Manufacturing Pressure CellsNov 14th, 2018
Ready for despatch – Geosense technician Clare Armitage makes final checks to a batch of Total Earth Pressure Cells - Model VWTPC-4000.
In Geosense’s manufacturing facility, two stainless steel plates are welded around their periphery with the narrow gap between the plates filled with hydraulic fluid. This order required a low pressure of 69kPa (10psi).
Production Manager John Fordham said: “It is crucial that the hydraulic fluid is completely free of air and so the process includes the use of a special de-aerator. Any air in the fluid could affect the accuracy of the cells”.
When installed, external pressure on the outside surfaces of the cell squeezes the two plates together creating an internal fluid pressure. A length of stainless steel tube connects the cell to a pressure transducer which converts the fluid pressure into an electrical signal which can be directly read-out or transmitted to a data logging system.