Feeding sludge at increasing counter-pressure by twin pumps - with transversed feeder including slider controlled to maximise total pump efficiency

摘要

Reducing amts. of liq., esp. sewage sludge travelling from an inlet (1) to a filter press (4) are measured by a meter (8) in the main flow conduit (8) and communicated to a controller (10). The conduit is split into two parallel connector tubes (11, 12) each including an identical rotary pump (6, 7). A transverse feeder (16) extends from after the first pump (6) to before the second pump (7) and includes a slider (18) kept closed for large flow rates, but opening when the rate drops to about 45% of max. possible value. When the slider is closed, two automatically operating non-return valves (13, 14) open, isolating the transverse feeder from sludge flow. Pressure readings ahead of the press are measured (9) and via controller (9) ensure the slider (18) is opened when one of the rotary pumps is approaching the max. rated pressure. ADVANTAGE - Max. pressure on individual pumps is halved, reducing gap losses and ensuring longer operation in the high efficiency field, where rotor wear and power consumption are reduced.