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GB2188248A - Improvements in and relating to proportioning of constituents of a mixture - Google Patents
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GB2188248A - Improvements in and relating to proportioning of constituents of a mixture - Google Patents

Improvements in and relating to proportioning of constituents of a mixture Download PDF

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Publication number
GB2188248A
GB2188248A GB08705177A GB8705177A GB2188248A GB 2188248 A GB2188248 A GB 2188248A GB 08705177 A GB08705177 A GB 08705177A GB 8705177 A GB8705177 A GB 8705177A GB 2188248 A GB2188248 A GB 2188248A
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GB
United Kingdom
Prior art keywords
liquid
particulate material
duct
inlet means
mixture
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08705177A
Other versions
GB8705177D0 (en
GB2188248B (en
Inventor
Bernard Eaton Hart
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Harben Systems Ltd
Original Assignee
Harben Systems Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Harben Systems Ltd filed Critical Harben Systems Ltd
Publication of GB8705177D0 publication Critical patent/GB8705177D0/en
Publication of GB2188248A publication Critical patent/GB2188248A/en
Application granted granted Critical
Publication of GB2188248B publication Critical patent/GB2188248B/en
Expired legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30Injector mixers
    • B01F25/31Injector mixers in conduits or tubes through which the main component flows
    • B01F25/314Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced at the circumference of the conduit

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)

Abstract

The proportion of liquid and particulate material in a liquid/ particulate material mixture supplied to a system in which the mixture is drawn into the system by suction, e.g. a gun producing an abrasive jet as described in GB.2116637, is variable. A duct (10) has a first inlet (11) for liquid, an outlet (13) for the liquid/particulate material mixture and openings (12a) opening laterally into duct (10) downstream of inlet (11) for particulate material. In use a variable quantity of liquid is supplied to inlet (11) variation being effected by means of a control valve. It is found that with this arrangement liquid is preferentially drawn through duct (10) by the suction created by the system so that a variation in the quantity of liquid supplied to inlet (11) will produce an inverse variation in the quantity of particulate material drawn in through inlets (12a) to produce a corresponding variation in the proportions of liquid and particulate material drawn out of outlet (13). <IMAGE>

Description

SPECIFICATION Improvements in and relating to particulate material supply The present invention relates to improvements in and relating to systems utilising a mixture of pa rticu late material and liquid, in which the mixture is drawn into the system by suction, and specifically to the control of the relative proportions of particulate material and liquid supplied to such a system.
Such a system may for example be used to supply a mixture of abrasive particulate material and water to a gun outlet producing a high pressure water and particulate material jet. Such a system is for example described in GB.2116637, in which particulate material saturated with water is withdrawn from a hopper and supplied to the gun outlet, high pressure water being separately supplied to the gun outlet, the two streams being combined in the gun outlet to provide a high pressure particulate material and water jet. The particulate material is withdrawn from the hopper by creating regions of reduced pressure at intervals along the supply pipe and in the gun outlet.
Such guns are used not only for cleaning or abrading surfaces but also for cutting. However, particularly (but not exclusively) for cutting, variation in the quantity of particulate material supplied to the gun outlet causes a variation in the cutting action of the gun and it is found that there is a need to be able to control the amount of particulate material being supplied in order to be able to control the cutting action.
According to one aspect of the present invention there is provided apparatus for controlling the proportion of liquid and particulate material in a mixture of liquid and particulate material supplied to a system in which the mixture is drawn into the system by suction, the apparatus comprising a duct having a first inlet means for liquid, a second inlet means for connection to a supply of particulate material, and an outlet for the mixture of particulate material and liquid and for connection to the system, the second inlet means being arranged downstream of the first inlet means and opening laterally into the duct such that an increase in the quantity of liquid supplied to the first inlet means causes a decrease in the quantity of particulate material entering the duct th rough the second inlet means, means for supplying liquid to the first inlet means and means for varying the quantity of liquid supplied to the first inlet means to vary the proportion of particulate material in the mixture of particulate material and liquid at the outlet.
In a preferred embodiment, the first inlet means and outlet are coaxial with the duct and the second inlet means comprises an opening in the wall of the duct whose axis is substantially perpendicularto the axis of the duct.
Advantageously, to enhance the effectiveness of the liquid supply to the apparatus, the minimum flow cross section provided by the duct for liquid upstream of the second inlet means is substantially equal to or greater than the minimum flow cross section provided by the duct downstream of the second inlet means.
In use, the duct may be immersed in a slurry of particulate material and liquid in a container, the second inlet means opening to the exterior of the duct so as to communicate with the slurry in the container, particulate material (with some liquid) being supplied thereto under gravity.
The means for varying the quantity of liquid supplied to the first inlet means may comprise a valve which is manually and/or remotely controllable.
According to another aspect of the present invention there is provided a method of controlling the proportion of liquid and particulate material in a mixture of liquid and particulate material supplied to a system in which the mixture is drawn into the system by suction, the method comprising supplying liquid to a first inlet in a duct having an outlet connected to the system, supplying particulate material to second inlet means in the duct, the second inlet means opening laterally into the duct downstream of the first inlet, and varying the quantity of liquid supplied to the first inlet so as to inversely vary the quantity of particulate material entering the duct through the second inlet means to thereby vary the proportion of liquid and particulate material in the mixture supplied to the system.
The above described apparatus may be used in carrying out the above method.
Advantageously, the maximum quantity of liquid which can be supplied to the duct is arranged in relation to operation of the system so that there is excess liquid. This excess will flow backward through the second inlet means and can be used to flush the apparatus and system connected thereto to remove particulate material therefrom, for example at the end of a period of use.
Embodiments according to the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic view of an embodiment of an assembly of a system utilising a mixture of particulate material and liquid and apparatus for controlling the proportion of particulate material and liquid in the mixture according to the present invention; Figure 2 shows a modification of the assembly of Figure 1; and Figure 3 is an enlarged axial section through an embodiment of apparatus according to the present invention.
The assembly shown in Figure 1 comprises a system generally as described in GB.2116637 in which a mixture of particulate material and liquid, for example an abrasive particulate material such as sand and water, is supplied along a pipe 1 to a gun outlet 3. High pressure liquid is supplied along pipe 2 to the gun outlet 3, the particulate material and liquid mixture in pipe 1 being drawn along pipe 1 by reduced pressure/suction created in pipe 1 at intervals therealong by devices 4which interconnect pipes 1,2, as described in GB.2116637.
In this assembly, the upstream end of pipe 1 is supplied substantially by gravity with particulate material from a hopper 5 through control means 6 which includes a liquid supply pipe 7 provided with a valve 8, liquid at relatively low pressure, for example water at a pressure of the order of 100 psi, being supplied to pipe 7. The particulate material, e.g. sand, in the hopper 5 is mixed in the hopper with liquid, e.g. water, in the form of a slurry, to increase its fluidity. In operation, a mixture of particulate material and liquid is drawn into pipe 1 through the control means 6, the proportion of particulate material to liquid in the mixture being varied, as will be described hereafter, by variation of the position of valve 8 and therefore of the quantity of liquid flowing along pipe 7.
In a modification of the system shown in Figure 3, the control means 6 is located within the hopper 5.
As shown the pipe 7 enters the hopper through the lower end or a lower portion of the hopper and the pipe 1 exits from the hopper through a wall of the hopper. Alternatively, pipes 1 and/or 7 may extend into and out of the hopper through the open top.
The control means 6 of Figure 2 is shown in more detail in Figure 3 and comprises a generally tubular body 9 defining a generally axial duct 10 therethrough. Duct 10 has a first inlet 11 coaxial with the duct 10 and which is connected to the end of pipe 7 for supply of liquid thereto, a coaxial outlet 13 from which the mixture of liquid and particulate material is drawn by suction created in pipe 1 and to which pipe 1 is connected, and second inlet means 12 opening laterally into the duct 10 for particulate material.
As shown, the second inlet means 12 are provided by a plurality of openings 1 2a in the wall of the body 9 whose axes are substantially perpendicular to the axis of duct 10 and which are arranged symmetrically around the axis of duct 10. As shown, four such openings 12a are provided though more or less such openings may be provided.
In use of the above described apparatus, by virtue of the suction created in pipe 1, liquid and/or particulate material (mixed with liquid) is drawn into duct 10 through its inlets and supplied to pipe 1. The relative proportions of particulate material and liquid will depend on the state of valve 8. If valve 8 is closed so that no liquid flows along pipe 7, the mixture leaving outlet 13 will contain the maximum amount of particulate material, but will include some of the liquid from the slurry in hopper 5. As valve 8 is progressively opened, liquid from pipe 7 is preferentially drawn into pipe 1 and the amount of particulate material drawn into pipe 1 is progressively reduced producing a corresponding reduction in the proportion of particulate material in the mixture flowing out of outlet 13.If the pressure of the liquid supply to pipe 7 is sufficient relative to the suction produced in pipe 1, as valve 8 is progressively opened, there may come a point at which excess liquid is supplied to duct 10 and it is found that this excess liquid will flow out of inlet opening 1 2a to cut off the supply of particulate material to duct 10.
The valve 8 may be manually controlled atthe start of an operation to provide the required relative proportions in the mixture for that operation.
Additionally or alternatively, valve 8 may be remotely controlled by the operator of the gun so that the relative proportions of the mixture can be varied during operation of the gun. At the end of the operation, valve 8 may be fully opened or open to the point at which excess liquid is supplied to device 6 to cut off the supply of particulate material and to flush the particulate material from device 6 and the gun to avoid the risks of clogging while the system is not being used.
It has been found that the controlling effect of the liquid supplied to inlet 11, and therefore the effectiveness of the control provided by the device, can be increased by arranging duct 10 so that the minimum flow cross section provided by the duct upstream of the second inlet means 12 is substantially equal to or greater than the minimum flow cross section provided by the duct downstream of the second inlet means 12. In the apparatus shown in Figure 3, these minimum flow cross sections are substantially equal. Upstream of the second inlet means 12, the flow cross section is provided by the end of pipe 7 and is constant upstream of inlet means 12. Downstream of inlet means 12 the duct 10 is provided with a reduction to reduce the flow cross section to be substantially equal to that of the duct upstream of inlet means 12.
The reduction downstream of inlet means 12 may, as shown, be a localised reduction or may be extended throughout the part of duct 10 downstream of inlet means 12 to outlet 13. An equivalent effect could be achieved by coupling pipe 1 to outlet 13 by inserting it into the outlet rather than surrounding the outlet, as shown in Figure 3.
The apparatus shown in Figure 3 may, with slight modification, be used in the embodiment of Figure 1. For this purpose, a chamber may be provided around body 9 and surrounding the openings 12a, the chamber being connected to the outlet of hopper 5 to receive particulate material mixed with liquid therefrom.
The body 9 may be made of any suitable material, such for example as metal or plastics, and the pipes 1 and 7 may be made of any suitable conventional material.
As described above, the device 6 is orientated with the liquid inlet 11 below the outlet 12 so that liquid flows upwardly through duct 10. This represents a preferred arrangement for optimising control. However, it will be appreciated that the device can be used with the body 9 in any required orientation and the liquid flowing upwardly, downwardly or horizontally, or at an inclination to the vertical through duct 10.

Claims (23)

1. Apparatus for controlling the proportion of liquid and particulate material in a mixture of liquid and particulate material supplied to a system in which the mixture is drawn into the system by suction, the apparatus comprising a duct having a first inlet means for liquid, a second inlet means for connection to a supply of particulate material, and an outlet for the mixture of particulate material and liquid and for connection to the system, the second inlet means being arranged downstream of the first inlet means and opening laterally into the duct such that an increase in the quantity of liquid supplied to the first inlet means causes a decrease in the quantity of particulate material entering the duct through the second inlet means, means for supplying liquid to the first inlet means and means for varying the quantity of liquid supplied to the first inlet means to vary the proportion of particulate material in the mixture of particulate material and liquid at the outlet.
2. Apparatus as claimed in Claim 1, wherein the first inlet means and outlet are coaxial with the duct.
3. Apparatus as claimed in either Claim 1 or Claim 2, wherein the second inlet means comprises an opening in the wall of the duct whose axis is substantially perpendicular to the axis of the duct.
4. Apparatus as claimed in Claim 3, wherein the second inlet means comprises a plurality of said openings.
5. Apparatus as claimed in any one of the preceding claims, wherein the minimum flow cross section provided by the duct for liquid upstream of the second inlet means is substantially equal to or greater than the minimum flow cross section provided by the duct downstream of the second inlet means.
6. Apparatus as claimed in any one of the preceding claims, wherein the flow cross section of the duct is reduced downstream of the second inlet means.
7. Apparatus as claimed in claim 6, wherein the reduction in the flow cross section of the duct extends to the outlet.
8. Apparatus as claimed in claim 6, wherein the flow cross section of the duct progressively increases downstream of the reduction.
9. Apparatus as claimed in any one of the preceding claims, wherein the second inlet means opens to the exterior of the duct, the duct being intended in use to be immersed in a slurry of particulate material and liquid.
10. Apparatus as claimed in any one of claims 1 to 8, wherein in the region of the duct provided with the second inlet means, the duct is surrounded by a chamber for receiving a slurry of particulate material and liquid and into which the second inlet means open for receiving particulate material.
11. Apparatus as claimed in any one of the preceding claims, wherein the means for varying the quantity of liquid supplied to the duct comprise a valve.
12. Apparatus as claimed in Claim 11, wherein the valve is manually operable.
13. Apparatus as claimed in Claim 11, wherein the valve is remotely controllable.
14. Apparatus for controlling the proportion of liquid and particulate material in a mixture of liquid and particulate material supplied to a system substantially as herein described with reference to the accompanying drawings.
15. An assembly comprising a system utilising a mixture of liquid and particulate material and apparatus for controlling the proportion of liquid and particulate material in the mixture supplied to the system as claimed in any one of the preceding claims.
16. An assembly as claimed in Claim 15, comprising a container for a slurry of particulate material and liquid and wherein the duct is arranged in the container to be immersed in the slurry with the second inlet means communicating with the container.
17. An assembly as claimed in either claim 15 or claim 16, wherein the duct is arranged in the container with the first inlet means below the outlet.
18. A method of controlling the proportion of liquid and particulate material in a mixture of liquid and particulate material supplied to a system in which the mixture is drawn into the system by suction, the method comprising supplying liquid to a first inlet in a duct having an outlet connected to the system, supplying particulate material to second inlet means for the duct, the second inlet means opening laterally into the duct downstream of the first inlet, and varying the quantity of liquid supplied to the first inlet so as to inversely vary the quantity of particulate material entering the duct through the second inlet means to thereby vary the proportion of liquid and particulate material in the mixture supplied to the system.
19. A method as claimed in claim 18, using apparatus as claimed in any one of Claims 1 to 17.
20. A method as claimed in either Claim 18 or Claim 19, wherein particulate material is mixed with liquid in the form of a slurry and is supplied to the second inlet means by gravity.
21. A method as claimed in any one of claims 18 to 20, wherein the liquid flows upwardly through the duct between the first inlet and the outlet.
22. A method for controlling the proportion of liquid and particulate material in a mixture of liquid and particulate material supplied to a system substantially as herein described with reference to the accompanying drawings.
23. A gun for producing a jet comprising high pressure water and particulate material substantially as herein described with reference to the accompanying drawings.
GB8705177A 1986-03-07 1987-03-05 Improvements in and relating to particulate material supply Expired GB2188248B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB868605668A GB8605668D0 (en) 1986-03-07 1986-03-07 Supplying particulate material

Publications (3)

Publication Number Publication Date
GB8705177D0 GB8705177D0 (en) 1987-04-08
GB2188248A true GB2188248A (en) 1987-09-30
GB2188248B GB2188248B (en) 1989-11-15

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ID=10594223

Family Applications (2)

Application Number Title Priority Date Filing Date
GB868605668A Pending GB8605668D0 (en) 1986-03-07 1986-03-07 Supplying particulate material
GB8705177A Expired GB2188248B (en) 1986-03-07 1987-03-05 Improvements in and relating to particulate material supply

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB868605668A Pending GB8605668D0 (en) 1986-03-07 1986-03-07 Supplying particulate material

Country Status (1)

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GB (2) GB8605668D0 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1459374A (en) * 1974-11-04 1976-12-22 Continental Oil Co Method and apparatus for hydraulically transporting solids
US4100614A (en) * 1976-06-18 1978-07-11 Houdaille Industries, Inc. Method for polymer dissolution

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1459374A (en) * 1974-11-04 1976-12-22 Continental Oil Co Method and apparatus for hydraulically transporting solids
US4100614A (en) * 1976-06-18 1978-07-11 Houdaille Industries, Inc. Method for polymer dissolution

Also Published As

Publication number Publication date
GB8705177D0 (en) 1987-04-08
GB8605668D0 (en) 1986-04-16
GB2188248B (en) 1989-11-15

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Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19970305