EP1819989B1

EP1819989B1 - A dispensing arrangement

Info

Publication number: EP1819989B1
Application number: EP05762852A
Authority: EP
Inventors: Laurence Richard Penn; Philip Kenneth Thompson
Original assignee: Failsafe Metering International Ltd
Current assignee: Failsafe Metering International Ltd
Priority date: 2004-07-07
Filing date: 2005-07-07
Publication date: 2011-06-15
Anticipated expiration: 2025-07-07
Also published as: WO2006003464A1; GB2415950A; ATE513189T1; GB2415950B; GB0415253D0; EP1819989A1

Abstract

A dispensing device 30 for a two component mixture, such as an adhesive, has supply conduits 36, 37 for the two mixture components. The two components are metered to a predetermined ratio by metering devices within the dispenser. The metering devices are driven by motor M under the control of a signal from a trigger located in the handle. The metering devices may be in the form of a moveable shuttle configured to dispense shots of a known volume of each component, which are then mixed in a mixer prior to dispensing. The dispensing device may be used in a factory and suspended by means 47, 48 to balance the effect of gravity.

Description

THE PRESENT INVENTION relates to a dispensing arrangement and more particularly relates to a hand-held dispensing arrangement for dispensing a multi-part reactive mixture.
There is frequently a need to dispense a multi-part reactive mixture, for example in the form of a two-part adhesive or sealant. US 555 6007 discloses a dispensing arrangement according to the preamble of claim 1. Other dispensing arrangements are also known from EP 0851217 , US 667 6387 or US 5687815 .
A two-part adhesive or sealant is formed by mixing together two liquid components which react together to provide the adhesive or sealant. The individual components may be stored over a long period of time without deteriorating significantly. When the two components are mixed together, the components react together and an adhesive or sealant having the appropriate properties is created. The adhesive or sealant may cure or set due to the chemical reaction between the two components over a relatively brief period of time.
When dispensing an adhesive or sealant it is sometimes convenient to be able to utilise a hand-held dispensing apparatus.
It has been proposed previously to provide a hand-held dispensing apparatus for a two-part adhesive or sealant. The hand-held apparatus comprises a frame to which is connected a hand-hold and "trigger". The frame supports a cartridge which contains, in two separated chambers, the two components which are to be mixed together. The trigger drives separate pistons into the two chambers forcing the liquid components out of the chambers through an outlet port. A mixer, which may be a so-called static mixer, is connected to the outlet port.
As the pistons are moved, by actuation of the trigger, liquid from each of the two chambers is forced into the static mixture where the two liquids are mixed and are dispensed from an outlet of the static mixer.
Arrangements of this type have operated satisfactorily for many years, but they do have some disadvantages. One disadvantage is that the cartridge can only contain a predetermined relatively small quantity of each of the two liquids. The cartridge may become exhausted relatively quickly, requiring replacement of the cartridge. When a cartridge is replaced the old cartridge has to be disposed of. Thus the manufacture, filling, transportation and eventual disposal of cartridge adds substantially to the overall cost of the operation. The cost can be prohibitive if the hand-held dispenser is being used in a "factory" situation, with substantial quantities of adhesive being dispensed each day.
The present invention seeks to provide an improved liquid dispenser.
According to this invention there is provided a dispensing arrangement for dispensing a two-component mixture, the dispensing arrangement comprising a hand-held unit having at least one handle, the unit incorporating two metering devices, each metering device being provided with an inlet to be connected to a source of liquid under pressure, each metering device having an outlet for metered quantities of liquid, the unit further incorporating flow passages which extend to an outlet port connected to a mixer, there being a mixer connected to the outlet port to mix the two metered liquids and to dispense the mixed liquids, wherein each metering device incorporates an elongate chamber there being a shuttle contained within the chamber, the shuttle having a portion which is a substantially sealing sliding fit within the chamber, the shuttle being moveable axially between an initial position and a second position within the chamber, each end of the chamber being provided with a liquid flow duct through which pressured liquid may enter and leave the chamber, there being valve arrangement to control the flow of liquid to and from the chamber such that, during successive cycles of operation of the metering device, liquid is supplied to one end of the chamber causing the shuttle to move from the initial position at said one end of the chamber to the second position at the other end of the chamber, thus ejecting a predetermined volume of liquid from the other end of the chamber, and subsequently liquid is supplied to said other end of the chamber causing the shuttle to move back from the second position to the initial position, ejecting a pre-determined quantity of liquid from the said one end of the chamber, the valving means comprising a rotary valve rod contained within a valve bore, and a mechanism to rotate the valve rod, the liquid flow ducts from the chamber extending to the valve bore, at least one liquid inlet extending to the valve bore and at least one liquid outlet extending from the valve bore, the valve rod, in combination with the valve bore, defining liquid flow passages which, in one orientation of the valve rod, serve to interconnect a liquid flow inlet and the liquid flow duct extending to one end of the chamber whilst interconnecting the liquid flow duct extending to the other end of the chamber with an outlet and, in an alternate orientation, serving to interconnect the liquid flow inlet with the liquid flow duct extending to the other end of the bore whilst connecting the liquid flow duct extending to the said one end of the bore with an outlet.
Preferably the handle of the unit is associated with a control trigger.
In one embodiment the handle is located beneath the unit.
In another embodiment the handle is located above the unit.
In a further embodiment two handles are provided, the handles being provided on opposed sides of the unit.
Preferably the unit is suspended on a support which applies an up-thrust to the unit substantially equal to the force applied to the unit by gravity.
Conveniently each metering device is connected to a respective source of pressurised liquid.
Advantageously each source of pressurised liquid is a main supply of pressurised liquid capable of supplying a plurality of dispensing devices.
Preferably the mixer is a static mixer.
Preferably each valve rod is rotated by a motor arrangement, the motor arrangement being controlled in response to a signal generated in response to the shuttle of the other metering device reaching an initial position or the second position.
Conveniently each motor arrangement is a stepping motor.
Preferably the shuttle is provided with two rods, each rod extending beyond the chamber, there being a contact or proximity sensor located at the end of each rod, to generate a said signal when the shuttle reaches the initial position or the second position.
Advantageously where adjustable collars are provided on the shuttle rods to limit the movement of the shuttle.
Preferably at least one air bleed is provided communicating with part of each chamber to bleed air from the chamber.
In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a cut-away view of a metering device which is for use in one embodiment of the invention,
FIGURE 2 is a view of the rotary valve rod that forms part of the metering device,
FIGURE 3 is a diagrammatic sectional view illustrating one phase of operation of a device,
FIGURE 4 is a view corresponding to Figure 3 illustrating another phase of operation of the device,
FIGURE 5 is an exploded diagrammatic view of a liquid dispenser arrangement,
FIGURE 6 is a view of the dispenser arrangement of Figure 5 when assembled,
FIGURE 7 is a view of a modified form of liquid dispenser arrangement, and
FIGURE 8 is a view of a further modified form of liquid dispenser arrangement.

Referring initially to Figure 1 of the accompanying drawings, a metering device for use in an embodiment in accordance with the invention comprises a housing 1 which defines a cylindrical chamber 2. Contained within the chamber 2 is a shuttle 3. The shuttle 3 is a unit or assembly which has a central cylindrical portion 4 which is a sliding sealing fit with the chamber 2. The shuttle incorporates two rods 5,6 which extend axially from opposite sides of the cylindrical portion 4 and which pass, as a sliding sealing fit through apertures formed in the end walls of the chamber 2, the rods 5,6 thus projecting beyond the housing. Mounted on the projecting portions of the rods 5,6 are adjustable collars 7,8, the position of which may be adjusted to alter the "stroke" of the metering device as will become clear from the following description. Located adjacent the ends of the rods 5,6 are sensors 9,10 which are responsive to the rods 5,6 each reaching a predetermined position. The sensors may, ideally, be responsive to physical contact of the end of the rod with the sensor.
The central cylindrical portion 4 of the shuttle effectively divides the chamber 2 into two separate parts, one at the left-hand end of the chamber and the other at the right-hand end of the chamber. Respective liquid flow ducts 11,12 connect these end parts of the chamber 2 to spaced-apart points of a cylindrical valve bore 13 defined within the housing 1. Outlet and inlet ducting also communicate with the bore 13. Thus the housing defines a first outlet flow duct 14 offset from the flow duct 11 and second outlet flow duct 15 offset from the flow duct 12. The outlet flow ducts 14 and 15 are off-set axially from the flow ducts 11 and 12, being closer to the ends of the valve bore 13, but one diametrically opposed to the flow ducts 11,12. A liquid inlet flow duct 16 is also defined located at a position between the two liquid flow ducts 11,12. Contained within the cylindrical valve bore 13 is a rotary valve rod 17 which is driven rotationally by a stepping motor M in response to signals from the sensors 9,10.
The rotary valve rod 17 has parts thereof cut away in the form of a channel or recess in the periphery of the rod and passages or bores through the rod so that the rotary valve rod 17, in the cylindrical valve bore 13, may define liquid flow paths. The rotary valve rod 17 is provided with a first through bore 18 which is inclined to the axis of the valve rod 17 and which, in one rotational position of the valve rod 17, when the valve rod 17 is present in the bore, serves to interconnect the liquid flow duct 11 and the first outlet flow duct 14. A second corresponding bore 19 is provided, parallel with the first bore 18, the second bore 19, as will be understood from Figure 2, in an alternate rotational position of the valve rod 17, serves to interconnect the liquid flow duct 12 and the second outlet flow duct 15. Between the two bores 18,19 there is an annular groove 20 formed in the exterior surface of the rotating valve rod 17 which is in alignment with the inlet flow duct 16. The groove 20 is provided with two diametrically opposed axial extensions 21,22, which extend in opposite axial directions. It is to be appreciated that in one rotational position of the rotary valve rod 17 the axial extension 21 will extend to the end of the flow duct 12 thus forming a flow path from the inlet 16 to the right-hand end of the chamber 2, and in an alternate position of the rotary valve rod 17 axial groove 22 will establish communication with the flow duct 11.
Looking now at Figure 3, the shuttle 3 is shown in a right-hand most position with the end of the projecting shuttle rod 6 engaging the sensor 10. As the shuttle rod 6 contacts the sensor 10, so the stepping motor M rotates the valve rod 17 by 180°, thus moving the valve rod 17 to the position as shown in Figure 4.
When the rotary valve rod 17 is in the orientation or the position as shown in Figure 4 the groove 20 and the axial extension 21 serve to connect the inlet 16 to the liquid flow duct 12 which communicates with the right-hand end of the chamber 2, whereas the bore 18 serves to interconnect the liquid flow duct 11 (which, in turn, communicates with the left-hand end of the chamber 2), and the outlet flow duct 14. Pressured liquid may thus flow from the inlet flow duct 16 through the annular groove 20 and the axial extension 21, through the liquid flow duct 12 into the right-hand end of the chamber 2 thus serving to move the shuttle 3 towards the left. As the shuttle 3 moves towards the left, so liquid in the right-hand end of the chamber is discharged through the liquid flow duct 11, and the bore 18 and through the outlet 14. The shuttle 3 thus continues to move towards the left until the shuttle rod 5 contacts sensor 9. When the sensor 9 is contacted, the shuttle 3 has completed its stroke and a pre-determined quantity of liquid in the form of a metered "shot" of liquid has been ejected through the outlet flow duct 14.
In response to a signal generated by the sensor 9 when touched by the shuttle rod 5, the stepping motor M again rotates the valve rod 17 by 180°, thus returning the valve rod 17 to the position or orientation shown in Figure 3. With the valve rod 17 in the position shown in Figure 3 liquid will flow from the inlet through the annular groove 20, the axial extension 22, and through the liquid flow duct 11 to the left-hand end of the chamber 2. The bore 19 in the valve rod 17 interconnects the liquid flow duct 12 and the outlet 15, allowing liquid from the right-hand end of the chamber to flow to the outlet 15. Thus the shuttle 3 will move towards the right until the shuttle rod 6 establishes contact with the sensor 10. As the shuttle makes the movement to the right a pre-determined quantity of liquid, in the form of a metered "shot" of liquid, is ejected from the right-hand part of the chamber 6 through the outlet 15. When the shuttle rod 6 contacts the sensor 10 the motor M is actuated again. The cycle of operation may then repeat.
Since the stepping motor M only rotates the valve rod 17 on receipt of a signal from the sensor 9, or the sensor 10, if the shuttle 3 is not able to complete its stroke, for example due to a lack of liquid, or insufficient liquid pressure, no signal will be given and the metering unit will cease operation. In this way it can be ensured that for each cycle of operation the metering unit delivers an appropriate quantity of liquid, in the form of a correctly metered "shot", which can be of crucial importance if two liquids, which are components of, for example, a two-part adhesive or the like, are to be metered by two separate metering units and mixed in a precisely pre-determined ratio, relative to each other.
It is to be appreciated that the position of the collars 7,8 on rods 5,6 may be adjusted and the position of the sensors 9,10 may be adjusted to increase or decrease the stroke of the shuttle, thus increasing or decreasing the quantity of liquid ejected on each stroke of the shuttle.
As shown in Figures 3 and 4 the chamber 2 may be provided on either side of the cylindrical portion 4 of the shuttle 3, with air bleeds 23, 24. These may be opened to permit air to be discharged from the chamber 2, especially when the described metering device is first filled with the liquid to be metered, to ensure that hydraulic integrity can be established with no compressible air remaining in the chamber 2.
In the described embodiment, the valve is a rotary valve rod, which facilitates manufacture and maintenance of the valve. In use, the valve rod may rotate almost uniformly, avoiding sudden changes of momentum as maybe experienced with a reciprocating valve.
Of course, the metering device as described may be "reversed", with pressurised liquid being supplied to the "outlets" 14,15, and with the "inlet" 16 actually acting as an outlet.
Whilst, in above description of the metering device, reference has been made to contact sensors 9, 10 responsive to contact with the shuttle rods, proximity sensors which respond to the shuttle rods reaching predetermined positions may be used. Also in another alternative embodiment the sensors 9,10 may be annular, with the rods 5 and 6 passing through the sensors, with the sensors 9,10 providing an output signal when contacted by the collars 7 and 8.
Now that a metering device has been described, reference is made to Figure 5 which illustrates an exploded view of one embodiment of the invention. Figure 5 illustrates a hand-held dispenser 30 in an exploded form. The hand-held dispenser comprises a support plate 31 of square or rectangular form. A handle 32 is connected to the under-surface of the support plate 31, the handle 32 being provided with a finger operated trigger 33. Mounted on top of the support plate are two metering devices 34, 35 of the type described above. The metering devices are provided with inlet ports (not shown) which are configured to be connected to supply conduits 36, 37. As will be described hereinafter the supply conduits may extend to a "main" supply of pressurised liquid.
The metering units 34, 35 have outlet ports 38, 39 formed in their upper surfaces. Clampingly engaging the upper surfaces of the metering devices 34, 35 is a liquid transfer housing 40. The housing 40 has two internal passages each of which extend from a point immediately above respective outlets 38, 39 of a metering device, to a combined outlet 42. A plate 43 with a screw-threaded boss 44 is secured to the end wall of the housing 40 adjacent the combined outlet 42. A conventional static mixer 45 as shown in EP 0105181 is secured, by means of a internally threaded collar 46, to the threaded boss 44, so that the mixer is in liquid flow communication with the combined outlet 42.
A motor housing M, containing the motors that drive the pumps, and the control for the motors, extends to the rear of the arrangement.
The fully assembled liquid dispenser 30, as shown in Figure 6, may be suspended, by means of a wire or cable 47 connected to the upper part of the housing, from a support mechanism 48 which includes a resilient retractor. The effect of the retractor is to provide an upward force to the dispenser 30 which is equivalent to the downward force applied by gravity. This facilitates manual operation of the dispenser.
It can be seen that the conduit 36 is connected to a "main" supply conduit 49 and the conduit 37 is connected to a "main" supply conduit 50. It is to be understood that if the hand-held dispenser of Figures 5 and 6 is to be utilised in a factory environment, the factory may be supplied with main supply conduits 49, 50 which are connected to pressurised sources of the appropriate liquids. A large number of hand-held dispensers of the type being described may thus be used within the factory, all being connected to a common supply. This avoids the need for individual drums of the appropriate liquids to be located adjacent each dispenser, and facilitates the provision of the two reactive liquids to a large number of dispensing devices.
In operation of the device, an operative will locate the end of the static mixer 45 at a point where the two-component mixture, such as an adhesive or a sealant, is to be dispensed. The trigger is depressed, which actuates the metering devices 34, 35. The metering devices 34, 35 are controlled by a common controller, which may be located within the housing 40. The controller operates so that the shuttle within the metering device 34 must initially complete a stroke and send a signal to the controller before the valve in the metering device 35 is moved to cause the shuttle in the metering device 35 to complete a stroke. When the shuttle in the metering device 35 has completed a stroke, the controller then actuates the motor of the metering device 34, changing the position of the valve within the metering device 34, so that the shuttle in the device 34 may complete a stroke. The two metering devices thus work sequentially, and should the shuttle of either metering device fail to complete a stroke, the entire apparatus will stop.
The liquid from the metering device 34 flows through the outlet 38 and through the housing 40 to the outlet aperture 42. Similarly liquid from the metering device 35 flows through the outlet 39, through the housing 40 to the outlet aperture 42. The two liquids thus pass through the threaded boss 44 and into the static mixer 45. The liquids are mixed within the static mixer and are dispensed.
If the apparatus is used on a regular basis, with only brief pauses between operations of the trigger, the liquid within the static mixer will only be partly reacted when dispensed, and thus the adhesive or sealant will have adequate properties. Should there be a long delay between operations of the device the liquid within the static mixer may react and set or cure within the mixer. Should this happen, the static mixer is simply removed from the threaded boss 44 and a further static mixer is provided.
If the hand-held device should suffer some mechanical malfunction, the device may be removed from the supply lines 36, 37 and may be replaced by a fresh device, whilst the malfunctioning device is serviced or repaired.
The invention has been described so far with reference to an arrangement in which the hand-held device is provided with a handle beneath the device. Should a handle arrangement of this type be considered to be ergonomically unsound, a handle may be provided on each side of the device, such as handles equivalent to the handle 51 shown in a modified embodiment as illustrated in Figure 7. Alternatively again a handle 52, with an associated trigger 53 maybe provided on the upper part of the dispensing device, as shown in Figure 8.
When used in this Specification and Claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

Claims

A dispensing arrangement for dispensing a two-component mixture, the dispensing arrangement comprising a hand-held unit (30) having at least one handle, and comprising two metering devices (34, 35), each metering device being provided with an inlet (16) to be connected to a source of liquid under pressure, each metering device (34, 35) having an outlet (14, 15) for metered quantities of liquid, the unit further incorporating flow passages which extend to an outlet port (42) connected to a mixer (45), there being a mixer (45) connected to the outlet port to mix the two metered liquids and to dispense the mixed liquids, wherein each metering device (34, 35) incorporates an elongate chamber (2) there being a shuttle (3) contained within the chamber (2), the shuttle (3) having a portion which is a substantially sealing sliding fit within the chamber, the shuttle being moveable axially between an initial position and a second position within the chamber, each end of the chamber (2) being provided with a liquid flow duct (11, 12) through which pressured liquid may enter and leave the chamber, there being valve arrangement (14-22) to control the flow of liquid to and from the chamber (2) such that, during successive cycles of operation of the metering device, liquid is supplied to one end of the chamber (2) causing the shuttle to move from the initial position at said one end of the chamber to the second position at the other end of the chamber, thus ejecting a pre-determined volume of liquid from the other end of the chamber, and subsequently liquid is supplied to said other end of the chamber causing the shuttle to move back from the second position to the initial position, ejecting a pre-determined quantity of liquid from the said one end of the chamber, characterized in that said two metering devices (34, 35) are incorporated in said hand-held unit (30), and in that the valving means (14, 22) comprise a rotary valve rod (17) contained within a valve bore (13), and a mechanism to rotate the valve rod (17), the liquid flow ducts (11, 12) from the chamber (2) extending to the valve bore (13), at least one liquid inlet (16) extending to the valve bore and at least one liquid outlet (14, 15) extending from the valve bore (17), the valve rod (17) in combination with the valve bore (17), defining
liquid flow passages which, in one orientation of the valve rod, serve to interconnect a liquid flow intet (16) and the liquid flow duct (11) extending to one end of the chamber whilst interconnecting the liquid flow duct (12) extending to the other end of the chamber with an outlet (15) and, in an alternate orientation, serving to interconnect the liquid flow inlet (16) with the liquid flow duct (12) extending to the other end of the bore whilst connecting the liquid flow duct (11) extending to the said one end of the bore with an outlet (14).
An arrangement according to Claim 1 wherein the handle of the unit is associated with a control trigger.
An arrangement according to Claim 1 or 2 wherein the handle is located beneath the unit.
An arrangement according to Claim 1 or 2 wherein the handle is located above the unit.
A arrangement according to Claim 1 or 2 wherein two handles are provided, the handles being provided on opposed sides of the unit.
An arrangement according to any one of the preceding Claims wherein the unit is suspended on a support which applies an up-thrust to the unit substantially equal to the force applied to the unit by gravity.
An arrangement according to any one of the preceding Claims wherein each metering device is connected to a respective source of pressurised liquid.
An arrangement according to Claim 7 wherein each source of pressurised liquid is a main supply of pressurised liquid capable of supplying a plurality of dispensing devices.
An arrangement according to any one of the preceding Claims wherein the mixer is a static mixer.
An arrangement according to any one of Claims 1 to 9 wherein each valve rod is rotated by a motor arrangement, the motor arrangement of each valve rod being controlled in response to a signal generated in response to the shuttle of the other metering device reaching an initial position or the second position.
An arrangement according to Claim 10 wherein each motor arrangement is a stepping motor.
An arrangement according to any one of Claims 1 to 11 wherein the shuttle is provided with two rods, each rod extending beyond the chamber, there being a contact or proximity sensor located at the end of each rod, to generate a said signal when the shuttle reaches the initial position and the second position.
An arrangement according to Claim 12 wherein adjustable collars are provided on the shuttle rods to limit the movement of the shuttle.
An arrangement according to any one of Claims 1 to 14 wherein at least one air bleed is provided communicating with part of each chamber to bleed air from the chamber.