System for mixing liquids

• US 5,558,435 A
• Filed: 11/08/1994
• Issued: 09/24/1996
• Est. Priority Date: 06/21/1994
• Status: Expired due to Fees

• Current Assignee: Pacific INKS Pty Limited
• Original Assignee: Pacific INKS Pty Limited
• Inventors: Marjo, Erik
• Primary Examiner(s): Scherbel, David
• Assistant Examiner(s): Till, Terrence R.
• Application Number:
  US08/336,002
• Time in Patent Office: 686 Days
• Field of Search: 222/46, 222/64, 222/77, 366/138, 366/141, 366/152.1, 366/60.1-.3, 366/179.1, 366/181.6, 366/182.2
• US Class Current: 366/141
• CPC Class Codes: B01F 23/40 Mixing liquids with liquids; Emulsifying
• CPC Class Codes: B01F 35/2218 Weight of at least one component to be mixed
• CPC Class Codes: B01F 35/832 Flow control by weighing
• CPC Class Codes: B01F 35/833 Flow control by valves, e.g. opening intermittently
• CPC Class Codes: B01F 35/8811 the weighing being effected by material receiving containers rotating or tilting under the influence of the weight of the material in those containers
• CPC Class Codes: G05D 11/134 by sensing the weight of the individual components

Abstract

A liquid mixing system for preparing batches of liquids including paints and dyes in a mixing vessel provided with agitation means; delivery of mixing constituents to the mixing vessel being computer controlled and effected by positive displacement pumps transferring liquids from individual supply conduits and reservoirs via spring loaded single action check valves; the amount of constituent added to the mixing vessel being metered by the computer on the basis of constituent liquid weight monitored by a load cell at the mixing vessel; the delivery of constituent liquid to the mixing vessel under the control of the computer becoming incremental after delivery of a percentage between 80-99.9% of the target weight to the mixing vessel in order that the precise target weight be achieved.

Claims

1. A liquid mixing system comprising a mixing vessel provided with agitation means, a load cell capable of determining the weight of material in the mixing vessel, a plurality of liquid supply conduits each conduit dedicated to transfer one of a plurality of constituent liquids from corresponding separate supply vessels to the mixing vessel, each liquid having a corresponding liquid weight;

a positive displacement pump dedicated to each supply conduit;

a computer system for controlling the pumps for controlling the supply of the plurality of constituent liquids to the mixing vessel, the amount of each constituent liquid added to the mixing vessel being metered by the computer on the basis of the corresponding constituent liquid weight monitored by the load cell at the mixing vessel, the computer being programmed to activate said positive displacement pumps for a predetermined length of time according to a predetermined weight of each constituent liquid required in the mixing vessel, the accuracy of the metering of each constituent liquid into the mixing vessel being enhanced by said computer being programmed to introduce substantially all of a predetermined quantity of each of said constituent liquids into the mixing vessel one at a time according to a predetermined sequence and, before a next constituent liquid is introduced, measuring the weight of the already-introduced constituent liquid to determine if an additional amount of said already-introduced liquid is required and, if so, reactivating said pump corresponding to said already-introduced liquid for an additional predetermined period of time until said predetermined weight is achieved.

2. The liquid mixing system of claim 1 wherein the system is provided with a means in communication with the mixing vessel for supplying a washing solvent under pressure to the mixing vessel for cleaning the mixing vessel.

3. The liquid mixing system of claim 1 wherein the computer is programmed to produce variable batch sizes of mixed liquid comprised of said plurality of constituent liquids in the mixing vessel.

4. The liquid mixing system of claim 1 wherein the computer is programmed for re-activating select ones of said positive displacement pumps in said plurality for adding constituent liquids to a first incorrectly constituted batch of liquid product in the mixing vessel so as to produce from the first incorrectly constituted batch a second correctly constituted batch of liquid product, the constituent liquids of the first batch being at least part of the constituent liquids of the second batch.

5. A liquid mixing system comprising:

a mixing vessel;

agitation means disposed in said mixing vessel;

a load cell for determining the weight of material contained in the mixing vessel;

a plurality of liquid supply conduits, each conduit in said plurality being dedicated to the transfer of one of a plurality of constituent liquids from corresponding supply reservoirs to the mixing vessel, each liquid having a corresponding liquid weight;

a plurality of supply means, each dedicated to a corresponding supply conduit, for supplying the constituent liquids to said mixing vessel;

a computer for controlling the amount of constituent liquids provided to the mixing vessel by controlling said supply means, the amount of each constituent liquid provided to the mixing vessel being metered by the computer on the basis of the corresponding constituent liquid weight monitored by the load cell at the mixing vessel;

the computer being programmed to activate a select one of said supply means according to an amount of constituent liquid required in the mixing vessel, so that the precise amount of each selected constituent liquid can be accurately measured, the computer being further programmed for re-activating select ones of said supply means for adding constituent liquids to a first incorrectly constituted batch of liquid product in the mixing vessel so as to produce from the first incorrectly constituted batch, a second correctly constituted batch of liquid product, the constituent liquids of the first batch being at least part of the constituent liquids in the second batch.

6. The liquid mixing system of claim 5, wherein the system is provided with an outlet in communication with the mixing vessel for supplying a washing solvent under pressure to the mixing vessel for cleaning the mixing vessel.

7. The liquid mixing system of claim 5, wherein the computer is programmed to produce variable batch sizes of mixed liquid comprised of said plurality of constituent fluids in the mixing vessel.

8. A method of mixing, in a mixing vessel, a composite liquid comprised of a plurality of constituent liquids with each liquid having a corresponding liquid weight, the method comprising the steps of:

(a) activating, from a plurality of conduits, a selected conduit for a predetermined length of time for supplying said mixing vessel with a selected constituent liquid in said plurality so as to provide a predetermined amount of said selected constituent liquid to said mixing vessel;

(b) measuring the weight of said selected constituent liquid in said mixing vessel;

(c) determining, based on the measured weight, the amount of said selected constituent liquid in said mixing vessel;

(d) comparing the determined amount of said selected constituent liquid to said predetermined amount;

(e) re-activating said selected conduit for a second predetermined length of time, if said determined amount is less than said predetermined amount, to supply said mixing vessel with an additional amount of said selected constituent liquid to achieve said predetermined amount in said mixing vessel;

(f) repeating steps (a)-(e) for the other constituent liquids in said plurality of constituent liquids comprising said composite liquid; and

(g) activating an agitation means when the predetermined amounts of said constituent liquids are in said mixing vessel for mixing said composite liquid in said mixing vessel.

9. The method of claims 8, wherein said re-activating step (e) further comprises scaling the composite liquid by re-activating selected conduits of said plurality of conduits for a predetermined length of time if said determined amount of a selected constituent liquid is greater than said predetermined amount, so as to maintain a predetermined ratio of constituent liquids comprising the composite liquid.

10. The method of claim 8, wherein said activating step (a) further comprises activating a selected conduit to provide between 80-99.9% of a target weight of said selected constituent liquid to said mixing vessel.