[labnetwork] Span gauge replacements for gas cabinets

[John Shott]

Gregg:

I agree with Dennis that Tom Britton of Critical Systems will be a 
valuable resource ... they know Air Products cabinets forwards and 
backwards.

We have a handful of older Air Products GS500 cabinets.  They are 
equipped with MKS pressure transducers.  I think that both Wika and MKS 
(and others, I'm sure) have been producing pressure transducers for uses 
like this for a long time.

Pending more detailed information from Tom Britton, there are a few 
things that you will need to try to match when looking for a replacement 
transducer ... and all pressure transducer manufactures including Wika, 
MKS, and others offer a dizzying array of part numbers and options.

The things that you will need to match include:

1. Power supply voltage.  Most commonly +24VDC.

2. Output signal: 4-20 mA is probably most common, but some systems use 
0-5VDC or even 0-10VDC.

3. Compound or "normal" gauge.  In other words, does the gauge go from 0 
PSIA or 0 PSIG to maximum pressure reading.  Many cabinets that have 
vacuum generators will use compound gauges to be able to measure down to 
0 PSIA (-14.73 PSIG) ... but your gauge has to put out what the 
controller is expecting.

4. Electrical connector or "flying leads" to match what is already in 
your cabinet.

5. Flow through or single-ended.

6. Weld joint or VCR.

7. Particularly for your silane cabinets, do you need gauges that are 
Class 1/Div 2 rated?  That is, they can't induce an explosion in the 
event of a leak.

Also, some manufacturers offer a built-in readout if you want to be able 
to see a pressure reading where you currently have an analog gauge.

If he doesn't chime in on his own, send me email and I'll give you Tom 
Britton's contact information: he will likely be able to short-circuit 
much of your search and provide you with lots of good, specific information.

Let me know if you have any further questions,

John

On 10/14/2014 2:54 AM, Dennis Schweiger wrote:
> Gregg,
>
> I'd talk to Tom Britton of Critical Systems.  He's on this site, and 
> is a regular contributor.  They have also refurbished "older" Air 
> Products gas cabinets for me.  I would expect them to have spares, or 
> could at least point you in the correct direction.  The "Span" name 
> has been bought and sold so many times, I'm not sure what banner 
> they're being offered under now.
>
> I took a look at one of our gas cabinets, we're using a WIKA guage, 
> similar to this;
>
> http://wika.us/PGT23_063UHP_en_us.WIKA
>
> Take care,
>
> DennisSchweiger
> University of Michigan/LNF
> 734.647.2055 Ofc
>
> On Mon, Oct 13, 2014 at 1:46 PM, Gregg Cure <gregg.cure at gmail.com 
> <mailto:gregg.cure at gmail.com>> wrote:
>
>     Hello,
>     We have older (circa 1992) Air Products GasGuard GG450 single and
>     dual controller gas cabinets.
>     We are using them for SiH4, DCS, PH3 balance SiH4 for various
>     LPCVD processes.
>
>     The Span pressure gauges in the pigtails and VMBs are showing
>     their age and a few of them have failed, or are no longer able to
>     be calibrated. These gauge transducers are either in the own
>     weldments connected to the lines or connected to the lines via
>     VCRs. One gauge is an analog visual unit on the secondary side of
>     the regulator with an integral transducer that sends a signal to
>     the controller.
>
>     It seems that Span is no longer a viable entity. Does anyone know
>     of a 3rd party company that sources replacements for these
>     transducers?
>
>     Thanks,
>     Gregg Cure`
>
>     -- 
>     Gregg D. Cure`
>     The University of Arizona
>     Arizona Research Laboratories
>     Nano Fabrication and Processing Center
>     1230 E. Speedway Blvd.
>     P.O. Box 210104
>     Tucson, AZ 85721-0104
>     Office: 520.626.1987 <tel:520.626.1987>
>     Cell: 520.307.2760 <tel:520.307.2760>
>     Fax: 520.626.7877 <tel:520.626.7877>
>     Website: http://mfc.engr.arizona.edu
>     Website: http://www.arl.arizona.edu/
>
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