GB2071693A

GB2071693A - Discharging granular materials

Info

Publication number: GB2071693A
Application number: GB8018965A
Authority: GB
Original assignee: Briggs & Co Ltd S
Current assignee: Briggs & Co Ltd S
Priority date: 1979-07-02
Filing date: 1980-06-10
Publication date: 1981-09-23
Also published as: GB2071693B

Abstract

In apparatus such as a mash tun for a brewery, discharge of spent granular or like material, which has been treated with a liquid, is effected by a rotary paddle mounted on a circular section shaft whereof the blades have a low profile and sweep closely over a strainer forming the bottom of the treatment space of the apparatus. <IMAGE>

Description

SPECIFICATION Discharging granular materials The invention relates to apparatus with means for discharging granular and other divided materials from a vessel in which a bed of the material has been treated with liquid.

It is part of the process in brewing beers and the like to treat a bed of grain with hot water to produce wort. The liquid percolates through a substantial depth of grain which is above a strainer plate positioned in a mash tun slightly above the tun bottom, the wort draining from the grain bed into a space below the strainer plate. At intervals the spent grain bed is removed through a bottom outlet.

The presently used equipment for removing the spent grain comprises a rotary paddle for sweeping the grain over the outlet which is offset from the paddle shaft. The paddle is carried by an hydraulic jack so that the paddle can be gradually lowered during grain removal and so that the paddle always acts on the top layer of grain.

It has long been known that the arrangement has disadvantages arising from the fact that both the driving motor and gearing for the paddle and the hydraulic jack are below the mash tun, the paddle shaft usually being square to allow for its lengthwise movement in raising and lowering the paddle. The square shaft necessitates the provision of a rotating gland as a seal in the bottom of the mash tun and with this form of gland it is difficult to avoid leakage of liquid past the gland. As a result, the mash tun contents may be contaminated by hydraulic fluid, or the hydraulic fluid by wort.

The invention provides apparatus, such as a mash tun, for treatment of a granular or other divided material with a liquid comprising a vessel having a strainer plate separating a treatment space from a liquid drainage space, and a paddle mounted for rotation on a circular-section shaft and having paddle blades with a low profile as viewed in the direction of rotation which blades in rotation sweep closely over the strainer plate.

It is found that with this arrangement, the need for an hydraulic jack with a square or axiallymovable shaft for the paddle is eliminated, and thus the seal when the shaft passes through the bottom of the mash tun is a circular seal.

It is found that when the apparatus is a mash tun, although the paddle of the invented arrangement always operates during grain discharge with the remaining head of grain above it and although the paddle has a low profile, efficient discharge of the spent grain is obtained.

Further this may be achieved even though the speed of rotation of the paddle is substantially reduced as compared with that of the presentlyused paddle.

One construction of grain discharge means of the invention applied in a mash tun is illustrated in the accompanying drawings in which: Fig. 1 is an elevation, partly in section, of the mash tun fitted with the discharge means, and Fig. 2 is a diagrammatic plan view.

The mash tun 10 is supported on pillars 11 and has near its bottom a standard form of strainer plate 12 separating the wort collecting space 13 from the grain bed which in operation is above the plate 12. A grain discharge outlet 14 is provided offset from the centre of the tun. The outlet will be controlled by a suitable valve (not shown).

The grain discharge means of this embodiment comprises a paddle with a pair of blades 1 5 extending diametrically from the central boss 1 6 which is carried on a vertical, circular-section shaft 17. The shaft 1 7 extends both upwards to project from the tun and downwards through the tun bottom to a drive unit comprising an electric motor 18 and gearing in a gear casing 19. This arrangement allows simplified sealing where the shaft extends through the tun bottom.

The blades 1 5 are arranged closely above the plate 12, are cranked as seen in plan to sweep grain towards the outlet 14 and, because of their length, are connected by stays 20 to the top of the shaft 17 to prevent undue flexing and consequent damage to the plate 12.

It will be seen also that the blades 1 5 present a low profile when viewed in the direction of paddle rotation as indicated by arrow 21 so that they pass easily through the grain bed even at commencement of the discharge operation.

Nevertheless a good rate of grain discharge can be achieved even with a relatively slow rate of paddle rotation. A suitable form of blade has a rectangular cross-section and has an aspect ratio of 1:6 being for example +" thick and 3" wide. A blade clearance from the strainer plate 1 2 of say +" is convenient.

To assist in discharging the grain a deflector 22 may, as shown, be provided on the tun wall just above the level of the blades 1 5.

It sometimes occurs that material from the grain bed, which essentially should be floating in the treatment liquid, falls to the bottom of the treatment space so clogging the strainer plate and preventing wort drainage. It is found that rotation of the paddle can create sufficient disturbance adjacent the strainer plate as to prevent or clear clogging.

1. An apparatus, such as a mash tun, for treatment of a granular or other divided material with a liquid which apparatus comprises a vessel with a strainer plate separating a treatment space from a liquid drainage space and with a discharge outlet for the material, and a paddle mounted for rotation on a circular-section shaft and having paddle blades with a low profile as viewed in the direction of rotation, which blades in rotation sweep closely over the strainer plate.

2. Apparatus according to claim 1 wherein the shaft extends both upwards to project from the vessel and downwards through the vessel bottom to a drive unit, there being stays from the upper shaft end to support the outer portions of the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Discharging granular materials The invention relates to apparatus with means for discharging granular and other divided materials from a vessel in which a bed of the material has been treated with liquid. It is part of the process in brewing beers and the like to treat a bed of grain with hot water to produce wort. The liquid percolates through a substantial depth of grain which is above a strainer plate positioned in a mash tun slightly above the tun bottom, the wort draining from the grain bed into a space below the strainer plate. At intervals the spent grain bed is removed through a bottom outlet. The presently used equipment for removing the spent grain comprises a rotary paddle for sweeping the grain over the outlet which is offset from the paddle shaft. The paddle is carried by an hydraulic jack so that the paddle can be gradually lowered during grain removal and so that the paddle always acts on the top layer of grain. It has long been known that the arrangement has disadvantages arising from the fact that both the driving motor and gearing for the paddle and the hydraulic jack are below the mash tun, the paddle shaft usually being square to allow for its lengthwise movement in raising and lowering the paddle. The square shaft necessitates the provision of a rotating gland as a seal in the bottom of the mash tun and with this form of gland it is difficult to avoid leakage of liquid past the gland. As a result, the mash tun contents may be contaminated by hydraulic fluid, or the hydraulic fluid by wort. The invention provides apparatus, such as a mash tun, for treatment of a granular or other divided material with a liquid comprising a vessel having a strainer plate separating a treatment space from a liquid drainage space, and a paddle mounted for rotation on a circular-section shaft and having paddle blades with a low profile as viewed in the direction of rotation which blades in rotation sweep closely over the strainer plate. It is found that with this arrangement, the need for an hydraulic jack with a square or axiallymovable shaft for the paddle is eliminated, and thus the seal when the shaft passes through the bottom of the mash tun is a circular seal. It is found that when the apparatus is a mash tun, although the paddle of the invented arrangement always operates during grain discharge with the remaining head of grain above it and although the paddle has a low profile, efficient discharge of the spent grain is obtained. Further this may be achieved even though the speed of rotation of the paddle is substantially reduced as compared with that of the presentlyused paddle. One construction of grain discharge means of the invention applied in a mash tun is illustrated in the accompanying drawings in which: Fig. 1 is an elevation, partly in section, of the mash tun fitted with the discharge means, and Fig. 2 is a diagrammatic plan view. The mash tun 10 is supported on pillars 11 and has near its bottom a standard form of strainer plate 12 separating the wort collecting space 13 from the grain bed which in operation is above the plate 12. A grain discharge outlet 14 is provided offset from the centre of the tun. The outlet will be controlled by a suitable valve (not shown). The grain discharge means of this embodiment comprises a paddle with a pair of blades 1 5 extending diametrically from the central boss 1 6 which is carried on a vertical, circular-section shaft 17. The shaft 1 7 extends both upwards to project from the tun and downwards through the tun bottom to a drive unit comprising an electric motor 18 and gearing in a gear casing 19. This arrangement allows simplified sealing where the shaft extends through the tun bottom. The blades 1 5 are arranged closely above the plate 12, are cranked as seen in plan to sweep grain towards the outlet 14 and, because of their length, are connected by stays 20 to the top of the shaft 17 to prevent undue flexing and consequent damage to the plate 12. It will be seen also that the blades 1 5 present a low profile when viewed in the direction of paddle rotation as indicated by arrow 21 so that they pass easily through the grain bed even at commencement of the discharge operation. Nevertheless a good rate of grain discharge can be achieved even with a relatively slow rate of paddle rotation. A suitable form of blade has a rectangular cross-section and has an aspect ratio of 1:6 being for example +" thick and 3" wide. A blade clearance from the strainer plate 1 2 of say +" is convenient. To assist in discharging the grain a deflector 22 may, as shown, be provided on the tun wall just above the level of the blades 1 5. It sometimes occurs that material from the grain bed, which essentially should be floating in the treatment liquid, falls to the bottom of the treatment space so clogging the strainer plate and preventing wort drainage. It is found that rotation of the paddle can create sufficient disturbance adjacent the strainer plate as to prevent or clear clogging. CLAIMS

2. Apparatus according to claim 1 wherein the shaft extends both upwards to project from the vessel and downwards through the vessel bottom to a drive unit, there being stays from the upper shaft end to support the outer portions of the blades.

3. Apparatus according to claim 1 or claim 2 wherein the blades are cranked as seen in plan to sweep material towards the outlet.

4. A mash tun or the like with a grain discharge arrangement substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.