Quicker testing of toilet pans
| Mitsubishi Electric | visit website |
An automated test station developed by toilet pan manufacturer JSI Leaches in Stoke-on-Trent is claimed to be five times faster than the previous arrangement, allowing it to vacuum test all pans rather than only a sample few. The control system is based on a small PLC which performs the basic sequencing of operations, and a human-machine interface (HMI) from which the operator controls the test.
The HMI is a relatively simple unit, an E100 from Mitsubishi Electric, but it gives the operator local autonomy to make adjustments to the testing times if required. Primarily it highlights the pass and fail results to the operator, but it also automatically collates tests results and forwards them for preparation of production management reports. The PLC performs all the automated functions and is also a Mitsubishi product.
Toilet pans are produced by moulding, after which they are fired and finally glazed. The test follows the glazing stage and is designed to weed out any pans that could leak once in use, either because the moulding is porous or because the glazing has cracked, which can occur in some impossible-to-see recess of the trap. In the test station, the operator clamps and seals a blanking plate over the toilet bowl's top opening and connects a vacuum hose to the bottom outlet, then the PLC takes over for the automated testing.
Vacuum is drawn within the pan to a defined top pressure, with a pressure sensor alerting the PLC when the set point is reached. The PLC than activates a solenoid valve to isolate the pump, which runs continuously as it serves several test stations simultaneously. The vacuum pressure is monitored minutely for the next 30 seconds. If it holds steady, the pan passes; if it falls below a second set point, it fails. Because of the HMI's controllability, the operator can extend or rerun the test on any pan that may be a borderline case.
JSI Leaches is installing multiple stations in all five of its UK plants and in its Bulgarian facilities.
30 May 2006
| Mitsubishi Electric | visit website |
