AU2002214052C1 - Device for emptying a food storage container which can be sealed by means of a valve - Google Patents

Abstract

The invention relates to a device for emptying food storage containers. The invention is characterised in that the device is embodied as an attachment (1) for a hand-held electrical household appliance, particularly a rod mixer and comprises a vacuum pump (17). The invention also relates to a method for emptying a food storage container, whereby an attachment comprising a vacuum pump is disposed on a rod mixer. The inventive attachment is advantageous in that it is provided with a small, economical and easy to handle vacuum pump for use in the household. In contrast to prior art no completely new household appliance with corresponding additional storage requirements needs to be added. The inventive attachment is simple and safe to use in the household.

Description

WO 02/46044 Al PCT/EP01/13147 06499 Device for Evacuating a Food Storage Container Closable by a Valve This invention relates to a device in accordance with the prior-art portion of patent claim 1.

The art knows of systems for storing food which allow the food to be preserved under better framework conditions than if it were stored without any treatment or improved storage conditions. One way to improve the storage of food is to keep it in containers under vacuum.

.Such systems have been shown to produce very good results in preventing certain microorganisms, insect pests, mold and fungus growth. Furthermore, they help to prevent the food from oxidizing, thereby enabling variations in the moisture content and aroma of the food to be :i 10 avoided.

To obtain such storage conditions a device is necessary which draws air out of the storage container in order to generate a vacuum. A wide variety of pumps for performing this function are known from the art. As a rule the pumps intended for household use are based on piston pumps or ventilators.

U.S. Pat. No. 5,195,427 discloses a prior-art electrically powered handheld vacuum pump for use in the household. The handheld device is constructed from a multiplicity of single parts for use solely as a vacuum pump. In particular provision is made for an elaborate conver-.

sion of the shaft's rotary'motion into an oscillating motion and for a suitable reduction gear to drive the piston pump. The system is intended for the evacuation of storage containers for food.

With this device it is possible by easy means to obtain a suitable pressure ratio for storing food in a vacuum container.

From DE 195 04 638 Al there is known an immersion blender for mixing or comminuting food whose blade rotates in a bell-shaped recess, thereby generating a vacuum which is produced via a fluid connection from the upper part of the shank of the immersion blender. The vacuum accumulating in the bell serves to improve and intensify the mixing of food.

From German utility model 299 20 316 U1 there is known a device for generating a vacuum in a container, using a vacuum-cleaner as a vacuum generator. For this purpose use is made of an adapter piece in the form of an attachment to a vacuum-cleaner, which is mountable on a valve arranged on the lid of the container. Handling the vacuum generator constructed as P:\WPDOCS\CAB\SPECI\7817703.doc-27/01/05 -2c', a vacuum-cleaner is elaborate and complicated. Problems of hygiene may arise when dealing with 00 C food.

The electric vacuum pumps introduced for household use are very elaborate to manufacture because rod mechanism and gearing require a large number of components. The structural configuration results moreover in relatively large dimensions of the equipment.

(Ni Furthermore, purchasing a corresponding vacuum pump means that an additional household appliance has to be stored but is used in only a few cases.

(Ni It is therefore an object of the present invention to provide a device for the evacuation of storage containers for food which affords ease and greater economy of manufacture.

According to one aspect of the present invention there is provided an attachment device for a handheld electric appliance, in particular an immersion blender or hand mixer having a drive shaft the attachment device being for evacuating a food storage container closable by a valve, the device including a vane type vacuum pump adapted to be driven by a rotary motion, a shaft coupling directly connectable to the drive shaft of the household appliance and adapted to actuate the vacuum pump so that the vacuum pump can be driven with the rotational frequency of the drive shaft.

The attachment of the invention for a handheld electric household appliance has the advantage of providing a small, low-cost and easy-to-use vacuum pump for household applications.

Contrary to the solutions known from the art there is no need of a completely new household appliance and equivalent additional storage space. Rather, the attachment adds a further useful component to the already existing attachments such as mixers, blenders, etc. This is a particularly space-saving solution and far cheaper than an additional electric appliance with its own drive.

Furthermore, the attachment of the invention is easy and safe to use in the domestic field. The invention represents a simple and economical solution because the two shaft ends are joined P:\WPDOCS\CAB\SPECI\7817703.doc-27/01/05 -2atogether by positive engagement by simply plugging together the shaft couplings. In this arrangement the shaft couplings can be constructed as spur-toothed gears.

C, An advantageous embodiment of the present invention is provided by the features of patent claim O 5 2. This type of vacuum pump features in particular a higher suction power compared to the vacuum pumps used to date for domestic applications. This means furthermore that the overall height can be small because there is no need of any elaborate rod mechanisms and gears. The vacuum pump can be directly driven with the rotational frequency of the drive shaft of the household appliance.

This also reduces the number of components, which has a positive effect in turn on the costs of manufacture. Finally, it takes just a few seconds with such a vane-type pump to generate the required level of pressure in a food container.

WO 02/46044 Al PCT/EP01/13147 06499 A further advantageous embodiment of the present invention is provided by the features of patent claim 3. In this arrangement the sealing lip is formed by a circumferential edge of elastomer plastic material projecting at the suction side. The cross section of the sealing lip may widen toward the free end. This makes it easier for the attachment to be mounted on a suitable valve of a storage container for food. Locating it centrally relative to a corresponding valve opening, as is required with devices of the art, is thus eliminated. The sealing lip works in this case like a suction cup.

Yet another advantageous embodiment of the present invention is provided by the features of patent claim 4. The result is a simple and low-cost plug-type connection with a handheld household appliance such as an immersion blender. This plug-type connection is very sturdy and at the same time may serve as a centering arrangement for connecting the shaft couplings.

Finally, a further advantageous embodiment of the invention is provided by the features of patent claim 5. An additional safety function is thereby provided to prevent liquid from entering the pump chamber during the evacuation operation. The solution is simple and low-cost.

For example, it is possible to provide a simple spherical float in a riser, which floats on the liquid surface and closes a valve opening when the liquid has reached a predetermined level.

An advantageous further aspect is also provided by the features of patent claim 6.

Thereby the vacuum pump of the attachment is rendered temperature-resistant in its operating range. A self-lubricating effect is also achieved thereby. Consequently the vacuum pump displays low pressure losses and requires no maintenance.

Yet another advantageous further aspect is provided by the features of patent claim 7.

Temperature resistance within the operating range is thereby assured as before. In addition to this, however, the occurring centrifugal forces are withstood without any deformations of unacceptable magnitude. This is also promoted by the material-related light-weight construction.

Another advantageous further aspect is provided by the features of patent claim 8. In this arrangement, the lamellae configured, for example, as rectangular plates may either be freely movable, actuated solely by centrifugal force, or be exposed to spring pressure. By suitable material selection a self-lubricating, maintenance-free construction is made available.

Finally, an advantageous further embodiment of the attachment of the invention is provided by the features of patent claim 9. This choice of material represents a cheap hygienic WO 02/46044 Al PCT/EP01/13147 06499 construction that enables a multiplicity of designs. Some of the possible materials are, for example, polyethylene, polypropylene, polyamide or any other thermoplastic material.

Further aspects and advantages of the present invention will be explained in the subsequent description of embodiments with reference to the accompanying drawings. In the drawings, FIG. 1 is a schematic sectional view of a first embodiment of an invention device for evacuating a storage container for food; FIG. 2 is a perspective exploded view of the device of FIG. 1; FIG. 3 is a perspective detail view of the vane-type pump forming part of the device of FIG. 1; FIG. 4 is a perspective view of an immersion blender with an attachment according to the embodiment of FIG. 1; FIG. 5 is a schematic sectional view of a second embodiment of an invention device for evacuating a storage container for food with a float section; and FIG. 6 is a graph showing, by way of comparison, the evacuation time for a 700 ml container of an attachment of the invention and the evacuation time for conventional vacuum pumps for household use.

Identical or similar components will be identified in the following with the same reference characters.

FIG. 1 shows a schematic sectional view of an advantageous embodiment of an attachment 1 in accordance with the present invention. The attachment 1 has a coupling section 2, a pump section 3 and a suction section 4.

The coupling section is formed by a cup-shaped plug-in shank 6 and a coupling gear 7 arranged within. The plug-in shank has in its base area a base opening 9 through which a shaft 8 connected with the coupling gear 7 is passed.

The vacuum pump arranged in the pump section 3 is constructed as a vane-type pump 17, as shown in the perspective detail view of FIG. 3. The pump housing of the vane-type pump 17 is formed by a graphite ring 16 which is covered at its upper and lower end by a circular WO 02/46044 Al PCT/EP01/13147 5 06499 upper end disk 18 and a lower end disk 12, respectively. A cylindrical rotor 10 is eccentrically mounted for rotation in the pump housing. The rotor 10 has an arrangement of uniformly distributed radial grooves 32. Accommodated in the grooves 32 are radially displaceable lamellae 11. The lamellae 11 are pressed against the graphite ring 16 by centrifugal force, supported in the present embodiment by the force of springs 26. This results in the formation of fluid-delivery cells 22 which become wider and narrower in a crescent-shaped configuration.

As becomes apparent from FIG. 1, the rotor 10 is connected to a shaft 8 which at the one end is passed through the end disk. The end of the shaft 8 projecting out of the upper end disk 18 has a coupling gear 7 constructed as a spur-toothed gear. Furthermore, in coupling section 2 provision is made for an annular sheath which continues along the wall of the housing This shaft-side housing end of the attachment 1, which is constructed as a plug-in shank 6, is intended for connecting to the tool-side end of an immersion blender.

Formed at the other end of the housing 5 around the outer circumference is a circumferential sealing lip 13 made of an elastic rubber material, which is connected via a groove 15 to a bar 14. The sealing lip 13 is constructed to act as a kind of suction cup when in operation. The cover 33 fitted to this end of the housing 5 has suitable suction slots 28. The suction slots 28 lie within the section of the cover 33 surrounded by the annular sealing lip 13.

FIG. 2 is a schematic exploded view of the embodiment of FIG. 1. It shows the plug-in shank 6 of essentially cup-shaped configuration in coupling section 2 and the coupling gear 7 arranged at its bottom. Also shown schematically in the pump section 3 are the rotor 10 and the shaft 8 which connects the coupling gear 7 to the rotor 10. The rotor 10 is received by the graphite ring 16 which is arranged in turn in the housing 5. Finally, the suction port 4 with the sealing lip 13 made of elastomer plastic is shown at the lower end of the elongated cylindrical housing FIG. 3 shows schematically a perspective detail view of the vane-type pump 17 of FIG.

1. Visible is the opened upper end disk 18, which is made of graphite like the cylindrical graphite ring 16 and the lower end disk 12. Provided eccentrically to the center of the circular upper end disk 18 is a bore which acts as the shaft bearing 20 of the rotor shaft 8, not shown. The shaft bearing 20 is constructed as a self-lubricating plain bearing. The rotor 10 carried by the shaft 8 is arranged within the cylindrical graphite ring 16 which together with the upper end disk 18 and the lower end disk 12 forms the pump housing of the vane-type pump 17.

WO 02/46044 Al PCT/EP01/13147 06499 The carbon-fiber rotor 10 is arranged eccentrically to the center of the graphite ring 16.

It has three grooves 32 arranged at an angular offset of 1200 to each other, in which lamellae 11 are guided such as to be longitudinally displaceable in radial direction. The lamellae 11 are fabricated essentially as rectangular graphite plates. At their end facing the shaft bore 21 of the rotor 10 the lamellae 11 are acted upon by the pressure of compression springs 26. Also visible is the suction opening 19 arranged on the lower end disk 12, through which air is drawn out of a storage container. The fluid-delivery cells 22 are formed by the rotor 10, the upper end disk 18, the lower end disk 12, the graphite ring 16 and the lamellae 11.

With the vane-type pump 17 in operation, the rotor turns with the shaft speed of the immersion blender 23. As the result of the centrifugal force and the spring force the lamellae 11 slide along the inner wall of the graphite ring, hence guaranteeing that no pressure compensation takes place between the various fluid-delivery cells.

FIG. 4 shows a perspective view of an attachment 1 of the invention, which is mounted on the output end of an immersion blender 23. The essentially elongated cylindrical equipment combination has at its upper end a grip 24 which can be gripped all-round by the user's hand.

On the front side of the immersion blender 23 in the upper region is an actuating switch which is easy to operate with the gripping hand.

In this arrangement the upper region of the housing 5 of the attachment 1, which is constructed as a plug-in shank 6, is pushed over the slightly conical output end of the immersion blender 23. As this occurs, the shaft connection for driving the vacuum pump is established simultaneously.

A circumferential sealing lip 13 made of elastomer plastic is arranged on the lower end of the attachment 1. The smooth outer walls of the immersion blender 23 and the attachment 1, which are made of thermoplastic material, make it easy to clean the equipment combination, which is important for household appliances in particular for reasons of hygiene.

The attachment 1 is connected during operation to the output end of the immersion blender 23. The attachment 1 is held by the annular sheath at the output end of the immersion blender 23 such that it cannot tilt or twist. The output shaft of the immersion blender 23 is in positive engagement with the coupling gear 7 of the vane-type pump 17. The suction side of the attachment 1 sits on a valve device which is arranged on a storage container for food. The circumferential sealing lip 13 sucks itself tight against a smooth circumferential edge of a WO 02/46044 Al PCT/EP01/13147 06499 connecting arrangement of the valve device. While the storage container is being evacuated the rotor 10 of the attachment 1 is set in rotation by the drive shaft of the immersion blender 23.

FIG. 5 shows a second embodiment of the present invention in which added provision is made for a float section 29. This prevents liquid from entering the vane-type pump 17. In this embodiment the constructional configuration of the coupling section 2 and the pump section 3 is essentially the same as the configuration described with reference to FIGS. 1 to 4.

In this embodiment a float section 29 adjoins the pump section 3. The float section 29 is essentially formed by a cylindrical float housing 31 made of thermoplastic material. At its lower end the float housing 31 has a bar 14 which engages in a groove 15 of a sealing lip 13 forming the suction port 4.

A spherical float 30 is provided in the float housing 21. The float 30 is constructed as a hollow body so that it easily floats on inflowing liquid. When the level of liquid in the float housing 30 reaches a critical value, the lower opening of the suction pipe 27 is closed by the float No liquid then gets into the vane-type pump 17. Additional suction slots 28 are provided at the lower end of the float housing 31 in order to guarantee with certainty that the air existing in a storage container for food is evacuated.

FIG. 6 shows a graph in which the evacuation time for a 700 ml container is presented.

The time t in seconds is plotted on the x-axis and the pressure in mbar on the y-axis. At the time t 0 the pressure inside the container equals the ambient pressure. When the vacuum pump is activated, the pressure inside the container is reduced. The development of pressure j as a function of time can be represented as a logarithmic function. Only when using the embodiment of the invention does it take just 5 seconds to attain a container pressure of around 300 mbar, whereas comparable units attained only pressures of about 500 to 700 mbar during this time period. After just 15 seconds with the attachment of the invention the pressure attained is 200 mbar and does not drop thereafter by any appreciable amount. By contrast, the comparable units attained only a pressure of around 300 to 400 mbar in the same period of time. This underlines the evacuating power and speed of the attachment of the invention.

P:\WPDOCS\CAB\SPECI\7817703.doc-3006/04 -7A- The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that the prior art forms part of the common general knowledge in Australia.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference numerals in the following claims do not in any way limit the scope of the respective claims.

Claims (9)

1. An attachment device for a handheld electric appliance, in particular an tt immersion blender or hand mixer having a drive shaft the attachment device being for evacuating a food storage container closable by a valve, the device including a vane type CI vacuum pump adapted to be driven by a rotary motion, a shaft coupling directly Sconnectable to the drive shaft of the household appliance and adapted to actuate the ,I vacuum pump so that the vacuum pump can be driven with the rotational frequency of the drive shaft.

2. The device according to claim 1, characterized in that said vane type vacuum pump (17) includes a rotor (10) having formed on it lamellae (11) that are movable outwardly against the inner wall of a graphite ring (16).

3. The device according to claim 1 or 2, characterized in that said attachment includes on its suction side a circumferential sealing lip (13) for seating engagement with a connecting arrangement.

4. The device accordingly to any one of the preceding claims, characterized in that said attachment includes as its input end a plug-in shank adapted to be slid onto the conical output end of a handheld electric household appliance.

The device according to any one of the preceding claims, characterized in that provision is made for a float section (29) between the vacuum pump (17) and the sealing lip (13) to prevent the entry of liquid into the vacuum pump (17).

6. The device according to patent claim 2, characterized in that the housing of the vacuum pump (17) is formed of a graphite ring and an upper end disk (18) and a lower end disk (12).

7. The device according to patent claim 2, characterized in that the rotor PA\PDOSARMSPEC78773_Br=,,_dlimsdoc27/01/05 -9- of the vacuum pump (17) is made of graphite fibers. oO

8. The device according to patent claim 2, characterized in that the lamallae Vt (11) of the vacuum pump (17) are made of graphite. Ni

9. The device according to any one of the preceding claims, characterized in Sthat the housing of the attachment is made of a suitable thermoplastic material. A device for evacuating a food container substantially as hereinbefore described with reference to the accompanying drawings. DATED this 2 7 th January, 2005 BRAUN GmbH By Its Patent Attorneys DAVIES COLLISON CAVE