Patent Description:
Peristaltic pumps are a type of positive displacement pump used for pumping a variety of fluids. A typical peristaltic pump comprises a flexible tube for conveying the fluid through compression of the tube in a peristaltic manner. Fluid is pushed or pulled through the tube by moving the region of compression along the length of the tube. Compression of the tube is typically achieved by mechanically driven rollers which pinch off a section of the tube. A typical peristaltic pump thus comprises a plurality of rollers between which fluid is trapped: as the rollers rotate, the trapped fluid is transported through the tube towards the pump outlet. Peristaltic pumps are often used where the flow of fluid needs to be carefully metered, i.e. where small amounts of fluid need to be accurately delivered. Peristaltic pumps are thus widely used in medical applications, for example for delivering IV fluids to patients, and food and beverage applications.

However, typical peristaltic pumps can suffer from problems with the accuracy of fluid dosing. For example, some peristaltic pumps can suffer from flat spots in fluid delivery, and pulsating fluid delivery.

The present invention seeks to provide a peristaltic pump with improved accuracy of fluid delivery compared to prior art pumps. <CIT> discloses a peristaltic pump comprising a fluid inlet and outlet; a carrier member having an outer surface; flexible tubing for conveying a fluid which extends at least partially around the outer surface of the carrier member; and a drivable compression roller; wherein the carrier member and compression roller can be positioned adjacent one another to compress the flexible tubing there between.

Thus, according to the present invention there is provided a peristaltic pump comprising:.

The peristaltic pump of the present invention thus conveys fluid using the same principles as a conventional peristaltic pump, i.e. fluid is conveyed along flexible tubing by compressing the flexible tubing and moving the point of compression along the flexible tubing. However, in the peristaltic pump of the present invention, unlike a conventional peristaltic pump, rollers do not rotate about an internal central axis relative to flexible tubing which is fixed in position, for example within and relative to a housing or manifold. Instead, in the pump of the present invention the flexible tubing moves relative to the compression roller, through rotation of the carrier member about its rotational axis, on which the flexible tubing is positioned, driven by rotation of the compression roller. Thus, in use when the compression roller and carrier member are positioned to convey fluid through the flexible tubing, with the flexible tubing compressed therebetween, the axis of rotation of the carrier member and the axis of rotation of the compression roller/flexible tubing are in fixed positions relative to each other. In this way, greater accuracy of fluid delivery can be achieved compared to conventional peristaltic pumps. For example, the compression roller may have a circumference substantially smaller than that of the carrier member, meaning that rotation of the compression roller through a full <NUM>° rotation corresponds to rotation of the carrier member, and hence the flexible tubing, through only a fraction (arc) of the circumference of the carrier member. For example, the ratio of the circumference of the compression roller to the carrier member may be from <NUM>:<NUM> to <NUM>:<NUM> or <NUM>:<NUM>, meaning that, for these ratios, a full <NUM>° rotation of the compression roller would rotate the carrier member through <NUM>°, <NUM>° and <NUM>° respectively. This arrangement allows for very accurate control of the amount of fluid being conveyed through the flexible tubing. However, the relative sizes of the compression roller and carrier member are not limited, and may be selected as desired according to the requirements of the pump.

The peristaltic pump of the present invention thus comprises a carrier member having an outer surface on which the flexible tubing is positioned and extends at least partially around. The carrier member preferably takes the form of a rotatable wheel with the flexible tubing positioned around its outer circumference. For example, the carrier member may comprise circumferential flanges between which the flexible tubing may be positioned. The flanges may have a depth which is equal to or less than the thickness of the flexible tubing material. The flexible tubing preferably extends around the carrier member as a single turn coil.

The flexible tubing used in the peristaltic pump of the present invention may be formed of any material which is suitable for the intended purpose of the pump, and in particular the fluid to be conveyed. For example, suitable materials may include polyvinyl chloride, silicone, polyurethane and natural rubber. For example, for delivery of a beverage or a beverage ingredient, a preferred material is silicone. The thickness of the tubing material may also be selected according to requirements, for example to be equal to or greater than the depth of circumferential flanges of the carrier member.

In use, fluid enters the pump through the inlet from a fluid source, such as a fluid reservoir or container. Thus, the pump may comprise an inlet pipe or tube for insertion into a fluid reservoir through which fluid may be drawn into the pump through the flexible tubing.

As described herein, in use the flexible tubing moves relative to the rotational axis of the compression roller as the carrier member rotates, driven by the compression roller. Thus, in use the flexible tubing rotates with the carrier member about its rotational axis. To allow the flexible tubing to rotate in this way without twisting, the flexible tubing may be connected to the pump outlet via a fluid-tight movable joint, such as a rotary joint, to allow relative movement between the flexible tubing and the pump outlet. Thus, in an embodiment of the pump of the present invention, the fluid flow path may comprise an inlet comprising a pipe or tube which in use is in fluid communication with a fluid source and also with the flexible tubing, and the flexible tubing extends from the inlet around the circumference of the carrier member to the pump outlet via a fluid-tight movable joint, such as a rotary joint. The flexible tubing may be connected to the pump inlet by a movable joint, such as a rotary joint.

The pump of the present invention further comprises a drivable compression roller positionable relative to the carrier member so as to compress the flexible tubing between the compression roller and carrier member. The compression roller is rotatable about an axis of rotation, and is preferably driven by a rotary drive, such as an electric motor. The compression roller is preferably rotatable in opposite directions, i.e. both forwards and backwards. In this way, the compression roller can be driven in a first direction to dispense fluid from the reservoir to a desired location through the flexible tubing, and can be driven in a second, opposite direction to allow fluid in the flexible tubing to be returned to the fluid reservoir. Driving the compression roller in the second direction also allows a cleaning fluid, such as water, to be drawn into the flexible tubing to clean the flexible tubing and thus help to prevent cross-contamination if the pump is being used to deliver a plurality of different fluids.

The compression roller preferably takes the form of a wheel or cylinder, and may have a circumference which is substantially smaller than the circumference of the carrier member. In this way, a full <NUM>° rotation of the compression roller corresponds to rotation of the carrier member, and hence the flexible tubing, through only a small fraction (arc) of the circumference of the carrier member. The specific gearing, i.e. relative sizes of the compression roller and carrier member, to be used in a particular pump will depend upon the intended use of the pump. Thus, a smaller diameter compression roller relative to the carrier member will provide greater accuracy in fluid delivery, but will require a greater degree of or number of rotations to deliver the same amount of fluid as a compression roller having a greater diameter relative to the carrier member. The thickness/depth of the compression roller may be selected according to the corresponding dimensions and configuration of the carrier member and flexible tubing. For example, if the carrier member comprises circumferential flanges to retain the flexible tubing in position then the compression roller may have a thickness/depth selected so the compression roller sits between the flanges to compress the flexible tubing. Alternatively, the compression roller may take the form of an elongate cylinder which can press against the flanges to compress the flexible tubing within the flanges, for example where the flexible tubing is formed from a material which has a thickness equal to or greater than the depth of the flanges. The pump of the present invention may comprise more than one compression roller, radially circumferentially spaced around the carrier member, according to the requirements of the pump. All, some, or only one of the compression rollers may be drivable, for example by an electric motor.

During operation of the pump it is possible that continuous flow of fluid through the flexible tubing may be interrupted due to gaps or "dead spots" in which fluid is absent from the flexible tubing. These dead spots may be more prevalent at points of greater curvature of the flexible tubing, for example where the flexible tubing first comes into contact with the carrier member downstream of the inlet, and where the flexible tubing leaves the carrier member going towards the outlet. To help ensure that the desired amount of fluid is delivered by the pump, the pump may be configured to recognize any dead spots, for example using a microswitch, and adjust the run of the motor accordingly to take the dead spot(s) into account.

The pump of the present invention may be used to accurately deliver small amounts of fluid in different applications, such as medical applications, or food and drink applications. For example, the pump may be used to dispense a beverage or beverage ingredient, such as a flavouring, vitamin, fibre, or caffeine. The pump may be configured to dispense the fluid, for example beverage or beverage additive, in a predetermined amount, for example by driving the compression roller for a predetermined length of time, preferably adjusted to take into account any interruptions in fluid flow due to dead spots, as discussed above.

The pump of the present invention may form part of a fluid delivery system for delivery of a fluid from a fluid reservoir to a desired location. For example, the pump may be located in a housing with a fitting for attachment to a fluid reservoir. Thus, a fluid delivery system may comprise a housing having a fitting to which a fluid reservoir may attached, such as by a screw- or push-fit. The housing may be openable and closable to allow for removal and replacement of a fluid reservoir. In embodiments, the carrier member of the pump may be formed integrally with a fitting for attachment to a fluid reservoir, which is removable from the fluid delivery system for replacement of the fluid reservoir. In these embodiments, the carrier member, fitting and/or fluid reservoir may all rotate together as a unit when the carrier member is rotated by the compression roller. The fluid delivery system preferably comprises a motor for driving the pump. The fluid delivery system preferably comprises a fluid inlet, such as a tube or pipe, attached to the flexible tubing inlet, which in use is inserted into the fluid in the fluid reservoir when the fluid reservoir is attached to the housing. The fluid delivery system preferably further comprises a fluid outlet, such as a nozzle, tap, dropper or mixer, attached to the flexible tubing outlet, for delivery of the fluid to the desired location. In embodiments, the fluid delivery system outlet may comprise mixing means by which different fluids from different fluid reservoirs may be mixed on delivery to a desired location. For delivery of a beverage or beverage ingredient, the fluid delivery system may comprise a platform on which a beverage receptacle, such as a glass or bottle, may be placed so as to be positioned directly below the fluid outlet for delivery of the fluid into the receptacle.

The fluid delivery system may comprise flow prevention means, for preventing flow of fluid from the system, for example when a fluid reservoir is being replaced. Unwanted flow of fluid may be messy and present hygiene issues. The flow prevention means may comprise a clamp for clamping or pinching the flexible tubing to prevent fluid from exiting. The flow prevention means may comprise a clamp for clamping or pinching the flexible tubing to prevent fluid from exiting. In embodiments where the fluid reservoir is replaced by opening the housing of the fluid delivery system, the flow prevention means may be activated whenever the housing is opened, thereby clamping or pinching the flexible tubing to prevent fluid flow whilst the housing is open, releasing the flexible tubing when the housing is closed.

The fluid delivery system may comprise a controller, such as a programmable computer, for controlling fluid delivery. For example, the controller may be pre-programmed to deliver a predetermined amount of fluid or may deliver fluid in an amount determined by a user input, for example via user input means such as a touchscreen. The controller may control fluid delivery based upon other inputs from the system, for example in response to sensor inputs recognizing dead spots in fluid flow, e.g. from a microswitch, and adjust the run of the motor accordingly to take the dead spot(s) into account. The controller may comprise a computer memory for storing different user profiles each having particular fluid delivery preferences for that user. The controller may comprise wireless technology, e.g. smart technology, so as to be controllable by a user remotely (e.g. a smartphone app). The computer memory may be configured to store other information, such as the use history of the fluid delivery system, service history, and so forth.

The fluid delivery system may be useable with a plurality of fluid reservoirs simultaneously. Thus, for delivery of a beverage or beverage ingredient, the fluid delivery system may be able to deliver a plurality of different beverages or beverage ingredients, for example different flavourings, without a user needing to replace the fluid reservoir. The fluid delivery system may comprise a single pump according to the present invention which is in fluid communication with each of a plurality of fluid reservoirs, or may comprise a plurality of pumps. For example, the fluid delivery system may comprise a plurality of pumps each of which is for use with a separate fluid reservoir. The fluid delivery system outlet may comprise, for example, mixing means for allowing a plurality of different fluids from different fluid reservoirs to be delivered mixed together.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings in which:.

Common reference numbers are used for the same features in each of the Figures. Not all features of the illustrated embodiments of the invention are shown in each of the Figures.

Referring to <FIG>, a pump (generally indicated by reference <NUM>) according to the present invention is shown comprising a fluid inlet (not shown) and outlet <NUM>. A further section of flexible tubing (not shown) will typically be attached to the outlet <NUM> to convey fluid from the pump <NUM> to the desired location. The pump <NUM> comprises a carrier member <NUM> and flexible tubing <NUM> extending around the outer surface of the carrier member <NUM> in a single turn. The pump <NUM> also comprises a drivable compression roller <NUM> which is shown in <FIG> and <FIG> positioned against the carrier member <NUM> to compress the flexible tubing <NUM> therebetween. The compression roller <NUM> comprises an elongate cylinder and is rotated by a motor <NUM> to thereby cause the carrier member <NUM> and flexible tubing <NUM> to rotate, by which fluid within the flexible tubing <NUM> can be conveyed along the flexible tubing <NUM> through peristaltic action. Also shown are a fluid reservoir <NUM> which attaches to the carrier member <NUM> through a fitting <NUM>, and a pump housing (generally indicated by reference <NUM> without a cover). The carrier member <NUM> engages with the housing <NUM> through engagement member <NUM>, which projects from the upper surface of the carrier member <NUM>. The engagement member <NUM> engages with a slot <NUM> (see <FIG> and <FIG>) in the underside of the housing <NUM> and is free to rotate within the slot <NUM> when the pump <NUM> is in use. In the embodiment shown in <FIG>, the carrier member <NUM>, flexible tubing <NUM>, fitting <NUM> and fluid reservoir <NUM> form a single unit, as shown in <FIG>, which is detachable from the pump housing <NUM>, as is more fully described below with reference to <FIG>. <FIG> also shows flow prevention means <NUM>, for clamping a section of flexible tubing downstream of the pump outlet <NUM> for preventing fluid flow from the pump <NUM>, for example when a fluid reservoir <NUM> is being replaced. The flow prevention means <NUM> is described further in more detail below with reference to <FIG>.

The motor <NUM> is able to drive the compression roller <NUM> both forwards and backwards, to dispense fluid to a desired location in a first direction, and in the second, opposite direction to allow fluid in the flexible tubing <NUM> to be returned to the fluid reservoir <NUM>. Driving the compression roller <NUM> in the second direction also allows a cleaning fluid, such as water, to be drawn into the flexible tubing <NUM> to clean the flexible tubing <NUM> and thus help to prevent cross-contamination if the pump <NUM> is being used to deliver a plurality of different fluids.

<FIG> shows an enlarged view of the carrier member <NUM> and fitting <NUM>. Thus, the carrier member <NUM> is shown to have circumferential flanges <NUM> defining a circumferential channel <NUM> in which the flexible tubing <NUM> (not shown in <FIG>) is carried by the carrier member <NUM>. <FIG> also shows an inlet tube <NUM> which extends within the fluid reservoir <NUM> (not shown in <FIG>) through which fluid enters the fluid delivery device.

<FIG> show the connections between the inlet tube <NUM>, flexible tubing <NUM>, carrier member <NUM> and outlet <NUM> in more detail. Thus, the elongate inlet tube <NUM> has an inlet end <NUM> which extends within the fluid reservoir <NUM> (not shown) and an outlet end <NUM> which connects to the inlet of the flexible tubing <NUM> at inlet junction <NUM>. The flexible tubing <NUM> extends in a single coil around the circumference of the carrier member <NUM> within channel <NUM> defined by flanges <NUM>. The flexible tubing outlet <NUM> connects to a movable rotary joint <NUM> at outlet junction <NUM>. The movable rotary joint <NUM> is positioned within the engagement member <NUM> and is in fluid-tight communication with the pump outlet <NUM> through O-ring <NUM>. The movable rotary joint <NUM> allows for relative rotation between the flexible tubing <NUM> about the rotational axis of the carrier member <NUM> and the outlet <NUM>, to allow the outlet <NUM> to remain in a fixed position as the carrier member <NUM> rotates. <FIG> also shows screw threads <NUM> by which the fitting <NUM> attaches to the fluid reservoir <NUM> (not shown in <FIG>).

<FIG> show how a fluid reservoir <NUM> may be detached from the housing <NUM>, for example to replace an empty reservoir <NUM>. Thus, <FIG> shows the fluid reservoir <NUM> attached to the housing <NUM>, with the housing <NUM> in a closed position. <FIG> shows the housing <NUM> in an open position, in which the outlet <NUM> is detached from the movable rotary joint <NUM> within the carrier member <NUM>. <FIG> shows the engagement member <NUM> held within the slot <NUM> on the underside of the housing <NUM>. When the housing <NUM> is in the open position, the engagement member <NUM> may be removed from the slot <NUM> and the unit comprising the carrier member <NUM> and fluid reservoir <NUM> may be removed as shown in <FIG>.

<FIG> also illustrate operation of the flow prevention means <NUM>. As shown, the flow prevention means comprises a clamp through which a further section of flexible tubing (not shown) for conveying fluid from the outlet <NUM> to the desired location would be held. When the housing <NUM> is in the closed position, as shown in <FIG>, the flow prevention means is not activated and the flexible tubing is unconstricted within the flow prevention means <NUM> so that fluid can be conveyed therethrough. However, when the housing <NUM> is in the open position, as shown in <FIG> and <FIG>, the flow prevention means moves upwards relative to the flexible tubing, which causes a constriction within the flexible tubing and thereby prevents fluid from flowing within the flexible tubing whilst the housing <NUM> is in the open position. When the housing <NUM> is returned to the closed position, as shown in <FIG>, the flow prevention means <NUM> returns to the non-activated position, and fluid can once again flow through the flexible tubing.

<FIG> and <FIG> show an array <NUM> of seven individual fluid delivery systems <NUM> according to the present invention, features of which are described with reference to <FIG>. In this embodiment, each of the individual fluid delivery systems <NUM> is identical, and thus for ease of reference, reference numerals are provided in each Figure for one individual fluid delivery system <NUM> of the array <NUM> only. However, it will be understood that each of the individual fluid delivery systems <NUM> has the same features.

Thus, the illustrated embodiment of a fluid delivery system array <NUM> comprises seven individual fluid delivery systems <NUM>, each of which comprises a fluid reservoir <NUM>, a housing <NUM> and housing cover <NUM>, and pump <NUM>. However, it is to be understood that the fluid delivery systems <NUM> may be used individually, or in an array containing any desired number of fluid delivery systems <NUM>. The housings <NUM> are shown having covers <NUM>. The array <NUM> is held within a casing <NUM> which comprises a backplate <NUM> and a front plate <NUM>. The casing <NUM> also comprises platforms <NUM> upon which the fluid reservoirs <NUM> rest when the units comprising the carrier member <NUM> and fluid reservoirs <NUM> are attached to the housings <NUM>.

A fluid delivery system array <NUM> allows for a plurality of different fluids to be delivered to a desired location. For example, in the case of beverages, each of the fluid reservoirs <NUM> may contain a different beverage or beverage additive, such as a flavouring. Each fluid delivery system <NUM> is in fluid communication with an outlet for delivering fluid to a desired location, for example by flexible tubing. Each fluid delivery system <NUM> may be individually and separately in fluid communication with the outlet, or a plurality of fluid delivery systems may be commonly in fluid communication with the outlet, for example through a shared flexible tubing. As discussed herein, in the illustrated embodiment, each of the individual fluid delivery systems <NUM> of the array <NUM> has its own pump <NUM>, but a plurality of fluid delivery systems <NUM> may share a common pump <NUM>.

Claim 1:
A peristaltic pump (<NUM>) comprising:
a fluid inlet and outlet (<NUM>);
a carrier member (<NUM>) having an outer surface;
flexible tubing (<NUM>) for conveying a fluid which extends at least partially around the outer surface of the carrier member; and
a drivable compression roller (<NUM>);
wherein the carrier member and compression roller are positioned adjacent one another to compress the flexible tubing therebetween;
characterized in that the compression roller is rotatable about an axis of rotation to thereby cause the carrier member and flexible tubing to rotate about an axis of rotation, by which fluid within the flexible tubing can be conveyed along the flexible tubing between the inlet and outlet.