

#6

You are right they are very different
But anyway it would be interesting to know how the kind you have work
I will also upload about mine when it will be setup
Thanks

#7

If you need a low vacuum, do not turn the pump off.

If you have leaks, don’t vacuum it until you FIX the leaks.

I would think that constant cycling on and off, will not only hurt the pump, it will waste a LOT of energy. Motors take a lot of power to start up.

#8

That last sentence can be dependant on setup. The systems I make are switched, and when used normally, the pump switches on for perhaps 15 seconds, every 10 minutes or even more.

#9

Hi Guys Newbie here.
Why would you want to turn the pump off ? forgive me if i am wrong but i believe your component will be stronger with the minimum amount of resin to layup material. as in OCLV Optimum Compaction Low Volume, leave the pump running to extract as much resin as possible before it starts to Gel.
Just a thought.
Regards
Mekanik

#10

Hi all.

The problem is that the pump can not be on for long enough, certainly not good for any pump being operated for 12 hours, maybe it’s deteriorate unnecessarily, because maybe with a few power cycles might have been enough, also consume a lot of oil, right?

In fact now I have a compressor fridge (I’m looking to buy a better pump), and this can not be working more than a few minutes.

As riff42 says, the ideal would don’t turn off the pump, but I guess that is not always possible, especially in systems with oil, right?

Herman, my idea was similar to that, see how my system loses vacuum, and based on this, setup the timer, giving him a wide margin of safety.

Example: if my system loses 1 Hg per hour, and I need to turn on the pump for 30 seconds to recover it, I would configure timer to activate for 30 seconds every 15 minutes, this would ensure a low vacuum, the problem is that, it wouldn’t be good for electric motors, like told riff42, and I don’t know if it is bad for the mechanics parts charged to make the vacuum from the engine. So I asked.

For example one air condition pump wouldn’t be desing to support work intermittently, then this may be bad for the pump.

Greetings

#11

Hi Compoforo
I was unaware what type of pump you were using, I used to work @ Bae Systems here in Barrow and following Hydro of HPA pipework we would drain the system as best we could and then run a vacuum pump on the pipework to remove the remaining water,these used to run for weeks 24/7 with an Engineer just monitoring the level and condition of the oil changing or running the ballast as required.These were Edwards pumps,i have a pfeifer that i run continuosly whenever i have a job on the go,however oil vapour is an issue as i have not got round to getting an exhaust filter yet.
Take care
Kindest Regards
Mekanik

#12

Hi,
About the oil problem. Could I make a homemade oil vapour filter?
They also told me that if you are running the pump for several hours, I must use an aluminosilicate trap to stop oil back-streaming from the pump to my mold, but I have not found any information about this! maybe, Also Has it another name this type traps / filters?

PS: I’m trying to get a Edwards Speedivac 2.

Greetings

#13

I would say, if your pump is not capable of staying on for the time the resin needs to cure, invest in a better pump, or add a LARGE vacuum reservoir. Then you can have a vacuum switch, or timer, to pump down the reservoir less frequently than a few times a minute.
I’m sure you can make your resin catch pot a reservoir as long as it is all sealed well, and large enough.

#14

Hi Compoforo
Have to admit i was not aware of the oil contamination problem, but i am a novice @ this game so it could be possible. re oil mist filter if you find any information please post as the price for the Edwards gear is not cheap. Catch pot, i made mine from an old pressure cooker,removed the relief valve and made an adaptor with a length of pipe stopping about 3 inches from the bottom of the pot, place a disposable container in the pot to catch the resin, drill the lid for your vacuum connection. I was concerned that the seal would not work as it is designed to seal with internal pressure but mine seems OK.
PS the idea was not mine, saw it on a U-Tube vid.
Hope that helps.
Kindest Regards
Mekanik

#15

I use a vaccum advance with a micro switch attached. Works good with my little fridge pump. Got the idea here- http://www.seabreeze.com.au/Articles/Windsurfing/How-to-build-your-own-vacuum-pump-for-under-50_1293413.aspx I rigged Mine a little different, I got a cams adjustable vaccum advance from eBay, micro switch from radio shack, and springs from discount auto. Rigged the whole thing up on a piece of wood with a long screw to make the set up adjustable.

#16

Hi all.

Now I get the smc switch , but unfortunately it did not work … now I’m looking for a SMC ZSE40, I think it is worth paying a little more, to visualize accurately the vacuum and have an analogue output can be interesting.

Regarding oil filters for the vacuum side I haven’t information, perhaps not really necessary…

greetings