The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 05, 1990
Filed:
Jun. 02, 1989
Michel Brunet, Sainte Colombe La Commanderie, FR;
Patrick Di Giovanni, Elbeuf, FR;
Claude Jouillat, Montigny Sur Avre, FR;
Jean-Pierre Lina, Le Neubourg, FR;
Herve Pennaneac'h, Verneuil-Sur-Avre, FR;
Societe Technique de Pulverisation - STEP SA, Paris, FR;
Abstract
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.