GB2057406A - Combined cleaning and extraction head for tanks for liquid products - Google Patents

Abstract

A downwardly extending pipe through which a liquid product, such as beer, is extracted from a tank and through which a cleaning fluid is discharged into the tank carries a head 2 with apertures 28 through which the product is extracted, and a valve member 26 for closing the apertures 28 during the supply of cleaning fluid through a duct 17 to a cleaning assembly 4. <IMAGE>

Description

SPECIFICATION Improvements in the extraction of liquid products from tanks containing the same, and the supply of cleaning fluid to such tanks This specification is concerned in general with tanks used for the processing or storage of liquids, and is more especially concerned with arrangements for extracting the contents of such tanks and supplying thereto cleaning fluids.

In various industries, it is usual for liquid products to be treated within a storage tank.

Often, for reasons of convenience and speed, the product is withdrawn from the tank and subjected to a continuous phase of the process, such as cooling or blending with additives, before returning the liquid to the tanks. An example is to be found in those breweries wherein, following fermentation, the beer is withdrawn from the tank and passed through a circuit which incorporates a heat exchanger for abruptly cooling the beer in order to terminate the fermentation stage.

Advantageously, in order to ensure that the hottest liquid is treated first, the beer is extracted by way of a suction pipe immersed in the surface of the liquid, and the cooled liquid is reintroduced into the lower part of the vessel. After the batch has been completely processed and finally discharged from the tank, it is usual to clean the tank by spraying into it a cleaning fluid consisting of a diluted detergent. Preferably, the pipe work associated with the tank and through which the beer is circulated is also cleaned.

The conventional tank, therefore, incorporates two separate and distinct networks of piping, one for the extraction and reintroduction of the beer and the other with associated diffusion bells for the supply of cleaning fluid, with the result that there are numerous connections and branches extending at right angles to the tank. Valves for safeguarding and isolating the control members and multiple links are thereby rendered necessary, so resulting in high manufacturing and installation costs.

In order to dispense with this double network and numerous branches, the present invention provides for a pipe to extend downwards within the tank and bear at its lower end an extraction head connected with a cleaning device, the suction head including a valve, and the pipe being connected to the exterior of the tank by a single circuit having a return branch, by way of a restricted number of valves.The extraction head may comprise a casing having a peripheral wall with a cylindrical portion surmounted by a generally tapering portion, a removable unit secured within the base of the casing and comprising a tube with an integral apertured lower collar, the tube including downwardly and upwardly projecting portions, the downwardly projecting portion being connected to a cleaning device, the upwardly projecting portion opening within the casing and being centred by an apertured upper collar integral with the casing, and a valve member within the casing for closing the apertures in the lower collar. The head forms a very reliable and simple mechanical assembly which may be cleaned externally by suitably placed orifices for the discharge of cleaning fluid.

The interior of the head is preferably designed so that the cross-sectional area of the passage for the extracted product therethrough is at least equal to that of the pipe to avoid significant variations in flow rates which would cause throttling of the liquid and imparing of the products in the case of beverages.

By virtue of the invention, the cleaning assembly of the conventional tank, together with its numerous branches at right angles to the tank and the various bells are dispensed with. The separate extraction network is similarly eliminated, and the two networks replaced by the common pipe for the extraction of the liquid product and introduction of cleaning fluid.

The invention will now be described in greater detail but by way of example only with reference to the accompanying drawings, wherein: Figure 1 is a schematic view showing a tank for a liquid product and the circuits associated therewith, Figure 2 shows to a larger scale the extraction head and cleaning assembly of the tank shown in Figure 1 in part longitudinal section, Figure 3 is a section taken on the line Ill-Ill in Figure 4, Figure 4 is a plan view of a lower collar of the head shown in Figure 2, Figure 5 is a view taken on the line V-V in Figure 6, Figure 6 is a plan view of one half of the upper collar, and, Figure 7 is a view similar to Figure 2 showing an alternative embodiment with the valve depicted in its open position at the left hand side of the Figure and in its closed position at the right hand side of the figure.

Referring to Figure 1, the invention will be described in the context of a beer fermentation tank, in particular a large volume tank of the external type, although it will be appreciated that it has utility in other connections within the food industry and in other industries.

Arranged within the tank on the vertical axis thereof is a single downwardly extending pipe 1 for the extraction of liquid products from the tank and the introduction into the tanks of cleaning fluid. Mounted upon the lower end of the pipe is an extraction head 2 having at least one aperture through which the liquid product may be drawn into the pipe and a valve for closing the aperture or apertures during the supply of cleaning fluid to a cleaning device 3 mounted coaxially beneath the head 2. The pipe 1 may also be used to introduce or reintroduce the liquid product itself into the tank, provided that the flow rate and pressure thereof is such that the valve may remain open.

Externally of the tank is arranged a circuit 6 including a common product extraction and cleaning fluid supply line 10 and a cleaning fluid return line 11 both connected to a three-way valve 9 by way of which the lines 10 and 11 may be made to communicate with each other or the line 10 to communicate with the pipe 1 by way of shut-off valve 7. Between the valves 7 and 9, is a valve 8 by way of which the tank may be connected to atmosphere. The lines 10 and 11 connect with a treatment plant 12 including stations for cooling and centrifuging the liquid product and carrying out any other necessary treatment, as well as the supply and recovery of the cleaning fluid, the plant 12 being connected with the bottom of the tank by way of a line 13.

In operations, during an external processing stage, the valve 7 is opened and the valve 9 set to a position to connect the pipe 1 with the line 10.

The liquid product within the tank is drawn through the head 2, pipe 1 and line 10 to the plant 12, and returned to the tank through the line 13.

After processing has been completed and the liquid product discharged, the tank may be cleaned by setting the valves 7 and 9 in the positions mentioned above and passing cleaning fluid through the line 10 and pipe 1 to the cleaning device 3, and withdrawing the cleaning fluid through the line 13. Cleaning fluid may also be passed through the line 10 and returned by way of the line 11.

Referring now to Figures 2 and 6, it will first be noted that the cleaning device may include a rotary body 4 provided with rotors 5 whereby the cleaning fluid may be sprayed throughout the interior of the tank. The relative dimensions of the head 2 and the cleaning device are such that the plane in which the rotor or rotors rotate does not intersect the structure of the head 2. The rotary body 4 of the cleaning device is carried by a neck which is screwed onto the end of a lower portion of a tube 17 projecting from the head 2.

The head comprises a body or casing 14 having an outer wall with a cylindrical portion surmounted by a frusto-conically tapering portion terminating in a neck for attachment of the pipe 1.

The above-mentioned tube 17 forms with an integral collar 19 a removable unit screwed into a screw-threaded ring at the lower end of the outer wall and held against rotation by pins 20.

The upper portion of the tube 17 above the lower collar 19 extends upwardly to a point within the tapering portion of the body, and is centred by a collar 22 integral with the body and having a central opening engaging a shoulder 23 adjacent the upper end of the tube 17. A chamber 15 is defined between the two collars and houses a valve member 26 of a non-return valve for controlling flow through apertures 28 in the lower collar. The valve permits the flow of the liquid product into the chamber 15 during the extraction stage, the product passing into the pipe by way of apertures 28 in the upper collar 22.

The valve member is generally toroidal in shape and surrounds the upper portion of the tube, being guided thereby for vertical movement between its lower closed position and its upper open position.

The valve member has a convexly curved lower surface which merges into cylindrical inner and outer peripheral surfaces, the former of which is guided on the tube. The upper surface of the valve member is formed by an inclined frusto-conical surface portion 30 terminating in a horizontal edge 29. During the extraction phase, upper limiting position is determined by contact of the edge 29 with the inner rim 25 of the collar 22 while the inclined portion 30 ensures an adequate flow passage from the apertures 28 to the apertures 24, so preventing the creation of differing rates of flow through the head which might impare the product.

The arrangement of the apertures 28 which are closed by the valve member is best shown in Figure 3, from which it can be seen that these apertures are formed at the bottom of a circumferentially extending trough or recess into which the convexly curved undersurface 27 of the valve member may engage to produce a satisfactory sealing action by contact with the upper edges of the trough forming the valve seat.

As best shown in Figure 4, each of the apertures is of elongated form and is separated from the others by a narrow spoke-like or radiating web spaced from the upper surface of the collar.

During the cleaning phase, cleaning fluid supplied under pressure to the pipe 1 passes into the interior of the head and through the tube 17 to the cleaning arrangement. The pressure of cleaning fluid within the head forces the valve member onto its seat. Transversely extending grooves 31 are formed in the edges of the seat and permit jets of cleaning fluid to bypass the valve to clean adjacent zones of the head and to prevent the formation of an idle zone in the chamber 15 during the cleaning operation. Jets of fluid may similarly pass through calibrated orifices 32 in the conical portion of the body to clean the exterior of the pipe 1, and through the calibrated orifices 21 to clean the underside of the head.Jets passed through the orifices 32 assist in removing deposits which may accumulate at the surface level of the liquid, which may consist of a ring of bitters in the case of a beer fermentation tank.

To avoid imparing the product by causing the liquid products to flow through the head at an excessive local speed, the surfaces and the number of apertures 24 and 28 are so arranged that the total free cross-sectional area of the passageway through each collar is at least equal to the cross-sectional area of the pipe 1.

In certain processes, it is important to be able to introduce liquid into the upper part of the tank, this being the case in particular when a centrifuging operation is carried out at a lower rate of flow at the end of the beer fermentation phase.

For this purpose, the valve may be provided with means to prevent its closure below a critical determined flow rate and pressure, or to ensure a progressive closure. Thus, in the embodiment shown in Figure 7, a compression spring 35 surrounding the tube 17 7 is arranged between the valve and its seat, the spring being received within an annular recess 34 in the valve member. The spring ensures that the valve is held open during the relatively low flow rates at which the product enters the tank through the pipe 1 but allows the valve to close when cleaning fluid is introduced at a substantially higher pressure.

Claims (16)

1. In a tank used for the processing or storage of liquid products, an arrangement for the extraction of a liquid product from the tank and the discharge into the tank of cleaning fluid, said arrangement comprising a pipe extending downwardly within the tank and bearing at its lower end an extraction head connected with a cleaning device, the extraction head including a valve, and the pipe being connected to the exterior of the tank by a single circuit having a return branch, by way of a restricted number of valves.

2. A tank for the processing or storage of liquid products, having therein a downwardly extending pipe by way of which the contents of the tank may be extracted and through which cleaning fluid may be supplied, said pipe being provided with an extraction head and a cleaning device at its lower end, the extraction head having at least one aperture through which the contents of the tank may be drawn during the evacuation of the tank, and a valve for closing the opening or openings during the supply of cleaning fluid through the pipe to the cleaning device.

3. The invention claimed in claim 1 or claim 2, wherein the extraction head comprises a casing connected to the pipe and having a lower wall from which a tube extends to the cleaning device, the lower wall being formed with said apertures.

4. The invention claimed in claim 3, wherein the lower wall is formed by a collar integral with the tube, the collar being secured removably in the housing, said tube including a portion extending upwardly into the housing and being centred by an apertured collar integral with a peripheral wall of the casing.

5. The invention claimed in claim 4, wherein the peripheral wall of the casing includes a cylindrical portion surmounted by a generally frusto-conical portion.

6. An extraction and head cleaning assembly for a tank for liquids, said head comprising a casing having a peripheral wall with a cylindrical portion surmounted by a generally tapering portion, a removable unit secured within the base of the casing and comprising a tube with an integral apertured lower collar, the tube including downwardly and upwardly projecting portions, the downwardly projecting portion being connected to a cleaning device, the upwardly extending portion opening within the casing and being centred by an apertured upper collar integral with the casing, and a valve member within the casing for closing the apertures in the lower collar.

7. The invention claimed in any of claims 4 to 6, wherein the apertures in each collar are uniformly distributed about its axis.

8. The invention claimed in any of claims 4 to 7, wherein the apertures in the lower collar are elongate and formed between radial webs recessed relative to the plane of the upper surface of the collar.

9. The invention claimed in any of claims 4 to 8, wherein the total cross-sectional area of the apertures in each collar is at least equal to the cross-sectional area of the pipe.

10. The invention claimed in any of claims 4 to 8 wherein the valve member is annular.

11. The invention claimed in claim 10, wherein the valve member surrounds the upper portion of the tube and is guided thereby for vertical movement, the member being generally toroidal in shape with a rounded lower face and vertically extending inner and outer side surfaces.

12. The invention claimed in claim 1 wherein the valve member has an upper surface which rises from the outer edge of the valve member towards its centre, frusto-conically or otherwise, and terminating in an annular edge for contact with the upper collar.

13. The invention claimed in any of claims 10 to 12, wherein the lower collar has a circumferentially extending recess, in the bottom of which are formed the apertures of that collar, the upper edges of the recess forming the valve seat.

14. The invention claimed in any of claims 10 to 13, including resilient means associated with the valve member or its seat to render closure of the valve progressive or such as to take effect at a predetermined critical flow rate and pressure.

15. The invention claimed in any of claims 10 to 14, including a spring surrounding the upper tube portion and engaging in an annular recess in the valve member for biasing the valve member to its open position.

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16.The invention claimed in any of claims 4 to 1 5, including orifices in the casing and lower tube portion for the discharge of jets of cleaning fluid.