Peristaltic Pump For Conveying Liquids In Chemical Apparatus

Abstract

A peristaltic pump for conveying liquids in chemical apparatus having a plurality of plungers. A flexible layer of a material such as polytetrafluorethylene is arranged under tension between the plungers and the hoses containing the liquid to be pumped. The flexible layer of material adapts itself to the level of the surfaces of the individual plungers and, thereby increases the service life of the hoses.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a peristaltic pump for conveying liquids in chemical apparatus, and more particularly to a peristaltic pump having a flexible layer of material which adapts itself to the level of the surfaces of the individual plungers of the pump.

Peristaltic or hose pumps are normally designed in such a manner that one or more of the adjacent hoses containing the liquid to be conveyed are periodically squeezed together by a plurality of mechanically operated plungers arranged one behind the other in the direction of the hoses. As a result of this arrangement, the liquid contained in the hoses is forced along in one direction and sucked through from the other side.

In conventional peristaltic pumps, the hoses are subjected to considerable mechanical wear. For this reason, the hoses in these pumps have to be frequently replaced. Despite the use of high-grade hose material, main areas of wear and tear still occur around the edges of the pump plungers.

SUMMARY OF THE INVENTION

It is the aim of the present invention to provide a peristaltic pump of the aforementioned type, the hose of which has a considerably increased service life.

The underlying problems are solved in accordance with the present invention by providing a flexible layer of material which adapts itself to the level of the individual plunger surfaces and which is secured under tension between the plungers and the hoses.

The arrangement of the present invention assures that the surfaces of the plungers will not press directly upon the hoses. Further, the walls of the hoses follow steadily, rather than jerkily, any changes in the level of the plunger surfaces in cases where the plunger surfaces are arranged at different levels.

Accordingly, it is an object of the present invention to provide a peristaltic pump which avoids by simple means the shortcomings and disadvantages encountered in the prior art.

Another object of present invention is in making readily possible the considerable increase in the surface life of the hoses employed in the peristaltic pump.

BRIEF DESCRIPTION OF THE DRAWING

These and further objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, an embodiment in accordance with the present invention, and wherein:

The sole FIGURE is a sectional elevation view of a peristaltic pump in accordance with the present invention.

DETAILED DESCRIPTION OF THE DRAWING

The sole FIGURE illustrates a peristaltic pump, generally designated by the numeral 1, in which a plurality of plungers 10 are periodically raised and lowered through, for example, a camshaft (not shown) so as to squeeze one or more hoses 2 arranged one behind the other in a bed 3 at different points along the length of hoses. By selectively controlling the movement of the plungers 10, the contents of the hoses 2 are continuously forced along in a desired unilateral direction. The hoses 2 are mounted in hose couplings 4, 5 to which supply and discharge lines 6, 7 are connected.

As shown in the sole FIGURE, the plungers 10 and the hoses 2 are separated by a layer of material 8. One end of the layer 8 is fixed to the pump housing by conventional securing means 9 and the other end of the layer 8 is resiliently anchored to a spring 20. The layer 8 may be made of polytetrafluorethylene reinforced with glass fiber and having a thickness of from 0.2 mm. to 1.5 mm. By the use of this intermediate layer 8, it is possible to lengthen the service life of the hoses 2 from an original service life of 400 hours to a service life of 2,000 hours. In the case of conventional peristaltic pump arrangements, the hoses were already defective by the time that 2,000 hours of service life was reached as a result of the squeezing effect of the plungers.

While I have shown and described one embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a person skilled in the art, and I, therefore, do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as encompassed by the scope of the invention.

Claims

I claim:

1. A peristaltic pump for conveying liquid including a pump housing, at least one hose for conveying the liquid to be pumped and a plurality of plungers operatively associated with said pump housing and adapted to be selectively moved into squeezing engagement with said at least one hose so as to pump the liquid in a desired unilateral direction, characterized in that a flexible layer of material is arranged between the surfaces of said plungers and said at least one hose, wherein one end of said flexible layer is fixedly connected a tone side of the pump housing and the other end of said flexible layer is resiliently connected at the pump housing, whereby the wall of said at least one hose steadily follows any changes in the level of the surfaces of said plungers.

2. A peristaltic pump according to claim 1, wherein said flexible layer consists of polytetrafluorethylene reinforced with glass fiber.

3. A peristaltic pump according to claim 1, wherein said flexible layer has a thickness between about 0.2 and 1.5 mm.

4. A peristaltic pump according to claim 1, wherein said flexible layer consists of polytetrafluorethylene reinforced with glass fiber and has a thickness between about 0.2 to 1.5 mm.

5. A peristaltic pump according to claim 1, wherein said flexible layer is attached at the pump housing under tension.

6. A peristaltic pump according to claim 5, wherein said flexible layer consists of polytetrafluorethylene reinforced with glass fiber and has a thickness between about 0.2 to 1.5 mm.