US3908862A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ratio controlled mixing of liquids
Assignee: Milacron Inc
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Filing: 1974-08-29
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Granted: 1975-09-30
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Expires: 1994-08-29
Abstract
Abstract Apparatus and method are described for the controlled mixing of liquids in a predetermined ratio and is especially suitable for the dispensing of predetermined ratios of polyol and polyisocyanate liquids in the liquid injection molding of polyurethane articles. The ratio control is achieved by a masterslave relationship between at least two metering pumps of the plunger or piston type which are position coupled and inject on a common programmed velocity profile (in the master system), but with each system controlled by an automatic velocity feedback control loop (a closed loop system) wherein the reference signal into the slave automatic control system (typically the polyol system) is obtained in a suitable ratio from the master automatic control system (typically the poly isocyanate system). The method includes continuing to drive the metering pumps past the time that mixing is cut off.
Inventors
- 👤 Rangasami Sarat Chandra
- 👤 Kirby Lee Stone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:46
CPC Classifications
G; G05; G05D; G05D11/00; G05D11/02; G05D11/13; G05D11/131; G05D11/132; B; B29; B29B; B29B7/00; B29B7/30; B29B7/58; B29B7/72; B29B7/74; B29B7/7404; B29B7/7471; B29B7/7476; B29B7/748; B29B7/76; B29B7/7615; B29B7/7626; B29B7/7663; B29B7/7684; B29B7/7689; B29B7/7694; B29B7/80; B29B7/82; B29B7/826
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
312 words
Apparatus for feeding liquids in a preselected ratio from at least two separate sources and which have automatic control systems arranged in a master and slave relationship to effectuate said ratio comprising: a. first and second positive displacement liquid feed means; b. first and second means for measuring the rate at which, respectively, each of said first and second liquid feeding means dispenses its respective liquid; c. first and second means for measuring the distance through which the respective liquid displacement elements in each of said first and second feeding means moves while feeding its respective liquid; d. first and second feedback control system means, for automatically controlling said first and second feeding means, respectively, by feeding back signals from, respectively, said first and second rate measuring meanS to a summing junction in the respective control systems; e. ratio control means for receiving a plurality of different input signals and in response thereto producing a plurality of output signals each having a preselected ratio to its corresponding said input signal; f. reference signal means for providing to the summing junction of said first feedback system and to said ratio means input a signal representing a reference rate for said first feeding means to dispense its liquid; g. a third summing junction for receiving signals from an output of said ratio means representative of the product of said ratio means times the output signal from said first distance measuring means and the feedback signal from said second distance measuring means and to feed forward the summed signal thereby produced to the summing junction of said second feedback control system; and h. means connecting one of said ratio means outputs to said second feedback system summing junction to provide thereto a signal representing the product of said ratio times said reference signal whereby said second feeding means is slaved to said first feeding means.
Claim 2
Dependent Claim
312 words
Apparatus for feeding liquids in a preselected ratio from at least two separate sources and which have automatic control systems arranged in a master and slave relationship to effectuate said ratio comprising: a. first and second positive displacement liquid feed means; b. first and second means for measuring the rate at which, respectively, each of said first and second liquid feeding means dispenses its respective liquid; c. first and second means for measuring the distance through which the respective liquid displacement elements in each of said first and second feeding means moves while feeding its respective liquid; d. first and second feedback control system means, for automatically controlling said first and second feeding means, respectively, by feeding back signals from, respectively, said first and second rate measuring meanS to a summing junction in the respective control systems; e. ratio control means for receiving a plurality of different input signals and in response thereto producing a plurality of output signals each having a preselected ratio to its corresponding said input signal; f. reference signal means for providing to the summing junction of said first feedback system and to said ratio means input a signal representing a reference rate for said first feeding means to dispense its liquid; g. a third summing junction for receiving signals from an output of said ratio means representative of the product of said ratio means times the output signal from said first distance measuring means and the feedback signal from said second distance measuring means and to feed forward the summed signal thereby produced to the summing junction of said second feedback control system; and h. means connecting one of said ratio means outputs to said second feedback system summing junction to provide thereto a signal representing the product of said ratio times said reference signal whereby said second feeding means is slaved to said first feeding means.
Claim 3
Dependent Claim
56 words
Apparatus according to claim 1 wherein: a. said first and second position displacement means each comprises a plunger reciprocable within a cylinder and a servovalve to control reciprocation of said plunger; and b. said first and second distance measuring means each measures the increments of a stroke of said plunger to discharge liquid from said cylinder.
Claim 4
Dependent Claim
34 words
Apparatus according to claim 2, wherein each of said distance measuring means includes a electrical potentiometer the output signal from which is representative of the position to which the plunger associated therewith has moved.
Claim 5
Dependent Claim
50 words
Apparatus according to claim 2, wherein each of said servo motor includes a hydraulic motor and a transducer to receive actuating electrical signals from its respective said feedback means in response to which it produces hydraulic signals to drive said motor by an amount representative of the respective actuating signal.
Claim 6
Dependent Claim
56 words
Apparatus according to claim 2, wherein said reference signal means further comprises an adjustable rate profile system that further includes means to preselect and provide a reference signal representing the rate of the first feeding means at predetermined increments of distance and means to receive signal representing said increments from the first said distance is provided.
Claim 7
Dependent Claim
37 words
Apparatus according to claim 1, wherein: a. said first and second rate measuring means are each an electrical tachometer providing a signal representative of the velocity with which said liquids are respectively fed by said feeding means.
Claim 8
Dependent Claim
69 words
Apparatus according to claim 1, wherein each of said reference signal means comprises an adjustable rate or velocity profile system that further includes means to preselect and provide a reference signal representing the rate of the first feeding means at predetermined increments of distance and means to receive signals representing said increments from the first said distance measuring means whereby an adjustable rate profile correlated with distance is provided.
Claim 9
Dependent Claim
46 words
Apparatus for feeding according to claim 1 further including i. a mixing head connected to and for receiving liquids from both said first and second feeding means and having (1.) an expandable chamber into which streams of said liquids are directed into contact with each other,
Claim 10
Dependent Claim
60 words
Apparatus according to claim 8, wherein both said feeding means and said mixing head each comprises a plunger mounted to reciprocate within a chamber, and the mixing head chamber has longitudinally extending slots that are uncovered by said plunger to admit liquids for mixing and covered to prevent same, said mixing head plunger constituting said means to admit and prevent.
Claim 11
Dependent Claim
61 words
Apparatus according to claim 8, further including: a sequencing means for sequencing mixing events so that said means to admit and prevent is positioned to admit during mixing and is then moved to prevent and to force the mixed liquids out of said chamber and said first and second liquid feeding are concurrently operated to supply liquids to said mixing head.
Claim 12
Dependent Claim
34 words
Apparatus according to claim 10, wherein: said sequencing means closes all said valves in said conduits to prevent any recirculatory flow which said means to admit and prevent is positioned to admit said liquids.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |