IE20030623U1 - Improvements in and relating to the kilning of barley - Google Patents

Abstract

ABSTRACT The present invention relates to a kilning process for germinated barley using a vertical kiln (1). The vertical kiln is so arranged that there is a pre—treatment zone (5) which allows very wet barley, at initial intake, usually with a moisture content of the order of 43%, to be dried somewhat so as to provide a more cohesive and easily controlled product for further drying and kilning. The operation is carried out by the introduction of hot air and the recirculation and extraction of hot air.

Description

Introduction The present invention relates to a continuous kilning process for germinated barley using a vertical kiln having vertically spaced—apart inlets and outlets for the control of detemperatweddregmmfiierehflwanarigenzemofmemletsaridmruetsbeing such as to allow the provision of heat treatment zones within the kiln. Such germinated bariey is often called green malt and the term is used interchangeably in this specification.

Following germination of bartey, krining vessels are used to complete the mafing process using indirect heating equipment.

In the past, kilning vessels were usually vertically arranged vessels of this type where the grain was introduced at the top of the kiln and then subsequently delivered out the bottom of the kiln, the germinated grain being transferred downwards through a number of zones, usually a pre-treatment zone, an upper intermediate zone, a lower intemiediate zone and then a final zone where the final kilning operation was carried out and the grain was discharged. Because of the relative inefficiencies of air flow and _ the difficulty in controliing the quaiity of malt produced, another solution was proposed.

This has been found to be very successful in producing good malted barley.

However, there are a large number of vertical kilns still in use, representing a considerable investment but, however, are not efficient in use and do not produce consistently high quality green malt.

A typical example of such a vertical kiln is described in US Patent Specification No. 3205152 (Geys). This particular vertical kiln is directed to overcoming the problem of unequalandhaphazardkikfingbyprwiditganumberofsetsofbarsdisposed it vertically throughout the kiln, which bars can be agitated to cause the grain to be delivered from one part of the kiln to the next. However, this is a relatively elaborate construction and is quite difficult to control in use.

Nouoadsul onancfiu N3_d0 The present invention is directed towards overcoming the problems inherent in the operation"of a vertical kiln.

Statements of invention‘ According to theinvention, there is provided_ a continuous kiining process for germinated barley using a vertical kiln having vertlcaily spaced-apart air inlets and _ outlets forthe control of the temperature of the grain therein, the arrangement of the inlets and outletsbeing such as to allow the provision of heat treatment zones within the kiln, namely, an enlarged upperipre-heatrtreatment zone ‘forming a. grain inlet and four descending heat treatment zones, I namely, an initial heat treatment zone, an upper intermediate heat treatment zone, a lower intermediate heat treatment zone and a lowermost final heat treatment zone above a discharge outlet, the method comprising -controlling the temperature of the air within the kiln and the quantities of air introduced and removed from the kiln, whereby a predetermined rate of discharge of. the grain at a desired moisture content is achieved, the method comprising:- ‘ ‘I continuously adding the grain to the top of the kiln over a larger area than that of the rest of the kiln to ensure that most of the very moist grain is close to the top of the kiln; delivering a main supply of pressurised hot air into the kiln at the final treatment zone in contraflow with the grain’ to agitate and mix the grain [as it falls through the kiln; removing air from the kiln for drying and controlling the air temperature as it travels up the kiln and adding to or removing air from the kiln such that the air in the pre-treatment zone is between 20°C and 45°C; reducing the moisture content of the grain rapidly on introduction of the grain into the kiln to ensure that the grain, on discharge into the initial heat treatment zone, has a moisture content of between 33% and 37%; maintaining the air temperature in the initial heat treatment zone at between 50 and 60°C and the grain moisture content at between 23% and 30% on discharge; maintaining the air temperature in the upper intermediate zone at between 65 and 73°C to ensure a grain moisture content of between 10%, and 14% on discharge; ' maintaining the air temperature in the tower intermediate zone at between 68 and 75°C and_the grain moisture content at between 5% and 8% on discharge; introducing air at between 75°C and 90°C into the final heat treatrnentzone to ensure a grain moisture content of between 4 and 5% on discharge; and continuously removing grain (25) from the kiln. it has been found that by the use of what is effectively a greatly enlarged upper pre- heat treatment zone forming a grain inlet and the subsequent treatment of the grain initially therein; rather than just lettingthe barley rest there, it has provedxvery ' advantageous in that the subsequent operations carried out on the germinated grain have been much more easily controllable and further, have allowed for a higher quality of malted barley to be prpdumd. Thevery moist barley is quickly partially dried so that it does not form lumps or channels for the discharge of the air. .

Further, the particular arrangement of not always adding heat but, in certain cases, moving heated air around the vessel, has allowed for greater control and also more "efficient kilning because operationally now, the kiln behaves more conventionally with similar improved process control to modern batch-type kiln vessels while, at the same time, having the added advantage of a continuous process. Thus, the present invention, by whatappears to be relatively minor improvements in the process, has resulted in a process that is considerable more efficient than heretofore, producing a much higher quality malted barley and, more importantly, has a considerably. greater throughput because the initial pre-treatment allows for the much more rapid kilning of the green malt thereafter, without any loss in quality, essentially by reducing the moisture content considerably from the normal input moisture content of the order of 43%. indeed, generally in thepre-heat treatment zone, somewhat of the order of over one quarter of the total moisture is removed, thus producing a much more easily handled and easily kilned product. ' A further-advantage is that the throughput of the kilns have been increased by over % by the use of the invention. ‘ Surprisingly, the reductionof moisture quickly, as the green malt is introduced into the kiln, has caused the whole operation of the kiln to work more efficiently with the air -being driven"up'th'e kiln in a manner such that it is more evenly distributed across the kiln and all the grain within the kiln appears to be agitated. and moved in an appropriate way. it is not fullyunderstood why this should be the case since one would have expected that by continuing to use side vents and the like, the agitation of the grain would have been better, than with the present invention. . in one embodiment of the invention, the air temperature in the pre~treatr_nent zone is of the order of 25°C and the discharge moisture content of the grain is of the order of %. in another embodiment of the invention, the air temperature and discharge moisture content is of the order of 55°C and 27%; 68°C~and 12%; 70°C and 6%; and 81°C and .5%; for the initial, upper intermediate, lower intermediate and final intermediate ' zones respectively, ideally, the air temperatures are so controlled as to ensure that the kilning process takes not less than 20 hours and not more than 24 hours. in accordance with the kilning process, on start-up and with the kiln empty, the steps are carried out of:- « 7 green malt is delivered into the kiln; air is delivered into the final zone and the grain treated as if in the pre- l treatment zone; ’ . when thegrain in the final heat treatment zone would be ready for transfer normally to the initial heat treatment zone, the batch in the final heat treatment zone is heated as if it were in the initial heat treatment zone and the batch in the lower intermediate zone is treated as if it were in the pretreatment zone; the process is repeated progressively upthe kiln until the grain in the final heat treatment zone is ready for discharge when the process is carried out as described above. I Detailed Description of the Invention The invehtion will be more clearlyunderstood from the following description of a ' process according to the invention, given by way of reference only ‘to the accompanying drawings, in which:- ’ Fig. 1 is a vertical part sectional schematic view of kiln according to the invention, and -Fig. 2 is a typical section along the lines ll-ll of Hg‘. 1.

Referring to the drawings, there is provided akiln, -indicated generally by the reference numeral 1, having exterior walls 2 tapering inwards at 3. Thehkiln l effectively provides a pre-heat treatment zone, an initial heat treatment zone, an upper ’ intermediate heat treatment zone, a lower intermediate heat treatment zone, and a final heat.-treatment zone, each identified generally by the reference numerals 5, 6, 7, 8 and 9 respectively. it will be appreciated that these heat treatment zones are not separated physically, but simply represent portions within the kiln. it will be noted that the pretreatment zone includes a relatively narrow portion below a greatly enlarged upper portion.

Mounted vwthin the kiln is an air duct 10 to which are connected a plurality of ducts 11, fans 12 and heaters 13. Each of the ducts terminates in a suitable outlet control valve . The arrangement of all the ducts is not shown in detail, nor indeed are all the |E030623, - IE0306?3 " inputs and-outlets for air. The ducts, except for the initial input of air into the kiln '1, all form part of a semi-closed loop system of heat exchanger and fan. Provision, not shown, to vent or introduce air into the system is provided and thus it is not, or more- properly, does not always operate in closed loop mode. The heat exchanger is used for heat recovery. The air may be returned to another fan for subsequent recirculation. A An input feed screw 20 is connected between a germination bed (not shown) and the kiln 1 for germinated barley delivery.

The various valves 15 and the ducts 11 are identified, as appropriate, by additional bracketed lower case letters for ease of understanding of the invention. -Mounted beneath the kiln 1 is a take-off conveyor 17 fed through outlet valves 18 in a discharge. outlet 19. in operation, with grain, identified by the reference numeral 25, is loaded intothe kiln 1 from the_ input feed screw 20. The grain 25 which is received, usually at about 43° moisture and ambient temperature is heated in excess of 20°C and less than 455C, generally of the order of 25°C so that in the pre-heat treatment zone, prior to it being discharged therefrom, it’s moisture content is of the order of approximately 35%. it must be appreciated that it is a continuous process and thus‘ the grain is continuously travelling down the kiln. Additionally, hot air is rising within the kiln to provide additional heating. in the pre-heat treatment zone 6, hot air is delivered through the ducts 1 1 (a) and 11 (b) to the valves 1 5(a) and 15(b) respectively. in the initial heat treatment zone 6, due to hot air rising up the kiln, there is usually enough hot air to carry out the necessary drying. Thus, hot air is extracted through the ducts 11(c) and 11(d) and the respective valves 15(0) and 15(d), either for recirculation or delivery directly to atmosphere. it must be_ appreciated that there will be hot air rising in the ducts from the other zones 6 and 7, as will be described later, which zones are directly heated. The amount of air that is removed is such as to maintain the air temperature within the initial heat treatment zone 6 at between approximately 50°C to 60°C and preferably of the order of 55°C, such that the grain moisture content is between approximately 23% and 30% and preferably 27% as it - ieusnszs progresses out the initial heat treatment zone into the upper intermediate heat treatmentzone 7. in the._upper intermediate heat treatment zone 7, hot air is delivered through the duct 11(6) and the valve ‘l5(e) such that the air is at a temperature of between approximately'65°C and 73°C and ‘preferably 68"_C so as to ensure that a grain moisture content of between approximately 10 and 14% and preferably 12% is provided at discharge as it moves into the lower intermediate heat treatment zone 8. in the lower intermediate heat treatmentzone 8, hot .air is extracted through the_ duct 11(b) and valve 15(b) and recirculated by a heat exchanger to heat the air in the duct 11(e). When removing the air from the lower intermediate heat treatment zone 8, the air temperature is maintained at between approximately 68°C and 75°C and preferably of the order of 70‘?C to ensure that a moisture content of between approximately 5% and 8% is maintained at discharge. Preferably, this moisture content isapproximately 6%. _ ’ '.

Finally, in the final heat treatment zone 9, air is introduced at between approximately 75°C and 90°C and preferably at about 80°C to 82°C into this zone to ensure that a grain moisture content of between approximately 4% and 5%‘ and preferably 4.5% is available when the grain is discharged out onto the conveyor 17 through the outlet valves 18. ' Generally, the rate of discharge of grain is so arranged that the process takes between‘20 and 24 hours from beginning to end. This appears to produce the best . malted barley. it will be appreciated that after the kiln 1 has been emptied for cleaning or maintaining and it is necessary to start up again, not a full quantity of green malt will normally be delivered into the kiln 1, but indeed a full batch could, and then gradually the heating operation takes place progressively upwardsso that initially effectively. the pretreatment operation takes place in the final heat treatment zone, followed by the’ , treatment that would normally take place in the pre-heat -treatment zone 6 and V successively the upper intermediate heat treatment zone 7, the lower intermediate heat treatment zone 8 and the final heat treatment zone 9, each time adding additional green malt. in this way, when the grain in the final heat treatment zone 9 is at the required moisture content, discharge "takes place and the operation is then ; , ilE"3"525 commenced on a continuous basis.

By using a pre—treatment operation, quite surprisingly, a much more efficient operation has been achieved and since there is a relatively large amount of heat available, the heat used is effectively "free" heat which adds additionally to the efficiency of the operation. However, it is surprising that the actual quality of the kilned malt is decidedly of better and more consistent quality than heretofore. in the specification -the terms "comprise, comprises, comprised and comprising" or any variation thereof and the terms "include, includes, included and including?‘ or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa. A T The invention is not limited to the embodiment hereinbefore described, but may be varied in both construction and detail within the scopeofthe appended claims.

Claims (1)

1.CLAIMS A continuous kilning process for germinated barley using a vertical kiln (1) having vertically spaced-apart air inlets and outlets (11) for the control of the temperature of the grain (25) therein, the arrangement of the inlets and-outlets (11) being such as to allow the provision of heat treatment zones within the - kiln,_namely, an enlarged upper pre—heat treatment zone (5) forming. a grain inlet and four descending heat treatment zones, namely, an initial heat treatment zone (6), an upper intermediate ‘heat treatment zone (7), a lower intermediate heat treatment zone (8) and a lowermost final heat ‘treatment zone (9)above a discharge outlet (19), the method comprising controlling the temperature ofthe air within the kiln (1) and the quantities of air introduced and removed from the kiln (11), whereby a predetermined rate of discharge of the grain (25) at a desired moisture content is achieved, the method co_mprising:— ‘ continuously adding the grain to the top of the kiln (1) over a larger area than that of the rest of the kiln (1) to ensure that most of the very moist grain (25) is close to the top of the kiln (1); ' delivering a main supply of pressurised hot air into the kiln (1) at the final » treatment zone (9) in contraflow with the grain (25) to agitate and-mix the grain (25) as it falls through the kiin (1); removing air from the kiln (1)‘for drying and controlling‘ the air temperature asit travels up the kiln (1) and adding to or removing air from the kiln (1) such that the air in the pre-treatment zone is between 20°C and 45°C; reducing the moisture content of the grain (25) rapidly on introduction of the grain (25) into the kiln (1) to ensure that the grain (25), on discharge ‘into the initial heat treatment zone (6), has a. moisture content of between 33% and 37%; maintaining the air temperature in the initial heat treatment zone (6) at between 50 and 60°C and the grain moisture content at between 23% and 30% on discharge; maintaining the air temperature in the upper intermediate zone (7),at between 65 and 73°C to ensure a grain moisture content of between 10% and 14% on discharge; ’ maintaining the air temperature in the tower intermediate zone (8) at between 68 and 75°C and the grain moisture content at between 5% and 8% on discharge; introducing air at between 75°C and 90°C into the final heat treatment -' zone (9) to ensure a grain moisture content of between 4 and_5% on discharge; and ' continuously removing grain (25) from the kiln (1). A kilning process as claimed in claim 1, in which the air temperature in the pre- 5 treatment zone (5) is of the order of 25°C and the discharge moisture content of the grain is of the order of 35%. , - t - 5 » - '- A kilning process as claimed in claim 1 or 2, in which the air temperature and discharge moisture content is of the order of 55°C and 27%; 68°C and 12%; 70°C and 6%; and 81°C and 4.5%; for- the initial, upper intermediate, lower intermediate and final intermediate zones (5, 6, 7, 8 and 9) respectively. A"kilning process as claimed in any preceding ciaim, in which the air temperatures are so controiled as to ensure that the kiining process takes not less than 20 hours and not more than 24 hours. A kilning process as claimed in any preceding claim, in which on start-up and with the kiln (1) empfy, the steps are carried, out ot:- green malt is delivered into the kiln (1); air is delivered into the final zone (9) and the grain (25) treated as if in I the pre-treatment zone (5); ’ A when the grain in the final heat treatment zone (9) would be ready for transfer normally to the inttial heat treatmentzone (6), the batch in the final heat treatment zone (9) islheated as if it were in the initial heat treatment zone (6)‘and the batch in the lower intermediate zone (8) is treated as if it were in the pre-treatment zone (5); and the process is repeated progressively up the kiln (1) until the grain in the final heat treatment zone (9) is ready for discharge when the process is carried out as in any preceding claim.