The instrument air and lubricating oil pressures of the diaphragm pump are interlocked with the main motor. The oil injection and discharge valves for the propulsion fluid are air-sealed valves, requiring a constant air pressure. The minimum operating pressure of both valves is no less than 0.4 MPa, so the instrument air pressure is generally maintained above 0.15 MPa. Even after the pump stops, the instrument air pressure is maintained to prevent insufficient or excessive liquid in the propulsion chamber. The air supplied to the valves is filtered and atomized.
During operation, the lubricating oil pressure should not be lower than the pressure interlock value (0.15 MPa), and the pressure difference of the lubricating oil outlet filter should not be too large. The steel ball in the lubricating oil flow sight glass should be at the upper limit position. Adjustments to this flow rate should not be too large to avoid a rapid pressure drop due to excessive instantaneous flow, which could trigger the interlock and cause a trip.
Through these process improvements and mastery of operational points, a stable operating environment is maintained for the diaphragm pump. In over a year of operation, there has only been one trip due to an electrical fault, achieving long-term, safe, and efficient operation.
