Reciprocating Positive-Displacement Diaphragm Pump For Medical Use

• US 20120315157A1
• Filed: 12/20/2010
• Published: 12/13/2012
• Est. Priority Date: 12/23/2009
• Status: Active Grant

• Current Assignee: Jean-Denis Rochat
• Original Assignee: Jean-Denis Rochat
• Inventors: Rochat, Jean-Denis
• Granted Patent: US 9,050,408 B2
• Time in Patent Office: Days
• US Class Current: 417/63
• CPC Class Codes: A61M 5/14224 Diaphragm type
• CPC Class Codes: F04B 35/045 using solenoids
• CPC Class Codes: F04B 43/04 Pumps having electric drive

Abstract

Reciprocating positive-displacement diaphragm pump (1) intended for liquids and for medical use, has a driving part (10) within which there are an electromagnetic actuator (11), incorporating at least one coil (12) and activating a piston (14) of a moving member (15) capable of cyclic linear motion. The pump comprises a pump body (20) within which there is a pre-loaded diaphragm (22) able to undergo a translational movement by elastic deformation from a normal rest position to an adjacent position through the transmission of the work from a piston (14). It incorporates a device (30) for detecting out-of-tolerance variations in the intensity of the supply current by measurements (33), a device (40) for continuously measuring the position of the moving member (15) and devices (30, 45) for processing and analyzing the measurements, which are able to generate at least one malfunctioning alarm signal (35) indicating the detection of at least one malfunction of the pump.

Claims

1. Reciprocating positive-displacement diaphragm pump intended for pumping liquids in the context of medical use, comprising, on the one hand, a driving part within which there are:

an electromagnetic actuator formed of a magnetic circuit incorporating at least one coil and activating a piston of a moving member capable of cyclic linear motion,

and, on the other hand, a removable pump body within which there are;

a preloaded diaphragm able to undergo a translational movement by elastic deformation from a normal rest position to an adjacent position through the transmission of work from the piston, a first non-return valve positioned upstream of the said diaphragm to close the internal end of an inlet pipe at the inlet to the pump body and prevent any delivery of liquid, a second non-return valve positioned downstream of the diaphragm, one of the valves also being intended to prevent any gravity flow through a delivery pipe situated at the outlet of the said pump body,

the pump further comprises means for detecting, in each cycle, out-of-tolerance variations in the intensity of the supply current that powers the actuator from measurements of this current,

wherein it also comprises means for continuously taking measurements of the instantaneous position of the moving member along its line of travel and means for processing and analyzing the said measurements which are able to generate at least one alarm signal signifying that at least one malfunctioning of the pump has been detected.

2. Pump according to claim 1, wherein it further comprises means, controlled by at least one of the said processing and analysis means, to provide feedback control of the position of the moving member along the entire length of its line of travel.

3. Pump according to claim 1, wherein it comprises a compensation member which delivers, to the diaphragm, a force of an intensity slightly greater than the sum of the weight of the moving part and of the friction forces associated with the moving member.

4. Pump according to claim 1, wherein the preload applied to the diaphragm is enough to be able to draw in a new volume of liquid to be pumped and to return the moving member to the rest position.

5. Pump according to claim 1, wherein the means that can be used to measure the instantaneous position of the moving member consists of electro-optical means comprising an emitter which generates a flow of energy and a receiver that supplies a signal in response, the intensity of which varies as a function of the position of the moving member along its stroke.

6. Pump according to claim 5, wherein the variation in the intensity of the said response signal is obtained by the movement of a shutter (18), associated with the moving member, that can become interposed between the emitter and the receiver in order to influence the amount of energy received by the receiver.

7. Pump according to claim 1, wherein the pump body consists of a removable single-use cassette.

8. Pump according to claim 1, wherein the magnetic circuit comprises a pot made of ferromagnetic material encircling the said coil in order to channel the magnetic flux thereof, and a pole piece secured to the piston and which with the said pot determines an air gap the thickness of which varies according to the position of the moving member along its line of travel.

9. Pump according to claim 1, wherein the piston is guided in its travel by non-magnetic bearings, and in that this piston and these bearings are made of materials with low coefficients of friction, such as ceramic and hard metal.

10. Pump according to claim 1, wherein the electromagnetic actuator comprises a rotary motor incorporating means of converting a rotary movement into a cyclic linear movement applied to the piston.

11. Pump according to claim 1, wherein the electromagnetic actuator comprises a linear or rotary stepping motor, and in that the said means that can be used to measure the instantaneous position of the moving member comprise means of counting the steps of the said motor.