Preparing mixed liquids

• US 5,203,504 A
• Filed: 12/05/1991
• Issued: 04/20/1993
• Est. Priority Date: 03/17/1988
• Status: Expired due to Fees

• Current Assignee: British Technology Group Ltd.
• Original Assignee: British Technology Group Ltd.
• Inventors: Marchant, John A., Frost, Andrew R.
• Primary Examiner(s): Kashnikow, Andres
• Assistant Examiner(s): YOUNG, KAREN MERRITT
• Application Number:
  US07/801,594
• Time in Patent Office: 502 Days
• Field of Search: 239/10, 239/61, 239/62, 239/303-308, 239/310, 239/313, 239/321-323, 239/412
• US Class Current: 239/10
• CPC Class Codes: A01C 23/042 Adding fertiliser to watering systems
• CPC Class Codes: A01M 7/0092 Adding active material used as well for the introduction of fertilisers in water A01C23/042
• CPC Class Codes: B01F 2101/04 Mixing biocidal, pesticidal or herbicidal ingredients used in agriculture or horticulture, e.g. for spraying
• CPC Class Codes: B01F 23/483 using water for diluting a liquid ingredient, obtaining a predetermined concentration or making an aqueous solution of a concentrate
• CPC Class Codes: B01F 23/49 Mixing systems, i.e. flow charts or diagrams
• CPC Class Codes: B01F 25/315 wherein a difference of pressure at different points of the conduit causes introduction of the additional component into the main component B01F25/316 takes precedence
• CPC Class Codes: B01F 33/502 Vehicle-mounted mixing devices
• CPC Class Codes: B01F 35/7174 using pistons, plungers or syringes
• CPC Class Codes: B01F 35/7176 using pumps
• CPC Class Codes: B05B 12/1418 for supplying several liquids or other fluent materials in selected proportions to a single spray outlet controlling ratio of two or more flows of fluid G05D11/02
• CPC Class Codes: B05B 7/32 the fed liquid or other fluent material being under pressure
• CPC Class Codes: B05B 9/06 the delivery being related to the movement of a vehicle, e.g. the pump being driven by a vehicle wheel

Abstract

A method of preparing a mixture of a carrier liquid and an active liquid in required proportion including: providing a flow of carrier liquid, controlling a liquid flow to an appropriate portion of the carrier liquid flow from pressure drop measurements of the proportional liquid flow, displacing active liquid with the proportional liquid flow without liquid contact, and including the displaced active liquid in the carrier liquid flow, thereby producing a liquid mixture in the required proportion without a flow meter. The mixed liquid may be used in at least one of a sprayer and a nutrient film equipment. The displacement medium may be provided from the carrier liquid supply.

Claims

1. A method of preparing a mixture of a carrier liquid and an active liquid in required proportion including:

providing a flow of carrier liquid,

providing a forced liquid flow of a proportion of said carrier liquid flow,

providing a control member in a flow path of said proportional liquid flow,

making pressure difference measurements of the forced proportional liquid flow at an inlet and outlet of said control member, an inlet pressure of said control member being independent of an outlet pressure thereof,

controlling said proportional liquid flow to a selected required proportional of said carrier liquid flow from said pressure difference measurements,

displacing active liquid with said proportional liquid flow without liquid contact,

conveying said displaced active liquid freely to said carrier liquid flow,

including said displaced active liquid in said carrier liquid flow,

thereby producing a liquid mixture in said required proportion without a flow meter for said carrier or said active liquid.

2. A method of preparing mixed liquids including:

providing a supply of carrier liquid for utilization,

providing a supply of an active ingredient liquid for introduction into the carrier liquid in supply to utilization means,

pumping a supply of a displacement liquid to displace the active liquid without liquid contact and introducing the active liquid directly into the carrier liquid,

determining carrier liquid pressure to determine a carrier liquid flow rate,

measuring the amount of pumped displacement liquid and controlling said pumping with regard to said measurement and said carrier liquid flow rate to produce a mixture of active liquid with said carrier liquid of specified proportion.

3. A method according to claim 2 including controlling the amount of pumped displacement liquid in an open loop, thereby permitting a mixture of a set proportion.

4. A method according to claim 2 including controlling the amount of pumped displacement liquid in a closed loop to maintain said mixture of a required proportion in response to a sensor.

5. A method according to claim 2 in which the utilization means is at least one of a sprayer and a mechanism for dispensing nutrient solutions.

6. A method according to claim 2 including providing the displacement liquid from the carrier liquid supply.

7. A method according to claim 2 in which the utilization means is a sprayer and including controlling the volume of displacement liquid applied in accordance with control signals representing the demand for mixed liquid.

8. A method according to claim 7 in which the control signals include at least one of required concentration of active ingredient liquid, required mixed liquid flow, sprayer size and speed over the crop.

9. An apparatus to prepare a mixed liquid including:

means to supply pressurized carrier liquid along a path to utilization means,

means to contain a supply of active ingredient liquid,

an unrestricted flow path to introduce active ingredient liquid from the container means into the pressurized carrier liquid supply path,

liquid isolating means operable to displace active ingredient liquid from said container means for introduction into the carrier liquid supply path,

means to supply a displacement medium to operate the liquid isolating means to displace active ingredient liquid into the carrier liquid, and

means to control said means to supply displacement medium to produce a mixed liquid of specific properties for supply along said path to the utilization means,

the displacement medium supply means including a pump, the means to control the displacement medium supply including associated pressure transducers to detect the pressure difference across the pump and a pump control means responsive to the transducers and to pressure difference in said displacement medium supply means indicated thereby, an output pressure of said pump being independent from an input pressure of said pump.

10. An apparatus according to claim 9 in which the displacement medium is carrier liquid from the pressurized supply upstream of the unrestricted flow path.

11. An apparatus according to claim 9 in which the pump for the displacement medium is further controlled in response to signals representing the operation of the utilization means, said means being at least one of a sprayer and a mechanism for dispensing nutrient solutions.

12. An apparatus according to claim 11 in which said operation representing signals and outputs from said transducers are processed in a calculating device of a dedicated microcomputer in the pump control means to produce a pump control signal.

13. An apparatus according to claim 12 in which the utilization means is a sprayer which includes a boom and wherein said operation representing signals include sprayer speed over the ground, sprayer boom size, required active ingredient concentration, and spray liquid flow rate.

14. An apparatus according to claim 9 in which the apparatus is arranged so that the active ingredient liquid is contained until introduction into the carrier liquid.

15. An apparatus according to claim 9 in which said carrier liquid supply means includes a carrier liquid pump, said carrier liquid pump and displacement medium supply means pump being isolated from the active ingredient.

16. An apparatus according to claim 9 in which the active ingredient liquid is isolated from the displacement medium.

17. An apparatus according to claim 9 further including means to draw the active ingredient liquid into the container means by reversing the action of the displacement medium.

18. An apparatus according to claim 9 further including flushing means operable on the completion of displacement of active ingredient liquid to supply a flushing liquid to the container means and to the unrestricted flow path.

19. An apparatus according to claim 18 in which the flushing means includes a valve operable to bypass the liquid isolating means and to allow carrier liquid to flush the container means and the unrestricted flow path.

20. An apparatus according to claim 9 in which the liquid isolating means is one of a piston and a diaphragm.