GB2446956A

GB2446956A - Mixing apparatus with safety cut-out

Info

Publication number: GB2446956A
Application number: GB0803271A
Authority: GB
Inventors: Campbell Brown; Conor Mcalinden
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-02-23
Filing date: 2008-02-22
Publication date: 2008-08-27
Also published as: GB0803271D0; GB0703584D0

Abstract

A mixing apparatus 10 comprising a mixing chamber 16 in which a mixing device 26 is provided, a motor 22 for driving mixing device 26, and means for selectably disabling motor 22. A locking device 44 is mountable on the exterior of the apparatus and operable between a locking state, in which it holds the mixing chamber 16 closed and in which it causes said disabling means to enable motor 22, and a non-locking state in which it allows chamber 16 to be opened and in which it causes the disabling means to disable motor 22. There may be a conveying chamber 14 upstream of mixing chamber 16, the two chambers separatable at their interface 18. At interface 18 there may be an interspersing cone 32 with a flared portion 34 to aid mixing. The apparatus may be used for mixing mortar or cement with water and be used in conjunction with a silo 12.

Description

Mixing Apparatus

Field of the Invention

The present invention relates to mixing apparatus. The invention relates particularly to apparatus for mixing a dry substance, e.g. cement or mortar, with a liquid, e.g. water. The apparatus is particularly suited for use with silos, especially dry mortar silos.

Background to the Invention

A mixing apparatus can be provided at the outlet of a silo in order to mix the contents of the silo with another substance as it is being dispensed. In the case of silos that contain dry mortar, or a similar substance, the mixing apparatus may be provided to mix the mortar with water. S.. S

*.... It would be desirable to provide a mixing apparatus, suitable for use with a silo, :* with improved safety features and/or improved performance. S..

Summary of the Invention S. ** * S S * S

A first aspect of the invention provides a mixing apparatus comprising a body that provides at least one chamber, mixing means located in said at least one chamber, means for driving said mixing means, and means for selectably disabling said driving means, wherein said body includes at least one closable opening for allowing access to the interior of said body, and wherein a locking device is mountable on the exterior of the body and is co-operable with said disabling means, the locking device being operable between a locking state, in which it holds said at least one closable opening closed and in which it causes said disabling means to enable said driving means, and a non-locking state in which it allows said at least one closable opening to open and in which it causes said disabling means to disable said driving means.

Advantageously, the mixing apparatus will only operate when the locking device is in its locking state, in which case it holds the chamber(s) closed thereby preventing a user from injuring himself. Should the user wish to access the interior of the body, the locking device must be removed in which case the driving means is disabled. Disabling the drive means may be achieved by any suitable means, e.g. isolating it from its power source, or mechanically disengaging the mixing device (and/or conveying means when present) from the portion of driving means that would otherwise drive it.

The mixing apparatus typically comprises a conveying chamber, a mixing chamber, means for conveying material along the conveying chamber into the * 15 mixing chamber, means for mixing said material when in the mixing chamber, and drive means for driving the conveying means and, typically, also the mixing * * means. ** ** * S *

*:* Advantageously, the locking device comprises means, e.g. a bar, for releasably holding the mixing and/or conveying chambers in a closed state, said holding : ,* means including, or being coupled to, means for operating an isolation device, said isolation device being operable to connect or isolate said drive means from its power source (or to isolate the conveying means and/or mixing means from the drive means) wherein when the holding means adopts a holding state in which it holds the or each chamber in the closed state, the operating means cooperates with the isolation means to connect the drive means from its power supply (or to connect the conveying means and/or mixing means to the drive means), and when the holding means is removed from the holding state, the operating means cooperates with the isolation means to isolate the drive means from its power supply (or to isolate the conveying means and/or mixing means from the drive means).

Preferred features are recited in the dependant claims.

From a second aspect, the invention is characterised by an interspersing member located at the interface between the conveying and mixing chambers and including a flared portion located in said mixing chamber.

From a third aspect, the invention is characterised by a mixing device comprising one or more sets of agitating blades extending substantially radially from a shaft, the blades, or subsets thereof, preferably being radially and longitudinally spaced apart on the shaft and, preferably, obliquely disposed with respect to a normal plane.

From a fourth aspect, the invention is characterised by an arrangement whereby said conveying means is fixed with respect to the chambers to substantially prevent axial movement of the conveying means. * S S...

* From a fifth aspect, the invention is characterised by the provision of separable * conveying and mixing chambers and the provision of one or more frangible I..

fastening members to hold the chambers together during normal use. *5 ** * S S S *

From a sixth aspect, the invention is characterised by the provision of a one way valve for controlling the flow of liquid into the apparatus, the valve including a stop member, e.g. a ball, for closing the valve, and resilient biasing means, e.g. a compression spring, arranged to urge the stop member into its closed position.

The aforementioned aspects of the invention may each be provided independently of the other, or together in any combination as will be apparent to a skilled person.

Further advantageous aspects of the invention will become apparent to those skilled in the art upon review of the following description of a specific embodiment of the invention and with reference to the accompanying drawings.

Brief Description of the Drawings

An embodiment of the invention is now described by way of example and with reference to the accompanying drawings in which: Figure 1 is a line drawing of a mixing apparatus embodying the invention in which an interspersing cone is highlighted; Figure 2 shows the interspersing cone in more detail; * 15 Figure 3 is a line drawing of the mixing apparatus in which a safety isolating bar is highlighted; **** * * **** Figure 4A is a line drawing of the mixing apparatus in which an auger is highlighted; Figure 4B shows the auger of Figure 4A; Figure 5A is a line drawing of the mixing apparatus in which a mixing device is highlighted; Figure SB shows the mixing device; Figure 6 is a line drawing of the mixing apparatus in which a sheer pin arrangement is highlighted; and Figure 7 shows line drawings of a valve for use with the mixing apparatus, the drawings including end views and side section views of the valve when in two parts A and B, and a side sectional view of the valve when assembled.

Detailed Description of the Drawings

Referring now to the drawings and to Figure 1 in particular, there is shown, generally indicated as 10, a mixing apparatus embodying the invention. In the illustrated embodiment, the apparatus 10 is used in conjunction with a silo 12 (partly shown in broken outline in Figure 1), although it may alternatively be used with any other container having an outlet through which its contents can be dispensed, typically under gravity. In use, the apparatus 10 mixes dry, flowable material (not shown) from the silo 12, especially but not exclusively mortar, cement or the like, with a liquid, typically water. In the following description, it is * 15 assumed that the apparatus 10 is intended to mix mortar with water, although it will be understood that this is not limiting to the invention. The silo and the 0Ss.

mixing apparatus may together be said to provide a dispensing apparatus. S. ** * . *

*:. The apparatus 10 comprises a body 11, typically formed from metal, adapted to provide a conveying chamber 14 and a mixing chamber 16. The chambers 14, 16 : . are disposed end-to-end and abut with one another at interface 18 which is at least partially open, or capable of being opened to allow material to be passed from the conveying chamber 14 into the mixing chamber 16. The chambers 14, 16 are preferably coaxial and may be substantially circular in transverse cross-section.

Preferably, the chambers 14, 16 are separable at the interface 18, e.g. by means of one or more hinges (not shown) or other joints provided at the interface 18.

Typically, the chambers 14, 16 are formed separately from one another and are pivotably coupled to one another by any suitable means. In the illustrated * 30 embodiment, the mixing chamber 16 capable of pivoting with respect to the conveying chamber 14 about an axis that is substantially perpendicular to the longitudinal axis of the chambers, e.g. an in use vertical axis. Alternatively, they may be integrally formed with one another.

The conveying chamber 14 contains means for conveying material along the chamber 14 (left-to-right as viewed in Figure 1) and into the mixing chamber 16.

The conveying means conveniently takes the form of an auger 20 (not shown in Figure 1) which is located in the chamber 14 and rotatable with respect thereto about an axis which is substantially coincident with or parallel with the longitudinal axis of the chamber 14.

The apparatus 10 further includes means for driving the auger in the form of, typically, a motor 22 and, usually, a gearbox 24.

The mixing chamber 14 contains a mixing device, or agitator 26, for mixing mortar with water. The agitator 26 is located in the chamber 16 and is rotatable with respect thereto about an axis that is substantially coincident with or parallel S...

with the longitudinal axis of the chamber 16. Conveniently, the agitator 26 is . :. coupled to the auger 20 for rotation therewith. S..

The apparatus 10 has an inlet 28 provided in the conveying chamber 14 through which mortar may be introduced into the chamber 14 from the silo 12. An outlet is provided in the mixing chamber 16, typically at or adjacent the end of the chamber 16 that is distal the chamber 14. Preferably, the outlet 16 is arranged to dispense the contents of the chamber 16 in a substantially downwards direction during use.

A liquid inlet (not shown) is provided for introducing water into the body 11, typically into the mixing chamber 16, the liquid inlet preferably being located at or adjacent the interface 18.

The free end 17 of the mixing chamber 16 may include a hatch 19 which, when open, allows access to the interior of the chamber 16.

In use, mortar enters the conveying chamber 14 from the silo 12 and is conveyed into the mixing chamber 16 by the auger 20. Upon entry to the chamber 16, the mortar comes into contact with water that has been introduced into the chamber 16 via the liquid inlet. The agitator 26 mixes the water and mortar and conveys the mixture along the chamber 16 to the outlet 30 whereupon it is dispensed.

Referring in particular to Figures 1 and 2, an interspersing funnel or cone 32 is provided at interface 18. The cone 32 has a sleeve-like body with flared portion 34 located in the mixing chamber 16, the flared portion 34 being flared in a direction away from the interface 18. The arrangement is such that mortar entering chamber 16 from chamber 14 does so through the cone 32. The liquid inlet is arranged to direct the incoming water onto the inner surface of the flared portion 34 of the cone 32 thereby causing the water to be dispersed. It is preferred S...

*. that the water is directed onto the cone 32 at an angle of approximately 30 to horizontal or vertical during use. The action of the cone 32 on the water improves * the mixing of the water with the mortar.

Advantageously, a dispersing head 36 comprising one or more dispersing blades 38 is located in the cone 32 and rotates in use about an axis that is substantially coincident with or parallel with the longitudinal axis of the chambers 14, 16.

Conveniently, this is achieved by coupling the head 16 to the auger 20. The blades 38 are spaced radially around the head 36 and are preferably disposed at an angle of approximately 25 to the radius of the head 36. The action of the head 36 on the mortar and water further improves the mixing.

Preferably, one or more apertures or slots (not shown) is formed in the in use lower part of the flared portion 34 of the cone 32 to allow a quantity of mortar to fall beneath the cone 32. In this way, any water which gathers beneath the cone 32 during use can be absorbed.

Referring now in particular to Figure 3, there is shown a safety mechanism 40 comprising a locking device, or member, in the preferred form of a bar 42. The bar 42 is mountable to the exterior of the chambers 14, 16 by means of one or more supports 44. The bar 42 is mountable on and removable from the supports 44 by, in this example, sliding movement of the bar 42 in an axial direction. The locking device preferably comprises at least one elongate substantially rigid member but may take alternative forms. For example, the locking device may alternatively comprise one or more wires, webs or other flexible, but preferably non-elastic, members.

The bar 42 extends at least partially along the length of the chambers 14, 16, and in particular extends across the, or each, location where the chambers 14, 16 can be opened to allow access to their interior. In the illustrated embodiment, the bar a...

* ... 42 extends along substantially the entire length of the chambers 14, 16 across the hatch 19 and the interface 18 since it is these locations where the chambers 14, 16 * can be opened. *. *

The bar 42 includes a projection 46, or other part, typically located at one end and conveniently projecting substantially axially from the bar 42, which is insertable into and removable from an isolating switch 50 in order to make or break the switch 50. The isolating switch 50 is incorporated into the electrical power supply system (not shown) for the motor 22 such that, when the projection 46 is inserted into the switch 50, electrical power can be supplied to the motor 22, and when the projection 46 is removed from the switch 50, the motor 22 is isolated from its power supply.

The bar 42 may adopt an installed, or locking, state (as shown in the drawings) in which the projection 46 is inserted into the switch 50 and in which the bar 42 is held in place by the supports 44. In this state, power may be supplied to the motor 22 and access to the interior of the chambers 14, 16 is prevented since the bar 42 prevents the hatch 19 from being opened and prevents the chambers 14, 16 from being separated at the interface 18.

In order to access the interior of the chambers 14, 16, the bar 42 must be removed from its supports 44. In the preferred embodiment this is done by sliding the bar 42 axially (from left to right as viewed in Figure 3) out of the supports 44. In so doing, the projection 46 is removed from the switch 50 and the motor 22 is isolated. Hence, the interior of the chambers 14, 16 cannot be accessed while the motor 22 is powered. In the illustrated embodiment, the switch 50 is an electrical switch for isolating the motor 22 (which is electrically powered) from the electrical power source. More generally, the switch may comprise any type of isolation means for isolating the motor from its source of power (which need not necessarily be electrical -for example, the power source could be hydraulic or : pneumatic). Isolation in this context is intended to cover disconnection from the power source such that the motor is switched off. Moreover, it is not essential that * a part of the bar 42, or other locking device, provides a mechanical interaction * with the switch 50 or other isolation means. Instead, the locking device could be **.

electrically, or opto-electrically, coupled to switch/isolation means. Hence, any part of the locking device could be arranged for interaction with the isolation means to selectively isolate the motor from its power depending on the state of the locking device.

Preferably, the bar 42 can be secured in the locked state. This may be achieved by arranging for the bar 42 to be axially rotatable in the supports 44 and providing one or more pins 52 on the bar 42 and corresponding slot(s) 54 in the supports 44 (or vice versa). Hence, the bar 42 is rotatable in the supports 44 into and out of a locked state in which the pins 52 are located in the slots 54 thereby preventing the bar 42 from being removed from the supports 44. The bar 42 may be secured in the locked state by means of any suitable device, e.g. a padlock (not shown).

Referring now to Figure 4 in particular, it will be seen that the auger 20 includes, or is coupled to, a shaft 21 which is coupled to the gearbox 24 in order that the auger 20 may be driven by the motor 22. A bearing 23 is provided at a point of entry to the chamber 14. The free end 25 of the shaft 21 is fixed to the housing of the gearbox 24, or other associated housing, such that the shaft 21 may rotate axially but not move in an axial direction. This may be achieved by means of a draw bolt fixture 41, or similar fixing, provided axially of the shaft 21. This arrangement substantially prevents the auger 20 from moving axially during use and this reduces the forces, and therefore the wear, exerted on the other components of the apparatus 10 that are acted upon directly or indirectly by the auger 20.

Referring now in particular to Figure 5, the agitator 26 includes a shaft 27 which in use is coupled to the auger 20 and is substantially coaxial therewith. The shaft 27 is axially rotatable and in use is rotated by the auger 20. One or more scraping blades 29 are provided on the shaft at or adjacent the end of the shaft which in use is coupled to the auger 20. The scraping blades 29 reduce the amount of material that may otherwise gather in the chamber 16 adjacent the interface 18, and particularly around the cone 32. The shaft 27 also carries a set of agitation blades 31 which serve to mix the mortar and water during use. Advantageously, the blades 31 extend substantially radially from the shaft 27 are obliquely disposed with respect to a plane that is perpendicular to the longitudinal axis of the shaft 27 so that they move the mixture along the chamber 16 (from left to right as viewed in Figure 5) towards the outlet 30 as the shaft 27 rotates. More advantageously, the blades 31 are arranged into two sets 31 A, 31 B, which are, preferably, substantially perpendicular with one another and mutually interspersed as shown.

Optionally, one or more bracing elements 33 may be fixed across the blades 31, typically a respective one brace 33 for each set 31A, 3 lB. The braces 33 may be substantially parallel with the shaft 27 or, preferably obliquely disposed with respect thereto. The braces 33 lend support to the blades 31 as well as assisting in the mixing process.

Preferably, the shaft 27 carries a set of one or more paddles 35 located, in use, adjacent the outlet 30. The paddles 35 extend substantially radially from the shaft 27 and may be disposed substantially in a plane in which the shaft 27 lies. In use, the paddles 35 direct the mixed mortar and water to the outlet 30.

Preferably, an end plate 37 is provided on the shaft 27 disposed in a plane that is substantially perpendicular with the longitudinal axis of the shaft 27. The end plate 37 acts as a stop to inhibit the mixture from reaching the hatch 19 at the end of the chamber 16.

Referring now in particular to Figure 6 of the drawings, one or more removable sheer pins 60 are provided at the interface 18 for holding the chambers 14, 16 together. By way of example, each of the chambers 14, 16 may include a * ** respective flange plate, the plates being arranged to overlap or abut when the :..: chambers 14, 16 are closed together as shown in the drawings. Each plate includes an aperture for receiving a respective sheer pin 60, the apertures being in register when the chambers 14, 16 are together to allow the sheer pins 60 to be inserted through both sets of apertures. The sheer pins 60 are sufficiently robust to hold the chambers together during normal use, but are frangible such that they break under forces that are out of the ordinary. Hence, should, for example, the free end of the chamber 16 be knocked accidentally by a vehicle or machine when on site, the sheer pins 60 break thereby allowing the chambers 14, 16 to separate. This limits the damage caused to the apparatus 10 since it prevents, in particular, the chambers 14, 16 from being bent out of shape. It is noted that in preferred embodiments, the chambers 14, 16 are pivoted or hinged together along an, in use, substantially vertical or horizontal axis. Hence, when the sheer pins 60 break, the chambers 14, 16 will pivot with respect to one another.

Referring now to Figure 7 of the drawings, there is shown a one-way valve 70 for controlling the flow of water into the apparatus 10. The valve 70 need not necessarily be part of the apparatus 10 itself, but it is associated therewith by incorporation into the means for supplying water to the apparatus. The valve 70 includes an inlet 72 and an outlet 74 and a bore 76 running therebetween. The bore 76 includes a seat 78 for a ball 80, or other closure member. The bore is dimensioned to receive and retain resilient biasing means in the preferred form of a compression spring 82. The spring 82 is biased to urge the ball 80 into the seat 78 thereby closing the bore 76 and shutting the valve 70. The valve 70 may be formed in two parts as shown in the drawings.

In use, when the water pressure at the inlet is at a pressure sufficient to dislodge the ball 80 from the seat 78, water is able to flow through the valve 70 to the apparatus 10. When the water pressure drops sufficiently, the force of the spring 82 overcomes the water pressure to return the balI 80 to the set 76 and shut off the *:*::* water supply. The valve 70 is particularly advantageous in this application since *.*.

it exhibits a fast shut off time (in comparison with, say, a solenoid valve) without requiring back pressure to close. This is important in the present application since controlling the quantity of the water entering the chamber 16 is instrumental in producing a mixture of the desired quality. * * * * .

The apparatus 10 and the silo 12 are typically provided on a common frame (not shown) and so used as a unit. Advantageously, a tank for storing water may also be mounted on the frame, optionally together with means, e.g. a pump and pipes, for feeding water from the tank into the apparatus 10. Alternatively, the apparatus may be connectable to a separate water supply. Control modules (e.g. a PLC based module) for controlling the operation of the apparatus 10 may also be mounted on the frame.

The invention is not limited to the embodiment described herein which may be modified or varied without departing from the scope of the invention.

Claims

CLAIMS: I. A mixing apparatus comprising a body that provides at least

one chamber, mixing means located in said at least one chamber, means for driving said mixing means, and means for selectably disabling said driving means, wherein said body includes at least one closable opening for allowing access to the interior of said body, and wherein a locking device is mountable on the exterior of the body and is co- operable with said disabling means, the locking device being operable between a locking state, in which it holds said at least one closable opening closed and in which it causes said disabling means to enable said driving means, and a non-locking state in which it allows said at least one closable opening to open and in which it causes said disabling means to disable said driving means.
2. A mixing apparatus as claimed in claim 1, wherein said body provides a mixing chamber and a conveying chamber, the apparatus further including means for conveying material along the conveying chamber into the mixing chamber, 0*s said mixing means being provided in said mixing chamber, and wherein said mixing chamber and said conveying chamber are separable from one another at an interface, said interface providing one of said at least one closable openings.

:
3. A mixing apparatus as claimed in claim 2, wherein said mixing chamber and said conveying chamber are pivotably coupled to one another at said interface, said locking device extending across said interface in the locking state to substantially prevent said chambers from pivoting with respect to one another.
4. A mixing apparatus as claimed in any preceding claim, further including a power source for said driving means, wherein said disabling means comprises means for selectably isolating said driving means from said power source.
5. A mixing apparatus as claimed in any one of claims 1 to 3, wherein said disabling means comprises means for selectably disengaging said mixing means andior said conveying means from said driving means.
6. A mixing apparatus as claimed in any preceding claim, wherein said disabling means comprises a switch device adapted to receive a portion of said locking device when in the locking state.
7. A mixing apparatus as claimed in any one of claims 2 to 6, wherein said at least one closable opening includes a hatch, preferably located at a free end of the body, the apparatus further including means for coupling the hatch to the locking means when in the locking state to hold the hatch closed.
8. A mixing apparatus as claimed in claim 7, when dependent on claim 6, wherein said switch device is located on the other side of the interface than the hatch, preferably at the opposite end of the body, the locking device extending *4* Ia.,.' across the interface between the hatch and the switch device. * . S

*
9. A mixing apparatus as claimed in any preceding claim, wherein, in the locking **.

state, said elongate member extends along at least part of, and substantially parallel with, the body.
10. A mixing apparatus as claimed in any preceding claim, wherein said locking device comprises a substantially rigid elongate member.
11. A mixing apparatus as claimed in any preceding claim, wherein at least one support member is provided on the exterior of the body for receiving said locking device.
12. A mixing apparatus as claimed in claim 11 wherein said at least one support member is arranged to allow sliding movement of the locking device in a direction substantially parallel with the longitudinal axis of the body.
13. A mixing apparatus as claimed in claim 11 or 12, wherein said at least one support member is arranged to allow pivoting movement of the locking device about its longitudinal axis.
14. A mixing apparatus as claimed in claim 13, wherein at least one projection is provided on said locking device, and at least one respective recess is provided in said at least one support member for receiving said at least one respective projection depending on the relative orientation of the locking device with respect to said at least one support member thereby to prevent removal of the locking device from the at least one support member. * *$
15. A mixing apparatus as claimed in any preceding claim, wherein said body * * provides a mixing chamber and a conveying chamber, the apparatus further :**. including means for conveying material along the conveying chamber into the mixing chamber, said mixing means being provided in said mixing chamber, and wherein an interspersing member located substantially at the interface between the ** ** : * . conveying and mixing chambers, the interspersing member being shaped to define a passage through which material may, in use, pass from the conveying chamber into the mixing chamber, and including a flared portion located in said mixing chamber.
16. A mixing apparatus as claimed in claim 15, further including means for introducing liquid into the body such that the liquid is directed onto the inner surface of the flared portion of said interspersing member.
17. A mixing apparatus as claimed in any preceding claim, wherein said body provides a mixing chamber and a conveying chamber, the apparatus further including means for conveying material along the conveying chamber into the mixing chamber, said mixing means being provided in said mixing chamber, and wherein said conveying means includes at least one radially projecting paddle located substantially at said interface.
18. A mixing apparatus as claimed in any preceding claim, wherein the mixing device comprises one or more sets of agitating blades extending substantially radially from a shaft, the blades, or subsets thereof, preferably being radially and longitudinally spaced apart on the shaft and, preferably, obliquely disposed with respect to a normal plane.
19. A mixing apparatus as claimed in any preceding claim, wherein said body provides a mixing chamber and a conveying chamber, the apparatus further including means for conveying material along the conveying chamber into the mixing chamber, said mixing means being provided in said mixing chamber, and * * wherein said conveying means is fixed with respect to the chambers to * e .

** * substantially prevent axial movement of the conveying means. ** ** * .

*:.
20. A mixing apparatus as claimed in any one of claims 2 to 19, wherein one or more frangible fastening members are provided to hold the mixing and conveying chambers together during normal use.
21. A mixing apparatus as claimed in any preceding claim, wherein a one-way valve is provided for controlling the flow of liquid into the apparatus, the valve including a stop member for closing the valve, and resilient biasing means arranged to urge the stop member into its closed position.
22. A mixing apparatus as claimed in any preceding claim, further including an inlet for receiving material to be mixed, said inlet being adapted for connection to the outlet of a silo.
23. A dispensing apparatus comprising a silo and a mixing apparatus as claimed in any preceding claim.
24. A mixing apparatus substantially as hereinbefore described with reference to the accompanying drawings.
25. A dispensing apparatus substantially as hereinbefore described with reference to the accompanying drawings. * ** * * . * ** S... * S *..S S. *S * S S * *

S **.

S SS 55 * * S * S