Electronically controlled linear pump drive actuator

Abstract

Electronically controlled linear pump drive actuator for operating a dispensing pump comprising: - a servo motor unit that has: - a stator with a central hollow cavity; - a rotor extending coaxially in the hollow cavity of the stator with a front portion that has a central bore open at the front end; and a rear shaft with a stepped diameter forming a rear extension of the front portion; - respective front and rear support members attached to the front and rear faces of the stator; - a support bearing in the rear support member designed to take and resist substantial axial loads; - a front bearing; and - a position sensor; - a ball screw drive mechanism with a ball screw nut and a ball screw shaft, the ball screw nut is arranged in and attached to the rotor; - a hollow cylinder attached to a front end of the front support member that extends in forward direction; - an actuator member guided for axial movement in the hollow cylinder and has a central rear part fixed to a front end section of the ball screw shaft, and a hollow front part; - a pump plunger adaptor fixed in the hollow front part of the actuator member for releasable attachment of a plunger element of the dispensing pump.

Description

technical field [0001] The present invention relates to an electrically controlled linear pump drive actuator for operating a fluid dispensing pump having generally uniform precision and stability over a wide range of dispensing volumes and loads. Background technique [0002] Precision liquid dispensing pumps are used in many environments where it is necessary to dispense precisely measured quantities of liquid. Examples of such applications are found in the food, cosmetic, pharmaceutical, chemical and battery industries. [0003] A linear liquid dispensing pump is described in US Patent No. 5,312,233. Here, the piston of the pump reciprocates to rotate. Rotation is achieved by a flexible coupling connected to the rotor of the stepper motor. This coupling allows for slight misalignment between the rotor axis and the piston axis. A different example of a device with a servo motor driven pump is described in US Patent Publication 2006 / 0203609. In both prior art designs, ...

AI Technical Summary

Problems solved by technology

As the pump requires more force, this will reduce the precision of the dose adjustment, i.e. resulting in reduced precision

In other words, such actuators cannot be used with the same degree of precision in dispensing pumps having a wide range of viscosities and / or dose volumes

[0014] This means that prior art actuators with the above designs not only have increased length, but also higher rotational inertia and reduced accuracy, the degree of precision depending on the load requirements of the attached dispensing pump

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