Select valve purge
AssigneeHydro Systems Company
InventorMark D. Dalhart
Life of this patent
Estimating the term…
Abstract
A purge valve for use with a chemical select valve comprises, in a preferred embodiment, an enlarged chamber in the vacuum impelled feed line to the select valve. The chamber is formed by resilient walls, collapsible upon vacuum operation to draw chemical into a venturi line where it is mixed with water and dispensed. The walls do not fully collapse and provide passages for chemical flow. Upon vacuum interruption, the chamber walls expand, returning the chamber to its larger volume and drawing chemical back upstream from common passages in the select valve. Another chemical can then be selected without contamination of the preceding chemical in the common passages.
Claims16
Apparatus for purging common passages of a select valve and including:
- a vacuum impelled feed line connected to said valve;
- an expansible chamber operably disposed in said feed line and at least partially collapsible automatically upon application of a feed vacuum in said line while permitting material flow therethrough;
- said chamber comprising in part a portion of said feed line;
- and
- said chamber being expansible automatically upon termination of said feed vacuum to draw back upstream a volume of material from downstream of said chamber upon expansion of said chamber, whereby said common passages of said select valve are purged upon termination of said feed vacuum.
Apparatus for drawing material back upstream from a vacuum impelled feed passage comprising:
- a vacuum impelled feed passage;
- an expansible chamber disposed in operative communication with said feed passage;
- said chamber being collapsible automatically upon application of a feed vacuum to said feed passage;
- said chamber being expansible automatically upon termination of said feed vacuum and operable to draw a volume of material disposed downstream of said chamber in an upstream direction upon expansion of said chamber.
Apparatus for purging a select valve of remnants of a selected material, said valve of the type having material inlet ports, and common flow passages selectively associated in operative communication with a selected inlet port and with a common outlet to a feed vacuum inducing system operable to create a vacuum in a selected inlet port and material feed line connected thereto, said apparatus comprising:
- a vacuum impelled feed line;
- an expansible chamber operably connected to said feed line;
- said chamber being at least partially collapsible automatically upon application of a feed vacuum thereto and expandable automatically upon termination of said vacuum;
- said chamber, when partially collapsed by said vacuum, defining a reduced volume and, when expanded, defining an increased volume operable to draw back toward said chamber a volume of material downstream thereof upon expansion of said chamber, whereby said common flow passages of said select valve are purged upon termination of said feed vacuum.
A vacuum impelled material feed line for a valve having material passages therein, at least a portion of said feed line having resilient, partially collapsible walls collapsing automatically from a static position to a collapsed position and reducing the volume of said feed line when a feed vacuum is applied thereto while permitting material flow therethrough, and which walls, upon vacuum interruption, expand automatically to said static position from said collapsed position to increase the volume of said feed line and to draw back upstream a volume of material in said feed line downstream of said collapsible line portion upon expansion of said walls, thereby withdrawing a volume of material from material passages in said valve to purge said material passages upon termination of said feed vacuum.
Dependencies are inferred from the claim text.