Clean Room Application


A cGMP (Current Good Manufacturing Process) FDA compliant customer manufactures products for the pharmaceutical market and has a clean room in which he has to maintain a positive pressure in order to keep the area contaminant free.  He needed to be able to monitor this room to be sure his filters and fans were working properly at all times.  The clean room shown as room “2” below is the critical clean room so it is necessary to enter through room 1 to get to room 2 – both on positive pressure.


Clean Room


We selected a zero-center Series 2000 Dwyer Magnehelic® differential pressure gauge with an 0.25″ w.c. (water column) range either side of zero whichmakes an effective monitor for proper operation of the room pressurization system. In the example shown below, differential gauge B has its high pressure port open to room 2 and its low pressure port to room 1 – gauge A has its high pressure port open to room 1 and its low pressure port open to atmosphere. With the makeup air supply damper adjusted properly, room 2 will be a higher pressure than room 1 which is at higher than atmospheric pressure and both gauges will read positive. Should the air supply to room 2 be obstructed, gauge B will read negative. If the air supply fails entirely, both gauges will read zero. For even better security, a Series A3000 Photohelic® switch/gauge will provide automatic alarm or start-up of a backup system.





Custom “Tri-Controller” portable control system for pH, temperature, speed control.




In 1999 a research lab / pilot plant needed to control several parameters in area of their fume hoods with a portable control system that could be easily moved about.

A large beaker filled with the customer’s test solution needed to be heated with an electric mantle wrapped around the vessel, while the solution was being agitated with an over the side mixer and dosed with an acid solution to maintain a pH level. In addition, the heater was to be started up an hour or so prior to the Tech’s arrival in the morning so a timer was incorporated to bring the vessel up to temp at 6:00 am.

All of this equipment was to be in a stainless steel portable enclosure that would not take up a lot of workspace.

We first selected a ¼ din pH control and Timer and a 1/16 din temperature control to read and control the parameters. We then designed an enclosure with a sloping front and hinged cover that measured 18” x 10” x 10” and had a local sheet metal fabricator build 3 of them for the job. Holes were cut to accept the controls and then wired to 120 VAC receptacles that allowed the customer to plug in their 2 heating elements (top and bottom of vessel), their mixer and their acid dosing pump.

Additional receptacles were added to plug in the mixer and the acid dosing pump. A main on off power switch with circuit breaker and terminal strips were installed and the system wired. Quick disconnects were added for the enc pH sensor connection and dual RTD inputs (one for the temperature controller and the other for the pH controller for automatic temperature compensation. We also provided a connector for dual 4-20 milliamp outputs to send the temperature and pH readings to the customer’s recorder.

Wiring schematics and operating instructions were provided. If you are interested to know more about this system and application – read more here.

In 2014 the customer called and asked us to update these “Tri-controllers” and take advantage of more modern instruments on the market today. Instead of 3 portable systems this time, they wanted two portables and one fixed system that could be mounted near the fume hood with the addition of a remote digital display for the pH portion of the system. They requested that we utilize some of the original equipment and modify the functionality of the system as follows:

The two portable systems retained the original pH and temperature controls while the start up timer was removed (no longer necessary) and a ¼ din data logger was added. The data logger records the pH, temperature, mixer motor speed and torque. Necessary quick disconnects were added for all input signals from the various sensor/transmitters and a panel mount USB connector for downloading the data logger records to a thumb drive when desired.

The permanent system was installed in a 14” x 12” x 8” fiberglass raised face enclosure with the same control scheme but with the addition of a remote Precision Digital panel meter that would be visible at the customer’s eye level.



Front View


Side View









submitted by Wayne Cooke Sr.


Bore seizures are non existent

A  major aluminum extrusion manufacturer was experiencing a high rate failure rate of electric cartridge heaters used in their process.  The heaters were seizing in the “pusher nose” –  the ram used to push the heated billet through the die.  These “nose heaters” must be kept hot to avoid pulling heat from the billet during the extrusion process.

When the heaters seize, they must be drilled out and the heater holes reamed to smooth out the bore which becomes damaged during the drilling and extraction process. When a new heater is inserted they now had a sloppy fit resulting in poor heat transfer from heater to pusher nose with the heaters sometime falling out.  Needless to say, they were experiencing poor performance and high power usage because the heaters had to run hotter and longer to produce the necessary heat required.

The customer wanted a solution and our salesman suggested using a unique cartridge heater offered by one of our principals Dalton Electric Heating Co., Inc. The “split sheath” cartridges expand up to .020″ over their original diameter – enough to take up the slop created by repeated seizures and drill outs of the old conventional design heaters.  The customer placed a small test order for heaters and we waited for the feedback.  So did we solve the problem for the customer?

Yes,  Bore seizures are non existent since switching to the Dalton heaters resulting in:

1. Reduction in replacement cartridge heater purchases
2. Huge savings in machine shop time drilling out seized heaters
3. Reduced Maintenance time pulling rams for service
4. Reduced power consumption.  How much.  We can’t say for sure because the customer does not measure or keep records of electric power usage by department but we typically see savings of upwards of 20%

This is an example of how we may be able to help you with a production or Maintenance problem in your plant.  Please take a moment to watch the video of the benefits of Dalton Electric Heaters.

Incidentally – we have received several subsequent orders for the Dalton split sheath cartridges from a very happy customer.


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