FR2480362A1 - Electromagnetic pump for liquid - has magnet core connected via insulator to move diaphragm of variable volume compression chamber - Google Patents

Abstract

The electromagnetic pump includes an inlet and an outlet pipe connected to a compression chamber via respective non-return valves. The volume of the compression chamber is determined by the position of the elastic membrane which forms a seal between the chamber and the operating electromagnet. The electromagnet includes coils and a moving core, the core being attached via a non-conducting tapered rod to the pump membrane. When the electromagnet is operated the core moves, also moving the membrane to operate the pump. When the current to the electromagnet is interrupted, the core is moved in the opposite axial direction by a return spring. The non-conducting tapered rod ensures that there is no electrical contact between the liquid and the electromagnet assembly.

Description

An electromagnetic pump is known comprising a body, defining a path for liquid to flow from a suction pipe to a delivery pipe. An electromagnet alternately changes the pressure in a portion of the path, thereby causing suction and discharge.

 Part of the path for the liquid is formed by the central passage of the electromagnet coil, where the magnetic core of the latter moves. This thus saves resources and a pump is obtained having a symmetry of revolution which appears a priori favorable.

However, it has now been recognized that this arrangement is the source of two main drawbacks. The proximity of the coil and the liquid causes the latter to heat up.

During cooling, crystallizations occur which prevent or hinder the subsequent movement of the core in the jacket delimiting the central passage. The characteristics of the pump become less good. This cannot be remedied by increasing the thickness of the jacket in order to further isolate the inner wall from the coil, without thereby reducing the efficiency of the electromagnet. In the event of a current leak, it passes into the often conductive liquid. This is an unacceptable danger for a pump, intended for an appliance for the use of the general public.

The pump according to the invention overcomes these drawbacks.

She is safer. It retains its characteristics over time.

The subject of the invention is a pump comprising a body, with suction and discharge pipes, defining a path for liquid to be drained, dw means by electromagnet for alternately modifying the pressure prevailing on at least a portion of said path, characterized in that the core of the electromagnet is outside said path.

As the liquid does not pass any more in the jacket where the core moves, no deposit can come to hinder in the long run the displacement The path for the liquid can be far from the reel so that it is easy to interpose between them electrical and / or thermal insulation.

In the accompanying drawing given only by way of example
the single figure is a sectional view of a pump according to the invention.

 The pump comprises a coil 1 of an electromagnet in the central jacketed passage from which a core 2 of magnetic steel moves. The coil 1 is placed in an envelope 3.

The lower part of the carcass 4 of the coil 1 rests on a washer 5 surrounding a flow ring 6. The whole rests on a flange 7 of electrically and thermally non-conductive material.

 The underside of the flange 7 wedges an elastic membrane 8 on a pump body 9 of electrically and thermally non-conductive material delimiting a path for liquid to be discharged from a suction pipe 10 with valve 11 to a delivery pipe 12 with valve 13. The membrane 8 delimits part of this path.

 The membrane 8 is secured to the core 2 by a spacer 14 made of a material which is not electrically conductive and by a head 16 of screws made of a material which is also non-conductive. The core 2 is recalled by a spring 15.

As the core 2 is outside the body 9, even if a current leak occurs, it does not propagate in the liquid which passes through the body 9.

 As the core 2 is outside the body 9, it is possible to separate the body 9 and the coil 1 from one another; the heat supplied by the coil propagates less in the liquid as much as the flap 7, the spacer 14, the tette 16 and the body itself are poor conductors of heat.

 Of course, the invention applies not only to diaphragm pumps, but also to positive displacement pumps in general and in particular to those with piston.

Claims (5)

1. Pump comprising a body, with suction and discharge pipes, defining a path for the liquid to be flowed, and means by electromagnet for alternately modifying the pressure which prevails over at least a portion of said path, characterized in that that the core of the electromagnet is outside said path.  2. Pump according to claim l, characterized in that the core is integral with a deformable membrane delimiting part of the path. 3. Pump according to claim l or 2, characterized by means for electrically isolating the core from the liquid traversing the path. 4. Pump according to claim 3, characterized in that said means comprise a part made of a material which does not conduct electricity inserted between the membrane and the core. 5. Pump according to one of claims l to 4 charac terized by means for thermally isolating the coil of the electromagnet from the liquid flowing on the path.