| 摘要 |
<p>A method for controlling the discharge pressure of an engine-driven centrifugal pump in a system is disclosed. The system includes the engine having an idle speed Si, the pump being driven by the engine, an intake line coupled to the pump for receiving a liquid, a discharge line coupled to the pump for discharging the liquid, an internal pressure sensor in the discharge line sensing an actual internal pressure Pa in the discharge line, a relief valve in the discharge line, the relief valve being actuable in a first direction away from a fully closed initial condition, and a controller operatively connected to the engine, the internal pressure sensor and the relief valve, for varying a speed of the engine, and a condition of the relief valve. The method of controlling the discharge pressure of an engine-driven centrifugal pump comprises a) selecting a desired internal pressure Pd for the discharge line, b) operating the engine to drive the pump and generate pressure in the discharge line, c) increasing engine speed if Pa < Pd while maintaining the relief valve in the fully closed initial condition, d) decreasing engine speed if Pa > Pd and the engine speed is greater than Si, while maintaining the relief valve in the fully closed condition, e) opening the relief valve if Pa > Pd and the engine speed is equal to or less than Si without adjusting the engine speed; and f) closing the relief valve if Pa < Pd and the engine speed is less than or equal to Si; and g) repeating steps c) through f).</p> |
