METHOD FOR DETERMINING THE POSITION OF THE DIAPHRAGM OF AN ELECTRIC-MOTOR-DRIVEN DIAPHRAGM PUMP

Abstract

A position detection device determines the position of the diaphragm or the drive piston of an electric-motor-driven diaphragm pump, in particular, by detecting the upper and lower reversal point (Po, Pu) in the movement curve of the diaphragm of the diaphragm pump. A diaphragm is actuated by a drive connecting rod to close a conveying chamber with valves provided on an inlet and outlet side. The volume can be changed between a minimum and maximum volume. A rotational movement of an electric motor, with a rotor, is converted into the actuation movement of the drive connecting rod via the effect of the eccentrics. The position detection device detects the load curve of the diaphragm pump during the movement of the diaphragm. An evaluation device determines at least the position of the upper and lower reversal point of the diaphragm from the load curve.

Claims

1.-10. (canceled)

11. A position detection device for determining the position of a diaphragm or a drive piston of an electric-motor-driven diaphragm pump, in particular for detecting upper and lower reversal point in the movement sequence of a diaphragm of a diaphragm pump comprising: the detection device operated in an electric-motor-driven manner via eccentric elements, the diaphragm is actuated by a drive connecting rod to close a feed chamber, with valve elements on the inlet and outlet side, the volume can be changed between a minimum and maximum volume through the action of the eccentric elements; a rotary motion of the electric motor, with a rotor, is converted into an actuating motion of the drive connecting rod; and the position detection device detecting a load curve of the diaphragm pump during the movement of the diaphragm and has an evaluation device determining at least the position of the upper and lower reversal point of the diaphragm from the load curve.

12. The position detection device according to claim 11, wherein the detection device detects a torque progression curve of the diaphragm pump during a complete up and down motion of the diaphragm.

13. The position detection device according to claim 11, wherein measuring device detects the position of the rotor of the electric motor.

14. The position detection device according to claim 13, wherein the measurement for detecting the rotor position is carried out by multiple position sensors of the rotor of the electric motor, in particular by Hall sensors, and more preferably, by an angle gage for detecting the current rotation angle.

15. The position detection device according to claim 13, wherein an evaluation device cumulatively determines the position of the diaphragm, in particular, the upper and lower reversal point of the diaphragm, the determination is based on at least the load curve and the relative torque maxima and/or torque minima and based on the position of the rotor that is detected in parallel.

16. A diaphragm pump embodied with a position detection device according to claim 11.

17. A method for determining the position of a diaphragm or a drive piston of an electric-motor-driven diaphragm pump, in particular, for detecting an upper and lower reversal point in a movement sequence of the diaphragm of the diaphragm pump that is operated in an electric-motor-driven manner via eccentric elements, comprising: actuating the diaphragm by a drive connecting rod, closing a feed chamber, with valve elements on the inlet and outlet side; changing volume between a minimum and maximum volume through action of the eccentric elements; converting a rotary motion of an electric motor, with a rotor, into the actuating motion of the drive connecting rod; and carrying out a position determination based on at least the detection of a load curve and a relative torque maxima and/or torque minima.

18. The method according to claim 17 with a position detection device according to claim 11.

19. The method according to claim 17, wherein based on the data set of the load curve together with the position of the rotor, an evaluation device cumulatively determines the position of the diaphragm, preferably the upper and lower reversal point of the diaphragm.

20. The method according to claim 17, wherein the drive motor is an inverter-fed DC motor and the load curve is determined indirectly from a base-point current measurement of the motor, the measurement of the sum current is preferably taken at the base point or feed point of an inverter bridge of the inverter.

Description

DRAWINGS

[0025] In the drawings:

[0026] FIG. 1 is a schematic view of a flowchart, which shows the steps for determining the turning points according to the disclosure.

[0027] The disclosure will be described in greater detail below based on an exemplary embodiment with reference to FIG. 1.

DETAILED DESCRIPTION

[0028] FIG. 1 shows a flowchart with two processes running in parallel. During the entire process of the determination of the turning points, a speed control of the motor that drives the diaphragm pump is carried out. The right side of the flowchart shows how the detection of the upper and lower reversal point (turning points) is carried out.

[0029] The position detection of the reversal points of the diaphragm is carried out based on the rotor position and the motor current (load curve) using position sensors and an angle gage. The limit value of the corresponding motor current is needed. Thus, this changes cyclically with each rotation until it reaches a maximum value.

[0030] After the determination of the limit value by means of the measured current, first the stored values for the angular sum and a value counter are reset to zero. A new mechanical rotation can begin or, stated more precisely, a check is performed as to whether a new mechanical rotation has begun. If this is the case, then the evaluation device checks whether the current now being detected is greater than the limit value. If this is the case, then the angular sum is determined by adding the currently determined angle to the stored value of the angular sum and increases the count of the value counter by 1. The limit value used as the basis for comparison is preferably the heavily filtered motor current. The motor current is then compared to this limit value and once the motor current is less than or equal to the limit value, the turning point has been reached. In principle, the angle gage is a memory, which, in each time interval (e.g. 100 ps), is increased by the distance that the rotor has traveled based on its current speed. In principle, angular distances are always added in this case, with these angular distances being expressed in the unit “degrees.”

[0031] The process is carried out until the iterative query determines that the mechanical rotation has ended. Then the turning point can be determined from the angular sum and the value counter.

[0032] The embodiment of the disclosure is not limited to the preferred exemplary embodiments disclosed above. On the contrary, there are a number of conceivable variants that make use of the presented embodiment, even in fundamentally different embodiments.

[0033] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.