[labnetwork] Span gauge replacements for gas cabinets

Wed Oct 15 11:40:39 EDT 2014

Just to follow up on the discussion points that John made.

Air Products previously used Span's Indicating Pressure Switches and Transmitters with their GG450 and GG250 gas cabinets, rack units and VMBs. The measurement units were all in PSIG and for the transmitters, their output was 4-20mA. Excitation voltage was 11.5+ to 28 VDC. I don't remember any connection from Span other than Lower Mount and Center Back VCR or NPT. All of the pressure measurement devices used by Air Products from the GG450 to the latest AP10 and AP11 systems, all use the AMP style connector, which plugs into their AMP box. We add these connectors with all the electrical devices we put into their systems.

Span had an interesting run. For all who care, they actually spun off their liquid filled division to the Thuemling Group who provides gauges for most of the fire trucks made. The UHP division was private labeled by the tubing manufacturer Cardinal UHP back in the late 90s, and then sold to Mykrolis years ago. Mykrolis sold to Celerity, who continued with the MFCs, but pretty much ignored the pressure measurement side. Celerity sold to Brooks, who has taken an interest in the line and now somewhat produce it for sale. Kind of sad since Span was the premier brand back in the late 80's through mid-90's.

For switches today, we use the Wika 230-15 series as they are kind of the sole survivor in this market. http://wika.us/230_15w_851_3_en_us.WIKA  The indicating transmitter is the one that Dennis refers to. Ametek previously made the IPS and IPT indicating switches and gauges, but they ran into issues with the sensor and told me a little over a year ago that this wasn't high on their priority list anymore.

For transducers, we use the MKS 870 that John referred to, the Setra 225G or the Wika WUC-10. These are all PSIA for the readout and 4-20 mA. Excitation voltage is still the 11.5+ to 28 VDC.

Air Products originally went with all flow-through transducers with the thought that they could minimize surface area and eliminate a connection by staying away from the dead leg style transducers, but that produced an issue with maintainability if the transducer went bad. They also has problems with the strain gauges due to how the manufacturer had to build the body. Delamination and torque problems plagued Span and other manufacturers back in the 90's. Today Air Products, and CSI, go with dead leg style transducers, as they are easy to service and extremely reliable.

I hope this was on interest and helped.

Best to all,

Tom

Tom Britton
Director of Sales
Critical Systems, Inc.
Direct: 208-890-1417
Office: 877-572-5515
www.CriticalSystemsInc.com<http://www.criticalsystemsinc.com/>

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From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of John Shott
Sent: Tuesday, October 14, 2014 8:44 AM
To: Dennis Schweiger; Gregg Cure
Cc: Fab Network
Subject: Re: [labnetwork] Span gauge replacements for gas cabinets

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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