US 4,967,940 AGranted

Method and apparatus for precision squeeze tube valving, pumping and dispensing of work fluid(s)

AssigneeMinnesota Mining and Manufacturing Company

InventorsRussell E. Blette, John O. Roeser

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Abstract

Presented is a method and apparatus for precision control of work fluids in a squeezable tube that has no surge of work material during the shut off closing of the tube which is accomplished by a compensator moving simultaneously and oppositely to the shut off member movement, each of the compensator and the shut off member having different stroke lengths and tube engagable surface areas which effectively keep the internal volume of the tube the same. The method and apparatus are useful standing alone, in coordination with precision positive displacement pumping under computer control which is also presented, and as a part of sequential or simultaneous movement of a valve/pump dispensing head coordinated with a stationary or movable work piece to provide exceedingly fine control dispensing. Suckback between dispensing shots is coordinated with shut off and movements of inlet, outlet and dispensing members to afford operator programmable dispensing with precision and without drip.

Claims25

Dependent claims

A high precision positive displacement squeeze tube pump apparatus comprising:

(a) tube means having first and second spaced end means and characterized as:
(i) being hollow and having walls formed of resilient material,
(ii) forming a closed pathway for flow of a flowable work material therethrough,
(iii) having its first end associated with a source of flowable work material, and
(iv) having its second end associated with means for receiving said flowable work material after passage through said tube means, and
(b) flow control means for controlling the flow of work material through said tube means, said flow control means being characterized as comprising:
(i) first, second, third and fourth cooperating spaced tube squeezing means located intermediate said first and second spaced end means of said tube means and engagable with said tube means for effecting control of the flow of work material therethrough,
(ii) said first tube squeezing means having open and closed positions, being movable between said open and closed positions, and located near said first end means to control ingress of work material to said tube means,
(iii) said second tube squeezing means being spaced from said first tube squeezing means, having open and closed positions, and being movable between said open and closed positions for controlling exiting of said flowable work material from said tube means,
(iv) said third tube squeezing means being associated with said tube means intermediate said first and second tube squeezing means, being movable toward and away from squeezing relation of said tube means, and when moving toward said tube means being operable to displacingly force work material from said tube means, and
(iv) fourth tube squeezing means operable in coordination with said second tube squeezing means to compensate for displacement of work material through said tube means when said second tube squeezing means moves between its open and closed positions,
whereby the volume of material in said tube means that is displaced from said tube means will be primarily controlled by movement of said third tube squeezing means.

9 more elements

The apparatus set forth in claim 12 wherein the said second tube squeezing means has a first length of stroke of movement toward and away from squeezing said tube means and said fourth tube squeezing means has a second length of stroke of movement toward and away from squeezing said tube means, adjustment means associated with said link means for adjusting said second length of stroke of movement, whereby operator adjustment of said adjustment means is operable to cause the coordinated relative movement of said fourth tube squeezing means to said second tube squeezing means to be adjusted to provide adjustable suck back of said flowable work material.

The method of precision positive displacement pumping of a flowable work material from a source operable to cause the flowable work material to move to a pump means having a dispensing outlet and having a flexible tube means having an inlet end and an outlet end and having an inlet movable surface, a displacement movable surface, an outlet movable surface and a compensator movable surface each for pinchingly engaging and disengaging said flexible tube means between the inlet end and outlet end, said compensator movable surface being larger than said outlet movable surface comprising the steps of:

(a) with said compensator movable surface being in a partial pinching position, moving the outlet movable surface from a flow permitting position to a complete tube pinching position while moving the inlet movable surface from a complete tube pinching position to a flow permitting position to permit flow of material from the said source and to prevent egress of work material in said tube means out said outlet end and to fill the flexible tube,
(b) preventing said flow from said source by moving said inlet movable surface to a complete tube pinching position and moving the outlet movable surface back to a flow permitting position,
(c) moving said displacement surface from a non tube pinching position toward a pinching position to cause displacement of material through said outlet end, and then,
(d) moving said outlet movable surface from the flow permitting position back to its pinching off position,
(e) substantially simultaneous with step (d), moving said compensator movable surface in a direction opposite to the movement of outlet movable surface and a distance proportional to the relative sizes of said outlet movable surface and said compensator movable surface,
whereby the volume of flowable work material in said tube means displacingly pumped by said displacement movable surface is substantially independent of the effect of movement of said outlet movable surface toward its pinching off of flow position.

3 more elements

Compact high precision versatile apparatus for positive displacement dispensing of a work liquid from a source of flowable work material, flow control means for receipt of flowable work material from said source and for precision displacement of said flowable work material to a dispensing outlet, said flow control means comprising frame means, flexible tube means mounted on said frame means, a displacement member movable with respect to said flexible tube means and said frame means, inlet valve tube pinching means and outlet valve tube pinching means, means for causing said inlet valve tube pinching means and said outlet valve tube pinching means to be movable in timed relationship to said displacement member and to each other to alternately permit filling of said flexible tube means and displacement from said flexible tube means of said work material for delivery to said dispensing outlet, rotary motion control means for said displacement member mounted on said frame means for moving said displacement member toward and away from pinching engagement with said flexible tube, said motion control means comprising rotary electric means and translation means, said translation means being comparable to translate rotary motion of said rotary electric means into rectilinear movement of said displacement member into and out of pinching movement of said displacement member to cause thereby displacement of a volume of work material for dispensing of work material at said dispensing outlet, said flow control means further comprising compensator means associated with said outlet valve tube pinching means, said compensator means being disposed for engagement with said flexible tube means, and linking means pivotally mounted on said frame means and interconnecting said compensator means and said outlet valve pinching means for movement in opposite directions with respect to said flexible tube means.

Dependencies are inferred from the claim text.