Valois

Societe Technique De Pulverisation - Step Sa

Patrick Di Giovanni

Jean-Pierre Lina

Claude Jouillat

Michel Brunet

Herve Pennaneac'h

Some precompression pumps currently used for spraying a liquid include a non-return valve formed by a gasket (3) held captive between the base of the pump body (1) and a sleeve (2). This non-return valve determines the extent to which the pump chamber (19) is isolated from or put into communication with a supply of liquid, as a function of whether the gasket (3) bears against the base of the pump body (1) or against the sleeve (2), closing a central hole through the pump body or being held off a central hole through the sleeve. In order to make valve operation more reproducible the present valve has the following features: the base of the pump body (1) is in the form of a cup (18) of small slope; the side wall (28) of the sleeve (2) flares from the end (26) of the sleeve (2) and has a local swelling (27), with the side wall (28) being of reduced thickness on either side of the swelling (27 ); and the end (26) of the sleeve (2) includes a tongue (25) and two ribs (2b), the tongue (25) and the ribs (2b) extend from the side wall (28) of the sleeve (2) all they way to its central hole (2a), the tongue (25) is diametrically opposite the swelling (27) and it is thickest adjacent to the central hole (3a), the ribs (2b) are disposed symmetrically about the diameter passing through the swelling (27) and the tongue (25) such that each of them forms an acute angle with the diameter on either side of the swelling (27).

Non-return valve for admitting a liquid to be sprayed into a pump

A precompression metering pump of the prior art which is otherwise particularly advantageous, is nevertheless difficult to prime because of the high degree of compressibility of the air it initially contains in its pump chamber. The present invention improves this aspect of metering pump operations. It consists in providing additional resilient means (20) and at least one cylindrical part (10) level with the conventional outlet non-return valve of the pump and constituting a second outlet non-return valve. In a particular embodiment, the resilient means and the cylindrical part are received one above the other in the outlet channel (33) of the pump actuator rod (31). To do this, they bear respectively against a choking step (32) in the form of a lug and a shoulder (34) presented by said channel. In normal operation, the differential piston (4) of the pump moves out of the way so that operation takes place as in a prior art precompression metering pump. However, when priming, by pushing the actuator rod (31) fully home, as is made possible by the invention, the part (10) is moved away from the choking step (32). This improvement thus enables the air which was initially contained in the pump chamber (23) to be expelled to the atmosphere.

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Elbeuf, France

Patrick Di Giovanni