WO1991012736A1

WO1991012736A1 - Method and apparatus for treating cloves for use as smoking material

Info

Publication number: WO1991012736A1
Application number: PCT/GB1991/000318
Authority: WO
Inventors: Victor Albert Montgomery White; Derek John Hall
Original assignee: Gbe International Plc
Priority date: 1990-03-02
Filing date: 1991-03-01
Publication date: 1991-09-05
Also published as: GB9004709D0

Abstract

A process for the production of smoking material from cloves comprises the steps of a) conditioning the cloves by heating and steaming, b) thereafter effecting rolling of the cloves to flatten the cloves, c) cutting the cloves by means of a cutting machine (12) of the kind having converging compression bands (16, 17) for conveying the flattened cloves towards a mouthpiece (18), and a cutter (19, 20) passing the mouthpiece, and d) drying the resulting material. Preferably, the apparatus for carrying out the above process comprises a) a conditioner (10) for conditioning the cloves by heating and steaming, b) a machine (11) for rolling the cloves to a flat state, c) a cutting machine (12) of the kind having converging compression bands for conveying the flattened cloves towards a mouthpiece, and a cutter passing the mouthpiece, and d) a drier (13) for drying the cut cloves.

Description

METHOD AND APPARATUS FOR TREATING CLOVES FOR USE AS SMOKING MATERIAL

This invention concerns the production of KRETEK cigarettes and in particular the preparation of cloves for inclusion in the cigarettes.

The KRETEK cigarette is flavoured with the spice clove. Typically the KRETEK cigarette contains 20 to 405& of prepared cloves, with the remainder being comprised of processed tobaccos. The distinctive flavour of KRETEK cigarettes results from the presence of clove oil, of which a major component is phenol eugenol . Clove o l is highly aromatic and volatile. For many industries advantages of the volatile nature of the oil is taken by using steam distillation or solvent extraction processes to remove the oil from the cloves, so that it can more conveniently be re- incorporated in manufactured foodstuffs and pharmaceuticals.

The volatile nature of clove o l is a disadvantage in KRETEK manufacture since loss of aromatics in process cause a diminution of aromatics in the final cigarette or a need to increase^' the clove content to maintain a particular cigarette flavour.

The major use of clove is as an inclusion in KRETEK cigarettes. Since cloves are an agroπometric product the availability of supply and oil quantity vary with weather conditions and other agronometπc influences.

Established clove processes for KRETEK have a umber of disadvantages of which the principle ones are: high loss of aromatics and high loss of mass. Other disadvantages include: labour intensive processing, long process time delays, use of large floor areas and the production of particle sizes incompatible with modern cigarette making methods.

This invention contributes substantially to the reduction of these disadvantages.

Cloves are harvested as flower buds with elongated inferior ovule and then dried for storage. This drying stage is frequently carried out in the sun.

The major stages in traditional factory processing are conditioning, cutting and drying prior to inclusion in tobacco for cigarette manufacture.

At the conditioning stage cloves are placed in water baths where they can remain for several hours. In some installations they are dragged through the water by mesh and pin conveyors. After soaking for about 5 hours they are allowed to drain again for a substantial time period, usually overnight. Prior to the conditioning their moisture content could be as low as 4% or range up to about 14%. After conditioning and draining the moisture content could range up to 50% and typically be 46%.

Conditioning is by slow absorbtion of water. Both the rate of absorbtion and the final moisture content, given sufficient absorbtion time, are dependent on the type of clove, how it was grown and dried. The water baths contain far more water than is required for absorbtion by the clove, hence some clove oil is lost by solution into the water.

The traditional moisture content for clove cutting is typically 40 to 48%. That is slightly below the moisture consequent on the soaking and draining conditioning process. The cloves are cut using a special cutter comprising a drum rotating about a horizontal axis with a grooved surface and a fixed cutting blade placed close to the drum and lying parallel to its surface. In operation cloves feed into the cutting machine close to the cutting blade and tend to align into the grooves and are drawn past the cutting blade. In this way the clove is cut parallel to its axis rather than transversely. The generated cut particle size is dependent on the groove depth and blade clearance about the drum. Fine cuts will reduce the mass of cloves cut in a given time. Since most clove cigarettes are handmade rather than machine made, a course cut is used. This gives particles which tend to be too large for cigarette making machines. If presented to cigarette making machines, some of the cloves would be rejected by the machines' classification system, while those entering the cigarette could result in torn wrapping paper. For machine made cigarettes it is normal to either re-cut the already cut cloves or to operate at finer cuts initially.

Typically each cutter is able to process about 50 to 150 kg per hour so that 10 to 40 cutters are required for an output of 2000 kg/hour. The cutter blades cannot be sharpened while cutting and in consequence the cutters are frequently stopped to remove blades for sharpening and to fit sharpened blades.

Following cutting the cut product must be dried down to the region of 10 to 50% typically 13 to 14% for inclusion in the tobacco feed stock. Traditionall the product is laid out in the sun for about 16 hours for drying and during drying is turned over by hand. This method is very consumptive of space, labour and time. Of recent years the industry has moved towards the use of fluidised bed and band driers. In the former the product to be dried typically passes through a vibrating trough and hot air passes through the cut clove mass. In band driers the clove mass is supported on a band which can be perforated. Hot air is then passed over or through the band and product. In both instances the air volume and temperature is such that it can supply the heat required for moisture liberation and carry away the liberated vapour. Typically this system could employ about 270 cubic metres per minute of air heated to about 190° in order to dry 2 tonnes/hour of cloves from 50% to 13% moisture. That is 270 cubic metres/minute of air at 190° to liberate 850 kg per hour of water vapour, or 19 cubic metres of a r per kg of water vapour, or 14 kg of a r per 1 kg of dry cloves. Both the volume and temperature of the air encourage liberation and removal of volatile clove o ls, in a way similar to steam (water vapour) distillation.

It is an object of this invention to provide a method of processing cloves which operates at lower conditioning moisture contents, enables higher cutting throughputs per machine, presents less risk of loss of volatile oils, while also requiring less process time, labour and area.

According to the invention there is provided a process for the production of smoking material from cloves comprising the steps of a) conditioning the cloves by heating and steaming, b) thereafter effecting rolling of the cloves to flatten the cloves, c) cutting the cloves by means*of a cutting machine of the kind having converging upper and lower compression bands for conveying the flattened cloves towards a mouthpiece, and a cutter passing the mouthpiece, and d) drying the resulting material.

Preferably the invention uses a screw conditioner to condition the cloves, a rolling system to flatten the cloves, a rotary cutter to cut the cloves and preferably a rotary drier to reduce the product moisture content. If the input product is believed to be contaminated with dusts and heavy objects such as stones, the invention may first be preceded by a cleaning stage, such as a short duration water bath or an airlift separator.

In the accompanying drawing there is shown schematically an embodiment of the apparatus for carrying out the invention, which comprises a screw conditioner 10, a roller 11, a rotary cutter 12 and a rotary drier 13.

Each of the stages of the invention has been tested separately and in combination with each other. It has been shown that a very satisfactory product is obtained from the total invention when the cloves are initially conditioned to 33 to 38% moisture which using the proposed drying method requires 2.7 cubic metres of air per kg of dried product.

For a line producing 1150 kg of dried clove at 13% moisture the following comparative figures are as follows:

CONVENTIONAL INVENTION

Moisture Added 877 415 KG (from input) To Give: (at 11%)

Cutting Moisture 50 35

Water Removed 850 388 KG In Drying

Drier Air Flow 270 24 Cubic Metres

Air Temp. Up To 190 120 Degrees

Air Flow Per Cubic Metres

Kg Of Water Removed 19 3.6 Per Kg

Air Flow Per Kg Cubic Metres Of Dried Cloves 14 2.7 Per Kg

Dried Clove

Mass Flow at 13% M 1150 1150 Kg/Hour

Clearly the invented process involves greatly reduced water removal and hot air exposure and in consequence a signif cantly reduced loss of volatiles during conditioning and drying.

This enables conditioning to be achieved in 30 seconds to 3 minutes (compared to 5 hours in the traditional method). In the process the product is not exposed to large amounts of surplus water in which volatiles could dissolve. Water is sprayed onto the cloves which are transported via a screw through a trough. Steam is applied through the base of the trough. By this means water and energy to enable the water to penetrate the clove are applied nearly concurrently. Good penetration of water into the clove is obtained without having to allow the clove to become water saturated and without leaching out solubles.

It is well known in tobacco processing that rolling of stem-like items aids cutting and that both are heavily dependent on the use of correct conditioning moisture and its penetration to the core of the material being processed. With a view to application of a rolling process to cloves it was at f rst thought to be unsuitable because of the likely degradation resulting in a preponderance of small particles and the possibility that particles would be pulled out of the "cheese" at the mouth of the cutting machine during the cutting stage. However, a rolling stage has been found by the inventors to be surprisingly satisfactory when followed by cutting under carefully controlled conditions.

The rolling stage utilises a machine 11 such as the Legg SRM range for rolling tobacco stem. The conditioning stage may be a screw conditioner 10 of the kind described in International Patent Publication No WO 90/13231.

The cutting stage utilises a machine such as the Legg MM or SS range for cutting tobacco and described in GB Patent No 1 067 448. Depending on the selected cutter size and type, throughput of up to about 2000 kg/hr per cutter can be obtained. Trials conducted without rolling yield a proportion of poorly cut material which was judged unacceptable. The introduction of rolling prior to cutting enables a more coherent compaction of the clove mass to form a cheese, or compressed mass, in the cutter.

A tobacco cutter 12 includes a pair of converging bands 16, 17, one above the other, which feed tobacco through a mouthpiece 18 into the path of cutting knives 19 rotatable by a drum 20. The upper band 16 is carried in a movable carriage 16a, which is pivoted at its feed end but is free to rise and fall at its delivery end. An air cylinder 21 applies thrust to the delivery end of the carriage and associated upper portion of the mouthpiece, so as to compress the tobacco.

It was found that for best results an additional thrust was desirable in order to maintain a coherent mass ("cheese") of cloves in the mouthpiece; for example, in the tests referred to above the width of the mouthpiece was 406 mm and the diameter of the air cylinder was 203 mm. For cutting tobacco stem an air pressure of 4 bar in the air cylinder is satisfactory giving a thrust at the mouthpiece of the cutting machine of 66 N/mm of width of mouthpiece. For cutting cloves an air booster was itLeri and an air pressure of 7 to 8 bar was required in the air cylinder giving a thrust of 85 to 97 N/mm of width of mouthpiece, an appropriately larger air cylinder 20 being provided compared with that used for tobacco cutting.

The drying stage utilises a rotary drier 13 such as the Legg single cylinder type TC drier described in GB Patent No 1209929 or the Legg double cylinder annular drier as described in GB Patent No 1 345373 and as now improved by a lipped paddle, International Patent Application No PCT/GB90/101688. Trials were carried out in a lrier specifically constructed to investigate and optimise drying regimes for various products. This involved the conducting of a series of tests and their analysis using multiple regression techniques. The drying regime derived supplies 10 to 30% of the heat required for moisture liberation from the air stream with the remaining 70 to 90% of the required heat being supplied via heated surfaces within the drier. This compares with near 100% of the required heat being supplied via the air in a fluidised bed or band or sun drying.

During experiments and trials tests were conducted with

MOISTURE 38 TO 46 %

ROLL GAP 0.01 TO 0.035 INCH (0.24 - 0.84 mm) AND WITH NO ROLLING

CUTTING 28 TO 120 CUTS PER INCH (0.91 to 0.21 mm width of cut)

DRYING 60 TO 120 ^*C Preferred process settings were:

MOISTURE 36% WITH PRODUCT AT 65 TO 80 ^*C

ROLL GAP 0.035 INCH (0.089 mm) WITH WARM PRODUCT

CUTTING 40 TO 50 CUTS PER INCH (0.64 - 0.51 mm width of cut)

DRYING BELOW 120 C^*

TYPICAL PHYSICAL RESULTS WERE:

LEGG PROCESS TRADITIONAL PROCESS-

MOISTURE 32 TO 37 41 TO 45 % ROLL GAP 0.035 INCH (0.089 mm) NO ROLLING CUTTING 40 TO 50 CUTS PER INCH 1st CUT 22 CPI (1.14 mm (0.64 - 0.51 mm width of cut) width of cut)

2nd CUT 28 CPI (0.89 mm width of cut)

SIEVE RETENTION

OVER 2.8 MM 2.9 2.4 2.5

0.71 TO 2.8 MM (DESIRED SIZE) 89.9 89.1 86.8

BELOW 0.71 MM 7.2 8.5 10.7 %

The present invention yielded about 89.5% of product in the des red size range compared to 86.8% for the traditional process. That is an improvement of 2.7%. The desired range is defined from a number of factors. One relevant factor is the effect of combustion on released flavour; small particles combust more readily and release flavour. This is in part due to their size and in part to the way in which they pack into the cigarette. Below a certain size it becomes increasingly difficult to retain particles in the cigarette and a significant proportion of small particles will be lost in the process and cannot contribute therefore to the final cigarette.

From the results for the conventional process in order to contribute 86.8 units to cigarettes, 10.7 units are at risk of loss, or to contribute 100 unit the loss risk is 12.3 units. With the invention to contribute 89.5 units involves a loss risk of 7.9 units, or for 100 units to cigarettes, 8.8 units loss risk. Hence comparing the ol-d and new processes for the same cigarette contribution, the loss risk falls from 12.3 to 88. units which is a 29% relative improvement. In terms of the quantity of cloves required to be purchased to satisfy the numbers of finished cigarettes then the purchased quantity falls from 112.3 units to 108.8 units giving a saving of 3.1%. These figures assume that the aromatic oil content of the processed cloves is the same for both traditional and new processes. With the new process, aromatic losses are no greater and can be substantially less than in the traditional process.

This increases the saving to be made by further reducing the quantity of processed cloves required in a cigarette in order to generate the targeted smoking flavour.

Claims

CLAIMS :

1. A process for the production of smoking material from cloves comprising the steps of a) conditioning the cloves by heating and steaming, b) thereafter effecting rolling of the cloves to flatten the cloves, c) cutting the cloves by means of a cutting machine of the kind having converging upper and lower compression bands for conveying the flattened cloves towards a mouthpiece, and a cutter passing the mouthpiece, and d) drying the resulting material .

2. A process as claimed in claim 1 wherein the above steps a) - d) are preceded by cleaning the cloves in a water bath to remove dust and heavy particles.

3. A process as claimed in claim 1, wherein the above steps a) - d) are preceded by cleaning the cloves in an airlift separator to remove dust and heavy particles.

4. A process as claimed in claim 1, 2 or 3, wherein the cloves are conditioned [step a)] to 33 to 38% moisture content.

5. Apparatus for the production of smoking material from cloves, comprising a) a conditioner for conditioning the cloves by heating and steaming, b) a machine for rolling the cloves to a flat state, c) a cutting machine of the kind having converging upper and lower compression bands for conveying the flattened cloves towards a mouthpiece, and a cutter passing the mouthpiece, and d) a drier for drying the cut cloves.

6. Apparatus as claimed in claim 5, wherein the conditioner is a screw conditioner.

7. Apparatus as claimed in claim 5 or 6, wherein the rollers of the machine for rolling the cloves are set to a gap of 0.01 to 0.035 inches (0.25 - 0.89 mm).

8. Apparatus as claimed in claim 5, 6 or 7, wherein the cutting machine has a plurality of blades mounted on a rotary drum, said blades being constantly sharpened during operation of the cutting machine.

9. Apparatus as claimed in claim 8, wherein the upper compression band is mounted on a carriage pivoted at one end, an air cylinder capable of effecting a thrust at the mouth of the cutting machine of from 85 N/mm to 97 N/mm of width of mouthpiece.

10. Apparatus as claimed in claim 8 or 9, wherein the drum rotation speed and band speed feed are arranged to give 40 to 50 cuts per inch (0.64 - 0.51 mm width of cut).