Tom: A couple of comments. 1. I have never found a good monitor and control system that didn't bring more headaches than it was worth. However if you have a fairly steady thru put of product i.e. square footage being processed in the washer and you know your dragout in gals/hr you can put in a chemical feed pump. This would continually dose the wash sump at a given rate (ml/min) or whatever units and time you want. This is typically tied into the washer control system so it's only running while product is being washed. This will give you a pretty good steady state concentration. 2. Regarding bath turnovers and mask and solids loading. Be careful on your assumption for wash bath turn over. You do not actually turn the complete bath over in 12 shifts and create a fresh bath. Example: You have a 1 liter beaker filled to the top with water that has red dye. You add a second liter of water without dye to this, mixing into and overflowing out of the original beaker. After adding the second liter of water to the original is the water now clear water white? No it is pink. You have diluted the original but not replaced it. To make it a little more complicated you are constantly adding more dissolved solids and water soluble mask as you process additional boards. So you are continually adding contaminates and removing a percentage thru dragout. Regards Michael Barmuta Staff Engineer Fluke Corp. Everett WA 425-446-6076 -----Original Message----- From: Tom Gervascio [mailto:[log in to unmask]] Sent: Thursday, November 20, 2003 4:22 AM To: [log in to unmask] Subject: [TN] Automatic monitoring systems for in line cleaners We are considering using an automatic system to monitor and control additions of a saponifier to our Electrovert H400+ wash. Any recommendations on systems that other's have used? Any trade-offs on closed loop monitoring systems using pH versus refractometer? I thought that if you use water soluble masks that the dissolved materials might influence the dissolved solids measured with refractometer. However it seems that drag out with normal operation approaches 7 gal/8 hour shift. with a prewash and wash capacity of 95 gallons this means that over 12 shifts that the wash should be turned over but I suspect that all the material may not be turned over due to dead spots in the construction of the wash (i.e. 2" level in wash below a U joint that connects the prewash to the wash section). That said is location of the sensors critical- i.e. place them in these areas where the wash may be stagnant or items may settle to the bottom of tanks and heaters. Thanks for the input --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------