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Reciprocating diaphragm pump

Reciprocating diaphragm pump description/claims

The present invention relates to a reciprocating diaphragm pump in accordance with the preamble of claim 1.

Reciprocating diaphragm pumps are known according to the state of the art.

A reciprocating diaphragm pump comprises, typically, a series of pistons housed inside cylinders which are arranged adjacent to one another and define piston stroke work chambers. The pump also comprises pumping work chambers intended to be closed and opened by means of intake valves, on the intake side, and to be opened and closed by means of delivery valves, on the delivery side.

The pumping work chambers and the piston stroke work chambers are separated from each other by diaphragms which receive, transmitted to them via the fluid present inside the piston stroke work chambers, the work performed by the stroke of the piston during its reciprocating movement inside the cylinder.

In order to simplify the connections between the pumping work chambers, piston stroke work chambers and the diaphragms, the pumping chambers are arranged axially aligned with the piston stroke chambers.

This relative arrangement of the pumping and piston stroke work chambers has, however, certain drawbacks. It must be pointed out, in fact, that the cross-sectional dimension of the pumping work chambers and the piston stroke work chambers in the region of the diaphragms are significantly greater than the cross-sectional dimension of the pistons. For this reason, the pumping work chambers may be arranged in the configuration axially aligned with the respective piston stroke work chambers only if the cylinders are kept sufficiently spaced from each other.

Therefore, an increase in the number of cylinders and associated diaphragms and/or an increase in the cross-section of the diaphragms requires a corresponding increase in the distance between the cylinders or the centre distance of the pump. On the other hand, an increase in the distance between the cylinders requires a corresponding adaptation of the piston actuating systems, with a consequent increase in the costs, and results in an increase in the dimensions of the end of the pump and the overall dimensions of the pump.

A solution to this problem has been proposed in the document EP 380 922 which describes a reciprocating diaphragm pump having a plurality of cylinders arranged adjacent to one another in a row so as to define work chambers for the stroke of an associated piston.

In accordance with this prior art, the pumping work chambers associated with the adjacent piston stroke work chambers are arranged on different sides of the row of cylinders. In particular, in the case of a three-cylinder pump, the pumping work chamber associated with the central chamber is arranged as an extension of the central cylinder, while the pumping chambers associated with the two side cylinders are arranged laterally with respect to the axis of the central cylinder. The aforementioned solution, while reducing the problems encountered in the previously known pumps, has significant drawbacks and gives rise to a series of problems relating to the interchangeability of the pistons.

In fact, the particular arrangement of the diaphragms proposed in the document EP 380 922 requires the use of pistons with different lengths, with the consequent impossibility of interchanging the pistons, and creates different spaces which are prejudicial for the two lateral cylinders in relation to the central cylinder, with a consequent overall imbalance of the pump. It must also be noted that the presence of pumping chambers and associated lateral diaphragms produces stresses and therefore vibrations in the direction transverse to the movement of the pistons.

From above, it is clear that ther's a need to provide a reciprocating pump with in-line cylinders which allows the distance between the cylinders to be kept constant and which allows interchangeability of the pistons with an increase in the size of the diaphragms and/or the number of cylinders.

The object of the present invention is therefore to provide a reciprocating pump which has structural and functional characteristics such as to satisfy the abovementioned requirements and overcome at the same time the drawbacks encountered with reference to the prior art.

This object is achieved by a reciprocating pump according to claim 1.

Further characteristic features and advantages of the reciprocating pump according to the present invention will emerge from the description below of a preferred example of embodiment, provided by way of a non-limiting example, with reference to the accompanying figures in which:

FIG. 1 shows a partially sectioned, schematic, perspective view of a reciprocating pump according to the invention;

FIG. 2 shows a front view of the reciprocating pump according to FIG. 1;

FIG. 3 shows a cross-sectional side view of the reciprocating pump of FIG. 1 along the cross-sectional line III-III of FIG. 2; and

FIG. 4 shows a cross-sectional view of the front part of the reciprocating pump of FIG. 1 along the cross-sectional line IV-IV of FIG. 3.

• Provisional Patent
• Utility Patent

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