[labnetwork] Specification for clean dry air (CDA)
Vito Logiudice
vito.logiudice at uwaterloo.ca
Fri Jun 10 14:52:03 EDT 2016
Hi Bob,
For the most part we use cryo N2 throughout the fab for our tool pneumatics and pump purges whereas we use CDA for gas cabinet panel pneumatics. The CDA compressors serve the entire building (280,000sq.ft with a good chunk of that being lab space) in addition to the fab. The compressor setup is maintained by the university’s Plant Operations group with which we made it a point to build an excellent relationship with early on during the building’s construction phase. We’ve also made it a point of maintaining that relationship so they are generally very good about maintaining all systems outside of my team’s direct control but on which we are extremely dependent.
If it can help I’ve appended the design specs for our CDA system. I know I’m going to regret putting this in writing but we have had no CDA failures that I can recall in the four years since we took occupancy of the building.
Best,
Vito
University of Waterloo
2.8 Clean Dry Air System
.1 System :
1. .1 duplex compressor arrangement,
2. .2 skid mounted,
3. .3 factory assembled and tested, with:
* (a) desiccant air dryer,
* (b) coalescing pre-filters,
* (c) after-filters c/w gauge,
* (d) bacteria retention filters,
* (e) filter/pressure regulator,
* (f) control panel,
* (g) air compressors.
.2 Clean Dry Air COmpressors
1. .1 Two stage, water cooled, oilless rotary tooth, electric driven compressors c/w intercooler:
2. .2 duplex arrangement with two compressors, one to run and one standby
3. .3 fitted with discharge temperature sensors mounted on each compressor and wired to shut down compressor and initiate high discharge temperature alarm if temperature rises above normal.
4. .4 capacity and horsepower for each unit as follows;
* (a) SCFM @ 130 psig 204 with 14.7 psig, 68°F inlet temp and 36%RH.
* (b) Power input 37.3kw (50HP)
* (c) Compressor model Atlas-Copco model # ZR55VSD (2 required)
5. .5 after-cooler and discharge air water separator with water drain trap on each compressor.
Standard of Acceptance
Class I
(a) with capacity 450 L (120 usgal)],
(b) constructed of carbon steel as an unfired pressure vessel in accordance with to
CSB51,
(c) cylindrical tank with dished ends and supporting legs for vertical mounting, (d) designed for 1030 kPa (150 psig) working pressure,
(e) fitted with;
* ! inlet air connection
* ! outlet air connection
* ! pressure relief valve
* ! pressure gauge and
* ! bottom drain with automatic drain valve.
.3 Air dryer system: Desiccant air dryer:
1. .1 Type:
* (a) Factory assembled and tested, skid mounted package.
* (b) two column heatless regeneration type with automatic switching between beds,
* (c) columns, heads and casings of dryer body manufactured from stainless steel,
* (d) design pressure: 1030 kPa (150 psig) pressure rating,
* (e) ball valves at inlet and outlet of dryer,
* (f) pre-filters, after-filters and bacteria retention filters in duplex arrangement with ball
valves for shut-off on inlet and outlet of each filter housing.
2. .2 Desiccant dryer control panel:
* (a) 120 volt/1 phase/60 Hz control panel,
* (b) panel face mounted pressure gauges, pre-wired alarm and operating sensors, relays,
switches, pilot lights and terminal strip for external alarm connections.
* (c) pressure gauge and pressure sensor with DISS, check valve, and nipple on outlet piping
from dryer package, on downstream side of after-filters and bacteria retention filters, to
detect "Dryer Pressure Drop High" alarm,
* (d) moisture sensors, timers and switching valves and solenoid valves to control switching
and regeneration,
* (e) internal self diagnostic circuitry and alarm contacts for "Dryer Switching Failure" alarm,
* (f) pressure gauges between prefilter and dryer inlet, between dryer outlet and after-filters
and between after-filters and bacteria retention filters.
Standard of Acceptance
N Class I Inc. Model # MG400X1
N Pneumatic Products Canada (PPC) N Aimark- Travers (Hankinson)
.3 Performance:
Parameter
Rating
Rating
Desicant per bed, minimum
4.5 kg
(100 lb)
Flowrate
11328 litres/min
( 400 scfm)
Inlet pressure
1030 kPa
(150 psig)
Dewpoint temperature
-40°C
(-40°F)
.4
Filter / Pressure Regulator System: .1 two pre-filters,
Dewpoint temperature
-40°C
(-40°F)
.5
1. .2 two after-filters rated 0.01 micron filtration with an efficiency exceeding 99.9999% D.O.P.,
2. .3 two activated charcoal filters,
3. .4 filter element change indicators ,
4. .5 automatic drain valves except on charcoal filters, and
5. .6 dual line pressure regulating assembly consisting of two pressure regulators, outlet pressure gauges, inlet and outlet isolation ball valves and pressure relief valves, located downstream of charcoal filters, arranged so that isolation of one filter / regulator will not affect operation of second filter / regulator.
Standard of Acceptance
N Norgren - Excelon
Pre-filters:
1. .1 high efficiency coalescing type, rated 0.01 micron filtration with an efficiency exceeding
99.9999% D.O.P.,
2. .2 initial (dry and clean) pressure drop of not more than 6 Kpa (0.9 psig) (1030 Kpa (150 psig) pressure rating,
3. .3 epoxy coated glass fibre media,
4. .4 NPT 1 connections, and
5. .5 external automatic drain
Standard of Acceptance .
N Hankison 3100 Series-T100-08F -48
N PPC MCD-1-100-1G16 housing with POS-1001SU element
Prefilter automatic drain:
1. .1 adjustable time cycled automatic drain,
2. .2 timer, adjustable for both interval and duration,
3. .3 direct acting, normally closed solenoid valve rated at 1030 Kpa (150 psig),
4. .4 NPT 1/4 or 1⁄2 connections, and
5. .5 EMAC 4 construction with adapter for 13 mm (1⁄2 in) conduit.
Standard of Acceptance
N Class 1 Model MG400-PF N Hankison Model 532
N PPC Model PDV 100
1. .6 liquid sensor,
2. .7 direct acting, normally closed solenoid valve rated at 1030 kPa (150 psig),
3. .8 NPT 1/4 or 1⁄2 connections, and
4. .9 EMAC 4 construction with adapter for 13 mm (1⁄2 in) conduit.
Standard of Acceptance
Hankison Model 541 PPC Model IDV 2000
.7 After-filters:
1. .1 "absolute" particulate removal type (0.9 um),
2. .2 rated 0.01 micron filtration with an efficiency exceeding 99.9999% D.O.P.,
1. .3 initial (dry and clean) pressure drop of not more than 2 kPa (0.3 psig (1030 kPa (150 psig) pressure rating,
2. .4 cellulose media,
3. .5 stainless steel housing, and
4. .6 NPT 1 connections.
Standard of Acceptance
N Class 1 Model MG 400-AF
N Hankison 3100 Series-T100-08F-48
N PPC MCD-1-100-1G16 housing with PCS-1001AF element
.8 Bacteria retention filters:
1. .1 "absolute" particulate removal type (0.2 um),
2. .2 initial (dry and clean) pressure drop of not more than 2 kPa (0.3 psig (1030 kPa (150 psig) pressure rating,
3. .3 hydrophobically treated media,
4. .4 stainless steel housing, and
5. .5 NPT 1 connections.
Standard of Acceptance
N PPC Ultipor SDL-2-AR16
1. .9 Air intakes:
* .1 Mufflers and filters to be mounted on each pump or compressor inlet.
* .2 Intake filter housing to have quick release fasteners and to be rated for air flow capacity of pump or compressor with efficiency greater than 98% when challenged with 6 micron particles.
2. .10 Clean Dry Air Control System:
* .1 mounted in NEM1 enclosure,
* .2 programmable logic module,
* .3 main disconnect switch,
* .4 three variable frequency drives with bypass contactors and circuit protection for each compressor, for future.
* .5 manual-auto-off selector switches for each compressor, for future.
* .6 control transformers with primary and secondary circuit protection.
* .7 two dryer auto/off selector switches,
* .8 one continuous/controlled dryer purge selector switch,
* .9 internal pressure sensors and pressure switches for controlling stop/start operation of compressors,
* .10 duplex compressor package for future control through Allen-Bradley Series SLC 500 Programable logic controller with alternating strategy to equalize compressor run time, and coordinate automatic back-up from stand-by unit.
.12
visual and audible alarms and BAS output contacts for;
* (a) electrical overload,
* (b) com pressor high disch arge tem perature
* (c) primary control transformer failure
* (d) lag/failure alarm
* (e) dryer switching failure
* (f) dryer low discharge pressure, and
* (g) high dew point,
Automatic controls sequences;
* (a) start lead compressor when pressure falls to 675 kPa (98 psig)
* (b) stops lead compressor when pressure reaches 703 kPa (102 psig)
* (c) start lag compressor, when system pressure falls to 648 kPa (94 psig)
* (d) stops lag compressor, if provided, when pressure reaches 665 kPa (95 psig)
* (e) alternate assignment of compressors between lead, lag, and standby.
* (f) runs compressors together under peak demand condition with adjustable time delay (0-
20 seconds) between start of lead and lag unit.
* (g) adjustable minimum run timer on each compressor
--
Vito Logiudice P.Eng.
Director of Operations, Quantum NanoFab
University of Waterloo
Lazaridis QNC 1207
200 University Avenue West
Waterloo, ON Canada N2L 3G1
Tel.: (519) 888-4567 ext. 38703
Email: vito.logiudice at uwaterloo.ca<mailto:vito.logiudice at uwaterloo.ca>
Website: https://fab.qnc.uwaterloo.ca
From: <labnetwork-bounces at mtl.mit.edu<mailto:labnetwork-bounces at mtl.mit.edu>> on behalf of "Robert M. HAMILTON" <bob at eecs.berkeley.edu<mailto:bob at eecs.berkeley.edu>>
Reply-To: "bob at eecs.berkeley.edu<mailto:bob at eecs.berkeley.edu>" <bob at eecs.berkeley.edu<mailto:bob at eecs.berkeley.edu>>
Date: Thursday, June 9, 2016 at 5:42 PM
To: Labnetwork <labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu>>
Subject: [labnetwork] Specification for clean dry air (CDA)
Labnetwork Colleagues,
I recently contacted Dennis Grimard eho is helping design and build MIT's new lab to learn their specification for their compressed dry air (CDA). Dennis is terrific with numbers and engineering data. Dennis suggested it might be useful to broaden my query to the labnetwork. This begs the questions, how do other facilities specify their CDA and who supports their systems?
At the outset I’ll comment many university labs use their campus engineering maintenance support to service utilities and specs may not be at one’s finger tips. And, some universities have central plants for utilities which serve a broad number of facilities. In the case of the Marvell NanoLab we have virtually all our utilities contained within our sub-fab and we have chosen to maintain most utilities e.g. our acid waste neutralization system, air handlers CDA, DI water, LN and process cooling water system because we are so dependent on them.
My question is what are reasonable specifications for CDA? I realize this is a difficult question to answer because CDA usage will be based on an equipment load. Perhaps adding a labs square footage helps to scale an answer?
The UC Berkeley Marvell NanoFabrication lab’s CDA is derived from two Atlas Copco 117 cfm (3,32M^3/min) screw compressors operating in a lead/lag configuration which deliver to a 200 gallon storage vessel, then to an Air-Tak brand dryer and Zander particle filters before delivery to the lab. Our CDA delivery specification is 90 psi at a dewpoint of -70F (~16 ppm H2O). We began with a dewpoint spec of -90F; however, we relaxed this spec. to reduce the work of the air dryer with wearable, moving parts. As backup, to facilitate the orderly shutdown of equipment and for brief periods to do CDA system maintenance our delivery is configured to automatically cross over to the lab’s cryogenically derived process N2 when the pressure falls below 70 psi. Such a crossover can support the lab for several hours using N2; however, the associated LN vessel vaporizers do not have sufficient capacity to run on cryogenically-derived N2 for extended periods of time – they ice over.
As has been previously noted, a few years ago we substituted CDA for N2 purging on a select number of dry pumps to reduce our N2 costs. The pumps switched to CDA were pumps which service equipment that does not pump acid-gases, flammables or pyrophorics. This has been a great success. The downside; however, is we are now peaking our CDA demands to greater than a single compressor can sustain. This makes us vulnerable should we lose a compressor.
Comparing how various research fabs spec CDA has value.
Regards,
Bob Hamilton
Robert Hamilton
University of CA, Berkeley
Marvell NanoLab Equipment Manager
Rm 520 Sutardja Dai Hall, MC 1754
Berkeley, CA 94720
Phone 510-809-8618 (desk - preferred)
Mobile 510-325-7557 (my personal mobile)
E-mail preferred: bob at eecs.berkeley.edu<mailto:bob at eecs.berkeley.edu>
http://nanolab.berkeley.edu/
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