Customer Type: Clean Room operator
Application: Simulating a 4-20 milliamp signal
Solution: Druck's DPI 620G Calibrator
Druck design and manufacture pressure calibrators, controllers, indicators and pressure sensors. All these products begin with raw silicon which is processed in a state-of-the-art clean room. Druck’s new clean room facility, installed and maintained by Precision Cleanrooms, is critical to the manufacturing processes.
A clean room is a controlled environment that is designed to maintain extremely low levels of pollutants such as dust, airborne microbes, aerosol particles, and chemical vapours.
Druck’s clean room, creates silicon wafer that is cut into individual Die, which is then fixed into modules. Once through this process, the modules are then integrated into finished products such as Druck’s pressure sensors and test and calibration equipment, which include Portable Calibrators, Pressure Controllers and Air Data Test Sets.
Precision Cleanrooms specialise in the design and construction of high quality clean rooms whilst providing ongoing support and maintenance of the facility, ensuring optimal production output for their customers.
Linked to Druck’s clean room is a tank containing deionised water which feeds the process for creating Die. Deionised water is required as part of the manufacturing processes to keep the clean room operating, enabling the silicon to be cleaned at each stage of the production process.
On the top of the tank is a telemetry system which enables automated remote monitoring, collecting measurements and important data from within the tank. This data is transmitted back to the control room which ensures performance is maintained to the required specification.
A level sensor is fitted within the tank and is monitored by the telemetry system to detect the water level, ensuring specified minimum and maximum levels are not exceeded. The level sensors have a 4 to 20 milliamp current loop output signal and determine the water level by measuring the hydrostatic pressure of the water pushing down on the bottom of the tank.
An issue occurred where the tank’s telemetry system alerted the Druck team employed in the clean room of a water leak within the tank. Upon investigation the level sensor had failed and required a replacement sensor which had a 3-week lead time for delivery.
Precision Cleanrooms needed a solution to ensure that there was no disruption to the productivity of Druck’s clean room. If the water being fed from the tank is switched off for more than 24 hours the system’s pipework would require sanitisation - which takes approximately two days, leading to a loss of production. Once the water feed has been turned off, it also takes a further two months for the water purification system to fully stabilise, which could mean further losses of production output.
Druck's solution and added value
Druck provided Precision Cleanrooms with a DPI 620G-IS-L Genii Intrinsically Safe Multifunction Calibrator, allowing them to simulate the 4-20 milliamp signal, the level sensor should have been providing.
Picture 1: DPI 620G
Druck’s DPI 620G provides simultaneous measurement and source capabilities for the setup, testing and calibration of electrical, frequency, pressure and temperature devices in measurement and control applications.
The DPI 620G was used to hold the value at a fixed output (simulating the role of the sensor) which meant the clean room could continue with daily operations, without risk of danger to personnel, equipment, silicon failures or loss of production. This action saved Druck potential production losses amounting to $750,000.
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