[labnetwork] Shared Chiller [for equipment cooling] Issues

Tue Sep 23 11:02:20 EDT 2014

Dear Bob,

Thank you for your reply.

The pulsation dampers is for ripples in the circuit? or something else. My
query is when we open or close any of these process equipment cooling water
valves, does this generate a ripple which may cause the flow sensor in
other tools to get activated. Please see a document attached in which a
plate heat exchanger with cooling water has a expansion tank in it. Do we
need this tank or is there any other way to tackle the issue.

I am in Process, but from last few months these chiller issues causing
tripping of equipment has increased, so wanted to know about such cooling
water circuits where chillers are shared.

Thanks,
Kamal.

On Tue, Sep 23, 2014 at 8:03 PM, Bob Hamilton <roberthamilton at berkeley.edu>
wrote:

>  Kamal,
>
> The Microlab, which preceded the Marvell NanoLab, had issues with big dips
> in city water pressure when classes let out. Our building was also a
> teaching building and on the hour, when classes ended and restrooms were
> heavily used, we'd see large dips in pressure that resulted in our reverse
> osmosis water system shutting down from low pressure. We also had a problem
> with inertia. On start-up, the RO pump dipped the inlet pressure because of
> the inertia of the water column.
>
> We solved the problem by tee'ing in a 100 gallon expansion tank (sometimes
> called a draw-down tank). This required adding a check valve to prevent the
> tank from back-feeding the building. This tank was equipped with an air
> bladder pressurized to 80 psi which was the motive force to keep water
> under pressure. It worked flawlessly. These tanks are often used in
> association with well pumps so pumps do not end up close-cycling. A switch
> with a dead band of ~ 20-30 psi is then used to cycle the pump.
>
> Having shared this, it does not seem applicable to your chiller issue.
> There are devices with smaller volumes called pulsation dampers which
> mitigate the high frequency pulses from gear pumps. Perhaps that is what
> someone has recommended?
>
> Bob
>
> On 9/22/2014 10:32 PM, Kamal Yadav wrote:
>
> Dear All,
>
>  Thank you very much for sharing your experiences.
>
>  There is a design where one puts an expansion tank on the return line
> for these shared chiller, probably to avoid ripples, flow shocks, that one
> gets when another tool is being switched ON or OFF. I found a document
> which is attached which talks about designing such cooling water circuits.
> This water is only for process equipment cooling, and not facilities
> equipment cooling.
>
>  If anybody has worked without these expansion tanks, and if using flow
> settlers is enough that would be great to know, we may need to modify our
> circuits little bit, if needed.
>
>  Thanks,
> Kamal.
>
>
>
>
> On Mon, Sep 22, 2014 at 8:37 PM, Bob Hamilton <roberthamilton at berkeley.edu
> > wrote:
>
>>  Kamal Yadav,
>>
>> It is difficult to diagnose your issue given the information in your
>> e-mail. It is possible a single tool is using more water than it needs and
>> therefore reducing the available volume to tools with higher impedance
>> cooling circuits. You may also have a blocked cooling channel in a tool(s).
>> Consider running water through them, backwards and into an open drain or
>> bucket to back-flush them.
>>
>> A question; what purpose does this chiller serve? Does it supply
>> deionized for rf cooling circuits where the resistivity of the water is
>> important or does it simply provide equipment cooling? Is it a heat
>> exchanger (HX) or is it Freon-based centrifigal chiller? Do you have a
>> rotameter in the cooling loop?
>>
>> Assuming the conductance of various tools allows most of the process
>> cooling water to flow through those tools with lowest impedance consider
>> adding "flow-setters" to your tools or just to the tool using too much
>> water. There are dynamic version of flow-setters that adjust flow to a
>> specific volume of liters-per-minute and maintain this constant flow over a
>> range of pressure.
>>
>> At the Marvell NanoLab we've used flow-setters made of brass, PVC and
>> stainless depending on the application. If you choose PVC versions, I'd
>> pick male pipe thread (mpt) over female pipe thread (fpt). We try and avoid
>> threading metal mpt fittings into plastic fpt fittings because the plastic
>> fitting may crack at some part of its service life causing flooding.
>>
>> Appended are a few US links that provide an example of the device I am
>> referring to. I've also seen them on EBAY.
>> http://www.deanbennett.com/dole-flow-control-valves.htm
>> http://www.haysfluidcontrols.ca/hays_automatic_flow_controls_2305.htm
>>
>> http://www.merrillmfg.com/product/08-WellPoints/Merrill-Valves/features.php
>> http://www.plastomatic.com/fc.html
>> http://www.swtwater.com/catalog/1318_flow_controls.htm
>>
>> Regards from the MNL,
>> Bob Hamilton
>>
>> --
>> Robert Hamilton
>> University of California at Berkeley
>> Marvell NanoLab
>> Equipment Eng. Mgr.
>> Room 520 Sutardja Dai Hall
>> Berkeley, CA 94720-1754bob at eecs.berkeley.edu
>> e-mail preferred
>> My personal mobile: 510-325-7557
>>
>>
>> On 9/21/2014 11:22 PM, Kamal Yadav wrote:
>>
>>  Dear All,
>>
>>  We are facing chiller [for cooling water for equipment] issues, most
>> likely flow issues, probably due to using same chiller for multiple
>> equipment. Though chiller total cooling capacity is able to provide
>> flow/pressure but in an shared equipment scenario, could there be issues.
>> Suddenly some equipment, in use, trips, because of low flow of cooling
>> water probably.
>>
>>  Did anybody faced these issues, are we diagnosing it correctly?
>>
>>  Thanks a lot.
>>
>>  --
>>  Thanks,
>>  Kamal Yadav
>> Sr. Process Technologist
>>  IITBNF, EE Department, Annexe,
>> IIT Bombay, Powai
>> Mumbai 400076
>> Internal: 4435
>> Cell: 7506144798
>> Email: kamal.yadav at gmail.com, kamalyadav at ee.iitb.ac.in
>>
>>
>>   _______________________________________________
>> labnetwork mailing listlabnetwork at mtl.mit.eduhttps://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork
>>
>>
>> --
>> Robert Hamilton
>> University of California at Berkeley
>> Marvell NanoLab
>> Equipment Eng. Mgr.
>> Room 520 Sutardja Dai Hall
>> Berkeley, CA 94720-1754bob at eecs.berkeley.edu
>> Phone: 510-809-8600
>> Mobile: 510-325-7557 (Emergencies only poor cell phone service in lab)e-mail preferred
>>
>>
>>
>> _______________________________________________
>> labnetwork mailing list
>> labnetwork at mtl.mit.edu
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>>
>>
>
>
>  --
>  Thanks,
>  Kamal Yadav
> Sr. Process Technologist
>  IITBNF, EE Department, Annexe,
> IIT Bombay, Powai
> Mumbai 400076
> Internal: 4435
> Cell: 7506144798
> Email: kamal.yadav at gmail.com, kamalyadav at ee.iitb.ac.in
>
>
> --
> Robert Hamilton
> University of California at Berkeley
> Marvell NanoLab
> Equipment Eng. Mgr.
> Room 520 Sutardja Dai Hall
> Berkeley, CA 94720-1754bob at eecs.berkeley.edu
> Phone: 510-809-8600
> Mobile: 510-325-7557 (Emergencies only poor cell phone service in lab)e-mail preferred
>
>
>

-- 
Thanks,
Kamal Yadav
Sr. Process Technologist
IITBNF, EE Department, Annexe,
IIT Bombay, Powai
Mumbai 400076
Internal: 4435
Cell: 7506144798
Email: kamal.yadav at gmail.com, kamalyadav at ee.iitb.ac.in
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