Method and apparatus for dispensing flowable materials

Abstract

 A dispensing device (10) for a beverage component dispensing machine comprises a solenoid operated valve (20) in which the valve-open position of the valve is defined by an equilibrium condition of the solenoid (22) with its armature, acting against a return spring (44), whereby solenoid generated noise in the valve-open condition is reduced. The solenoid armature (34) is position-adjustable with respect to the valve member to vary the valve opening. The armature and the valve member are supported in the valve open condition in the manner of a pendulum through the return spring which is adjustably connected to the valve, whereby the valve-open equilibrium position of the armature is laterally as well as vertically balanced.

Description

[0001] This invention relates to a method and apparatus for use in beverage and beverage component dispensing machines for dispensing flowable materials, and to beverage dispensing machines incorporating same. An example of the application of the invention is to devices for dispensing tea, coffee, milk, cocoa, sugar and other dry flowable beverage component materials. The invention is also applicable to dispensing liquid beverages and liquids used in beverages.

[0002] Previous proposals in this field such as GB 1518796 include devices for dispensing tea, coffee, etc., in which a solenoid operated valve controlling material flow is arranged so that the degree of valve opening is controlled by adjustable stop means which limits the travel of the solenoid and in this way limits the movement of the valve member in its opening direction. It will be understood that in this field it is essential that the degree of valve opening is well controlled so that the amount of material dispensed is likewise well controlled. In this prior proposal, the armature of the solenoid is mounted for centralised sliding movement in spaced parallel guide members.

[0003] The shortcomings of the prior art mentioned above include the noise generated by the solenoid during dispensing. This is particularly unacceptable for beverage dispensing machines for use in offices. Also, the valve assembly tends to jam during use. Moreover, the valve assembly comprises many individual components and thus is relatively expensive to manufacture and maintain.

[0004] An object of the present invention is to provide improvements in relation to one or more of the shortcomings of the prior art as discussed above, or generally.

[0005] According to the invention there is provided a method and apparatus for use in a beverage dispensing machine for dispensing flowable material, as defined in the accompanying claims.

[0006] In an embodiment described below there is provided a method and apparatus for dispensing fluid media under external control. The latter control can be manual,mechanical, electronic, electrical, or any combination of these. The device operates as follows. An electrical potential difference is applied to the field winding of a solenoid. This creates a magnetic field which attracts the armature thereof. The armature is attached to a valve member which opens as the armature is moved, thereby allowing fluid media to pass through an associated valve seat from a hopper into a funnel. When the solenoid is de-energised, a return spring returns the valve to its closed condition. The primary use of the apparatus is for dispensing powders used in beverage dispensing machines.

[0007] Also in the embodiment, the valve member is arranged to be self-centring by means of single point mounting on a bridge support member. This removes the need for critical alignment of the assembly during manufacture, and readjustment during use. The armature of the solenoid is allowed in use to find its own centre position. The armature is lengthwise adjustable on the stem of the valve assembly. Adjustment is by screw means. The setting determines the distance that the valve opens away from its seat during use, and this likewise determines the amount of flowable material that is allowed to pass in a given time.

[0008] In the embodiment, because the armature is allowed to find its own centre position, of equilibrium, and this defines the valve open condition of the valve, this makes for extremely quiet operation as compared with those solenoids which work against a stop, which emit an annoying buzzing noise during dispensing, which is unacceptable in offices. By avoiding the use of a stop to define the valve open position and by providing alternative means for adjusting the valve in this position, this problem is avoided in the embodiment. Also in the embodiment, a return spring for the valve assembly is provided. The connection of the spring to the valve stem is adjustable, thereby enabling adjustment of the spring compression to compensate for wear. The embodiment can be manufactured in any size to suit particular applications. Moreover, the valve member and the valve seat can be made as one piece mouldings. The absence of an adjusting mechanism at the top of the valve stem assembly means that there is little to impede the flow of material from the supply into the receptacle.

[0009] In the embodiment, the solenoid operated valve moves to the end position of the solenoid on energising same. By providing means to adjust the solenoid with respect to the valve member, the end position of the solenoid can be adjusted to suit the degree of opening required for the valve. By supporting the valve member in the magnetic field of the solenoid with freedom to swing laterally, the armature of the solenoid can adopt an equilibrium position, and indeed always does so in use. This avoids the problems of the prior art in which misalignment of the solenoid with respect to its support and guides produces jamming in use. This arises particularly from abuse of the machine by users attempting to cause it to dispense without (for example) inserting the necessary coin.

[0010] An embodiment of the invention will now be described by way of example with reference to the accompanying drawing which shows a sectioned elevation view of a device for dispensing flowable materials, such as beverage powder, in a beverage dispensing machine.

[0011] As shown in the drawing, a beverage dispensing machine 10 comprises a reservoir or hopper 12 for flowable material such as powdered tea or coffee or cocoa or sugar or the like. This ingredient hopper has a base wall 14 formed with a central circular opening 16 through which material from the hopper can flow into a funnel 18 for delivery below into a drinking vessel ( not shown ).

[0012] To control the flow of material from the hopper 12 into funnel 18 there is provided a valve assembly 20 operated by a solenoid 22. Operation of solenoid 22 causes a valve member 24 to move in the generally up and down direction to open and close the valve. The valve member seats against the opening 16 in the base wall 14 of the hopper.

[0013] Valve member 24 has a generally frusto-conical valve-­seating surface 26 which seats against opening 16. The valve member also comprises upper and lower valve stem portions 28 and 30 respectively. The lower stem portion is formed with a screw thread 32 on which the armature or field response member 34 of solenoid 22 is screw-threadedly received for position-adjustment lengthwise of the stem portion 30. The armature 34 is controlled by the solenoid field winding 36 which is electrically energised in the usual way.

[0014] The upper valve stem portion 28 is of smaller diameter than portion 30 and extends freely and slidably through a bridge or support structure 38 comprising legs 40,42 between which the powder to be dispensed freely flows to opening 16. The support 38 is mounted on hopper base 14 and supports the valve member through a return spring 44 which is connected to stem 28 through a clip 46 which frictionally grips the stem but is manually position adjustable to adjust spring compression for wear.

[0015] As can now be seen, valve member 24 is caused in its position of rest to be held by return spring 44 in the closed position shown in the drawing with surface 26 sealing valve opening 16.

[0016] On energising solenoid field winding 36, the solenoid armature 34 is urged by the magnetic field generally downwards so as to open the valve against the action of return spring 44. The valve member freely slides through bridge 38 until it reaches a position of equilibrium. In this position it is supported from bridge 38 through spring 44 at a single point, namely the apex of the bridge. The armature 34 is thus free to swing laterally from this point of suspension so that it can take up its position of equilibrium in the magnetic field with two degrees of freedom, namely up and down and lateral or sideways movement. Indeed, as the armature moves to its position of equilibrium or rest in the energised field, so this movement opens the valve to a predetermined extent. On de-­energising the field, return spring 44 causes the valve to close and the flow of material which commenced on opening the valve then ceases.

[0017] In order to adjust the dispensing apparatus to produce the required quantity of material in a given beverage cup, all that is needed is to adjust armature 34 lengthwise on stem portion 30. Finger grip formations may be provided on the armature for this purpose. The armature will always adopt substantially the same end position in the field of winding 36, but according to its adjustment on stem portion 30, the degree of valve opening will vary. This simple mechanical adjustment is easy and safe for the user to effect.

[0018] Because the valve member and its armature are supported throug a spring from the single location provided by the top of bridge structure 38, the armature can adopt a position of equilibrium freely within the solenoid field and thereby avoids the generation of noise in its energised, valve-open position, which has been a problem with prior art apparatus.

[0019] Many modifications could be made in the above embodiment while remaining within the scope of the invention, these including the mode of adjusting the armature relative to its valve stem portion, and details of the return spring arrangements and the supporting of the valve assembly on the hopper. Instead of screw threaded adjustment, a friction fit adjustment could be provided, or stepwise adjustment by means of grooves, holes or other formations on the rod and co-operating clips or pins or pegs etc on the armature. With suitable seals such as O-­rings the apparatus could dispense liquids, such as soft drinks and other beverages.

[0020] Interestingly, in the embodiment, the provision of a solenoid armature which is length adjustable relative to the valve member provides significant advantages, particularly in relation to solenoid-generated noise, by permitting simple manual adjustment of the degree of valve opening and thus of the rate dispensing during a given dispensing period. Likewise the ability of the solenoid armature to adopt its own position of equilibrium or rest while being resiliently supported from the single point above in the manner of a pendulum likewise reduces noise generation and simplifies assembly and avoids the problems of jamming which have hitherto existed.

Claims

1. A device for use in beverage and beverage component dispensing machines for dispensing a flowable beverage or beverage component from a supply into a receptacle therefor, comprising a valve having a valve member and a valve seat to control the flow of said material from said supply, and an electrically operated control mechanism to operate said valve, said control mechanism comprising magnetic field means and a magnetic field response member positioned for actuation by said field and connected to said valve member to actuate same, characterised by said valve member being position adjustable with respect to said magnetic field response member whereby the extent of opening of said valve is determined by reference to an equilibrium position of said said magnetic field response member with respect to said field in the energised condition of said control mechanism.

2. A device according to claim 1 characterised by said valve member being spaced from said magnetic field response member and connected thereto by rod means or the like and said magnetic field response member is lengthwise position-adjustable on said rod means or the like.

3. A device according to claim 1 or claim 2 characterised by resilient return means to close said valve, said resilient return means being adjustably connected to said valve to vary the valve closing force thereof.

4. A device for use in beverage and beverage component dispensing machines for dispensing a flowable beverage or beverage component from a supply into a receptacle therefor comprising a valve having a valve member and a valve seat to control the flow of said material from said supply, and an electrically operated control mechanism to operate said valve, said control mechanism comprising magnetic field means and a magnetic field response member positioned for actuation by said field and connected to said valve member to actuate same, characterised by said valve member being mounted on a rod or the like connecting it to said magnetic field response member, said rod being mounted on a support through spring means which permits lengthwise movement of the rod to open and close the valve, and said field response member also being free to adopt its own position with respect to said magnetic field, at least in the valve open condition, by lateral movement with respect to the lengthwise direction of said rod.

5. A device for dispensing flowable material according to any one of the preceding claims in the form of a device for dispensing beverage components in a beverage dispensing machine.

6. A beverage dispensing machine comprising a device for dispensing flowable material according to any one of the preceding claims.

7. A method of dispensing a beverage or one of more components thereof comprising energising an electrically operated control mechanism to open a dispensing valve and maintain same in its open condition for an interval of time, said valve open position being defined by means connected to said valve, characterised in that in said valve open position a magnetic field response member of said control means is in equilibrium with magnetic field means thereof, and said equilibrium condition of said magnetic field response member and said magnetic field means constitutes said means defining said valve open position.

8. A method according to claim 7 characterised by the step of position-adjusting said magnetic field response member with respect to a valve member of said dispensing valve to adjust the degree of opening of said dispensing valve.

Drawing