good source for vacuum switch

General Composites Discussions Equipment Talk
#1

Anyone have any leads? I’m looking for an adjustable switch that can handle 10A @ ~240V or ~15-20A @ 115v. Preferably one that runs off the motor input power(in other words doesn’t require a separate or different power input than the motor) I have been trying to find something heavy duty, similar to a water well pump control switch(pressure) but have not turned up much. Really don’t want to spend money on a pump controller if at all possible.

My large twin cylinder Gast pump is continuous duty, but there’s zero need for it to runs continuously for 12 hours on end because a bag develops a leak that I cannot find/fix. Would rather have it cycle as needed when the reservoir vacuum drops sufficiently.

Thanks,

Adam

#2

http://www.csedistributors.com/acatalog/017-5215-Danfoss-RT-Pressure-switch-Type-RT121-017_5215.html

#3

Check ebay for a Barksdale switch. I picked one up at a surplus store for $45.00.

#4

I’m also on the look for a good vacuum switch, but i have some doubts what to choose.

I have a “Value” 2,5cfm pump without any non-return valve.

So to get the system working properly i think i will need:

A) Non-return valve - To install after the pump, to stop a vacuum “leak” when the pump is turned off;
Something like this:
http://uk.rs-online.com/web/p/pneumatic-positive-pressure-vacuum-non-return-valve-function-fittings/2550254787/

B) Programmable Vacuum switch

I have two choices available.
1 - SMC ZSE40-01-22L (http://content.smcetech.com/pdf/ISE40.pdf)

or

2 - ZSE30A-01-P-G (http://smcpneumaticsdistributor.com/smc-part-1583/ZSE30A-01-A-PG.html)

C) A 230v relay, so that the vacuum switch can operate the pump on/off. (the switch doesn’t have a 230v output)

D) A 24v power unit to power up the switch.

My doubt is going a cheaper way and get one of this http://www.pvl.co.uk/vacuum_switches/vsm_vacuum_switch_with_din_plug.html.

This way i can spare the 24v power unit and the relay, and the switch is also cheaper than the SMC ones.

On the other and i don’t have a digital vacuum gauge, that i think can be useful.

What’s your thoughts on this?

#5

The switch by PVL is totally useless. It uses a membrane to operate a microswitch. The membrane is not stable, and has a huge hysterese (in the 150 mbar range).

What you ideally want is a:

SMC switch ZSE30
Bevel for mounting the switch in a cabinet
Depending on version, a connector to mount a 2,5x4mm air pressure line (Festo, Legris)to the switch
Through-bulkhead connector for the hose
Connector to attach the hose to the rest of your vacuum system
12 or 24V power supply (24V preferred)
Solid state relais (mechanical relais are useless)
Housing
Piece of Din Rail
Through connectors (2) for wire (or use wall outlets / chassis part for connecting wires)

Putting it all together is fairly straightforward. Next week I can get the parts and do a photo series of putting one together, if you like. (one of my suppliers has all these items in stock)

Configuring the ZSE30 is a bit fiddly, keep in mind that you need to set your switchpoints as -500 mbar, not +500 mbar (took me a while to figure out…)

Indeed you also need a non return valve, any will do, as long as they are large enough for the pump capacity.

#6

Thanks Herman. Your posts are always a great help!

Can the SMC ZSE40 be a good substitute for the SMC ZSE30?

I can get a great deal on one of this (ZSE40), and for what i could understand, this one is the old/discontinued version of the ZSE30.

#7

I have no experience with the 40 but i reckon it should do thr job. Just make sure it is delivered complete. And do not pay too much

#8

This would be a godsend. And maybe alternative switches in case they cant be found her in the UK.

#9

I will try and pick up all supplies. I see the SSR might be delayed until the 4th of october, but I am look ing for an alternative.

#10

Any development on this?

#11

Working on it. Ordered some materials.

#12

Well, finally all the major parts are in. I will do a writing on the building of an electronically operated switch.

For my ease I will do a 230V 1P version (115V 1P is not much different, 400V 3P just slightly). I will equip it with 2 wall outlets, so I am pretty much independant on the pump used (as long as it has a power cord)

#13

Herman, one day you will write a book, “the bible of advanced composites” …

#14

I am about 80% of my first book: Simple resin infusions

Got the controller today. Will make some pictures.

#15

I’ve got 2 vac switches that I have used the first one I took a micro switch and rigged it up to a vacuum advance diagram from a old corvette rigged up with springs. It worked good and would switch hold a steady 27-29 inhg. Total cost was bout $15. The second one I bought on eBay I think it’s made by volt and cost $40. It was basically a fancy version of what I made and more compact but yet it would cut off at 29 inhg but not switch back on until 24 inhg. When doing infusion I haven’t needed a switch though since doing infusion since my pump isn’t running all night long. Has anyone else used these switches?

#16

Any news on a vac controller.

I could do with one, I have a tank ready waiting.

#17

Why a vacuum switch? Are your pumps overheating? In 25 years of vacuum bagging, I have never used a vacuum switch as a vacuum regulator. Before that I was an industrial electrician. Spent some time in a motor rewind workshop. Stop-start running is at least as hard on an electric motor as continuous running.

#18

For me I am more concerned about noise, but also pump wear(not motor wear) and power consumption when it runs unnecessarily. With a tank to help hold vac for some time the pump may only run for the 1/10th of the time and still keep up with any small leaks.

#19

I suppose it depends on the value of the job. My jobs are too big and expensive to risk running a vacuum switch to save a little bit of power. In my opinion fluctuating vacuum levels or vacuum regulator electrical failure are more likely than failure of a well maintained pump. As I said earlier, I was an industrial electrician. If regulating vacuum levels electrically is the best option, I would suggest a system with built-in redundancy. I have more than one pump and a back-up generator. That is my built-in redundancy :slight_smile:

#20

I have three pumps, just in case.

We make small parts continuously so the pump runs day after day for about 5-6 hours each cook so with the power costs these days I hope it could help with that?