Control device for a membrane pump

• US 6,344,722 B1
• Filed: 08/08/2000
• Issued: 02/05/2002
• Est. Priority Date: 12/09/1998
• Status: Expired due to Term

• Current Assignee: Abel GmbH & Co. KG.
• Original Assignee: Abel GmbH & Co. KG.
• Inventors: Abel, Goerdt
• Primary Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US09/601,821
• Time in Patent Office: 546 Days
• Field of Search: 318/430-460, 318/560-696, 318/286, 318/282, 318/283, 388/829, 388/831, 417/43, 417/42, 417/22, 417/45
• US Class Current: 318/434
• CPC Class Codes: F04B 2203/0207 Torque
• CPC Class Codes: F04B 2207/044 of the rotational speed of the driving motor
• CPC Class Codes: F04B 49/065 and making use of computers

Abstract

A control device for a diaphragm pump to feed a filter press or similar user unit comprising a three-phase electric driving motor for the pump which is connected to a supply main via a variable-frequency converter, which frequency converter has an analogue output at which a signal will appear which corresponds to the respective motor torque, a standard r.p.m. set-point adjuster to the input of which the actual signal is provided via an inverter and in which a graph is stored which produces an interdependences between the motor torque and the speed such that if the actual-signal rates are small the graph for the speed runs along a constant maximum value and if a preset rate is reached for the actual signal it gradually declines to a minimum value, and an attenuation member for the actual signal.

Claims

1. A control device for a diaphragm pump to feed a filter press, comprising

a three-phase electric driving motor (16) for the pump (18) which is connected to a supply mains via a variable-frequency converter (21), which frequency converter has an analogue output (22) at which a signal will appear which corresponds to the respective motor torque,

a standard r.p.m. set-point adjuster (30) to the input of which the actual signal is provided via an inverter (28) and in which a graph is stored which produces an interdependence between the motor torque and the speed such that if the actual-signal rates are small the graph for the speed runs along a constant maximum value and if a preset rate is reached for the actual signal it gradually declines to a minimum value, and

an attenuation member (23) for the actual signal.

2. The device according to claim 1, characterized in that the declining graph is a straight line.

3. The device according to claim 1, characterized in that a lower speed rate (n_min) is stored in the standard r.p.m. set-point adjuster (30) and the output signal is kept constant when the lower speed rate (n_min) has been reached.

4. The device according claim 1, characterized in that the upper speed rate (n_max) corresponds to a frequency of the frequency converter (21) which is above the mains frequency.

5. The device according to any of claims 1, characterized in that the graph (10) may be programmed and may be adapted to the respective user unit for the pump.