FR2527700A1 - MEMBRANE METERING PUMP WITH TWO RETAINING VALVES - Google Patents

Abstract

The diaphragm dosing pump has two ball non-return valves (3, 4) both in the intake line and in the delivery line (1 and 2, respectively), which are connected in pairs in series with axis vertical. The balls acting in concert with frustum-shaped sealing seats are, like the seats, made of corrosion-resistant material. The valves (3, 4) are closed simply by gravity, so that no return springs exposed to corrosion, as are provided in the case of known non-return valves, are needed. Owing to the series connection of the valves (3, 4) in each line (1, 2) perfect sealing can be ensured even if one of the balls does not lie tightly on its seat due to solid particles.

Description

MEMBRANE DOSING PUMP WITH TWO RETAINING VALVES.

The present invention relates to a diaphragm metering pump, provided with two check valves.

The dosing pumps, used for dosing liquids, are provided with a suction valve and a discharge valve, which are check valves, constrained by suitable springs.

 It is known that these pumps are also used for dosing corrosive liquids, such as liquid detergents, solvents, anti-algae substances (for swimming pools), sodium hypochlorite (for disinfecting swimming pool water), or similar substances.

In these cases, the liquid can attack and corrode the return springs which cooperate with the check valves, and deteriorate the pump.

Even if these check valves are provided with a vertical axis such that the shutters fall into the respective seats by simple gravity, making it possible to eliminate the return springs, proper operation of the pump is not possible.

Indeed, solid particles in suspension in the transported liquid can be deposited on the valve seats, and can affect the sealing of the latter.

The present invention proposes to eliminate the drawbacks mentioned above, by producing a metering pump 9 membrane, usable for corrosive liquids.

One of the aims of the present invention consists in producing a diaphragm metering pump, the valves of which, arranged on the suction and discharge pipes, operate regularly, even in the presence of corrosive liquids and / or containing solid particles in suspension. .

This object is achieved by a diaphragm metering pump according to the invention, characterized in that it comprises, either on the suction pipe or on the delivery pipe, at least two ball check valves, arranged in series and which is closed by the force of gravity acting on the balls.

Other characteristics and advantages of the diaphragm metering pump according to the present invention will emerge from the description of a preferred embodiment of this pump, and from the attached drawing in which FIG. 1 is a view in vertical section of the said pump, and FIG. 2 is a detailed view showing the flow variator mechanism applied to said pump.

With reference to the figures, the diaphragm metering pump described is equipped with two double check valves 3 and 4 mounted respectively on the suction line 1, and on the discharge line 2.

These valves are formed by two valve bodies arranged in series, their vertical axes being aligned and provided with frustoconical seats and free ball shutters, made of an anti-corrosion material.

The liquid is drawn in and discharged by a membrane 5, which is in a vertical plane and divides a circular chamber 6 into two parts, one of which communicates with the pipe 7 connecting the valve bodies 3 and 4.

The diaphragm is driven in an alternating movement by means of a piston 8, the head of which bears against a cam 9, rotating at a constant angular speed.

The head 1 (3 of the piston 8 is held in abutment against the edge of said cam 9 by means of a helical spring 11, disposed between the cylindrical body 12 forming the guide of the piston and a plate 13, fixed to one end of this latest.

The mechanism for adjusting the discharge is formed by a micrometric screw 14, coupled to said plate, this screw being able to be supported by its ex-.

free end on a stop 15, integral with the axis of the cam rotation shaft 9.

In practice, the valves 3 and 4 are supported on their seats by the effect of the force of gravity and can therefore operate without the use of return springs.

In addition, said valves are two in number on each pipe, respectively for suction and discharge, so as to guarantee safe operation of the porn, even when a ball valve does not return to its closed position, because impurities or foreign bodies.

Thanks to this solution, the self-priming pump can transfer different liquids from the bottom up.

Indeed, even if an impurity particle is on the seat of a valve, said particle is sucked by the current which is created due to the continuous operation of the pump.

The upper part of the valve bodies is of course provided with an oval hole, to allow the passage of the liquid upwards.

Claims (5)

Claims 1. Diaphragm metering pump, characterized in that it comprises at least two ball check valves (3, 4) mounted respectively on the suction pipe (1) and on the discharge pipe (2), arranged in series and operating on closing by the effect of the force of gravity. 2. Pump according to claim 1, characterized in that said check valves (3, 4) are formed by two valve bodies in series, of verticalyet axis provided with frustoconical seats and free shutters, made of an anti material -corrosive. 3. Pump according to any one of the preceding claims, characterized in that, in said pump, the suction and the delivery of the liquid are carried out by a membrane (5) arranged in a vertical plane, said membrane being driven by an alternating movement by means of a piston 8) whose head is supported on a rotary cam (9) of constant angular speed. 4. Pump according to any one of the preceding claims, characterized in that the head (10) of said piston (9) is held in abutment against the edge of said cam (9) by means of a helical spring (11) disposed between a cylindrical tubular body (12), forming the guide of said piston, and a plate (13) fixed to the end of the latter. 5. Pump according to any one of the preceding claims, characterized in that, in said pump, the mechanism for adjusting the flow rate is formed by a micrometric screw (14) connected to said plate (13) ,. the free end of which bears against a stop integral with the axis of rotation (16) of said cam (9).