Source for water flow switches suitable for lasers?

Methods of cooling laser tubes

Source for water flow switches suitable for lasers?

Postby SharpeCreations » Sun Nov 14, 2010 8:33 pm

I would like to get my hands on a small, inline flow switch to serve as an interlock, protecting the laser tube from loss of flow. I have done a good deal of searching for such a thing, and all I find are industrial units for big$$, and PC cooling stuff that outputs a pulse per rev signal (acting as a flow METER). I currently have a spinning-ball flow sight in the return line, which for all practical purposes, serves just fine, although a bit restrictive to flow.

One approach I may try, is to use a Dwyer low pressure switch, similar to what is used in furnaces to verify operation of combustion blowers. I would tee the switch into the pump discharge hose, where it would close a set of contacts once the pump starts to build a little pressure. The big flaw in this plan is that it only verifies presence of pressure, not flow. If a line were kinked, and not flowing, the switch would still signal an OK condition. I am not worried about a kinked line as much as a pump failure, which the pressure switch would detect. I think I will give this a try, as I have a switch I could try out.

Ideally, I would like to find a small, cheap, inline flow switch to protect the laser tube. Has anyone found a source?

Thanks in advance!
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Re: Source for water flow switches suitable for lasers?

Postby bdring » Sun Nov 14, 2010 9:10 pm

koolance.jpg


I use this switch from Koolance. Originally I had it hooked up to a PIC chip that used it do monitor flow and power. I have not used the PIC in a while and just visually verify the flow. Look at my entries between 10/5/09 and 10/18/09 on this page.

http://www.buildlog.net/cnc_laser/build ... l#LogStart
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"If you didn't build it, you will never own it."
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Re: Source for water flow switches suitable for lasers?

Postby trwalters001 » Sun Nov 14, 2010 9:20 pm

Hi All,

If you search ebay for "proteus" and "switch", you'll find a bunch of the industry-standard flow switches for laser cooling systems.
Use this link http://www.proteusind.com/eprice/100PL.pdf to determine which model you need (flow rate and voltage).
Here's the data sheet for the one I use: http://www.proteusind.com/100_flow_switch/100TRM.pdf
If you can pick one up for $50 or less, you've got a great deal!

Tim
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Re: Source for water flow switches suitable for lasers?

Postby Mike-f » Sun Nov 14, 2010 10:44 pm

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Re: Source for water flow switches suitable for lasers?

Postby trwalters001 » Sun Nov 14, 2010 10:53 pm

Those look great!
Any idea how they work?
FSE 60W + RetinaEngrave
Coherent Model 42 60W Slow-flow CO2
Homemade 50W Slow-flow CO2
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Re: Source for water flow switches suitable for lasers?

Postby mpeele » Mon Nov 15, 2010 1:10 am

I also used the same koolance flow switch as Bart. One nice thing about it is the compability with the PC cooling products. I also got a temp sensor from Koolance. Just today I ordered a radiator fans and resivor, level sensor and tubing. Their tubing was only $0.99 per foot. Where Bart is using a PIC chip I used a AVR 328 based Adruino.
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Re: Source for water flow switches suitable for lasers?

Postby Tweakie » Mon Nov 15, 2010 8:24 am

I used the Gems flowswitch. I does however increase the back pressure in the flow so I have it fitted before the tube rather than after.

Tweakie.

Image
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Re: Source for water flow switches suitable for lasers?

Postby Mike-f » Mon Nov 15, 2010 9:10 pm

trwalters001 wrote:Those look great!
Any idea how they work?


I belive they have a spring loaded piston with a magnet inside and a reed switch outside the tube, basic but reliable and cheap!
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Re: Source for water flow switches suitable for lasers?

Postby SharpeCreations » Tue Nov 16, 2010 2:54 am

Great suggestions! I really like the Gentech switch for the simple design, and low cost. Looks like Newark sells them. heres a link: http://www.newark.com/gentech-international/fs-10/flow-switch/dp/94M7371?in_merch=Popular%20Sensors&in_merch=Popular%20Products&MER=PPSO_N_P_EverywhereElse_None

Thanks for the leads!
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Re: Source for water flow switches suitable for lasers?

Postby trwalters001 » Tue Nov 16, 2010 2:28 pm

The Gentech switches do look good.

NOTE: this is on the Newark page: "Non-Cancelable/Non-Returnable Handling Fee $20 per order"

If several of us wanted to buy these, maybe we could do a group buy and spread the $20 out a little.

Tim
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