HYDRAULIC CONTROL FOR A FOOD BAKING APPARATUS

Abstract

The invention relates to hydraulic control for carrying out a method of producing a cracker from cereals, which are pressure-baked in a heated mold and expanded afterwards. In particular the hydraulic control system, comprising of a plurality of hydraulic cylinders, will lead to an increased expansion speed or an increased speed for opening the dies, resulting in constant high-quality food products.

Claims

1-7. (canceled)

8. A food baking apparatus comprising: a hydraulic drive system comprising at least three hydraulic cylinders; and two dies at an adjustable distance (d) from each other, the two dies being configured for a food product to be baked between the two dies, the two dies being operable to be opened or closed by adjustment of the adjustable distance (d) by the hydraulic drive system, wherein: each of the at least three hydraulic cylinders comprises a double-acting piston and a position sensor; each of the at least three hydraulic cylinders has a respective stroke; and the at least three hydraulic cylinders cooperate with one another and are fixedly joined to one another in line in an integral block assembly determined by a length L; the adjustable distance (d) is adjusted by moving one or more of the at least three hydraulic cylinders for further opening or closing the dies; and at least two of the at least three hydraulic cylinders in the integral block assembly are simultaneously movable from the position sensor till the end of the respective stroke toward each other, thereby shortening the length L of the integral block assembly.

9. The food baking apparatus of claim 8, wherein at least one of the at least three hydraulic cylinders is provided for adjusting the adjustable distance (d), herewith positioning the dies relative to each other.

10. The food baking apparatus of claim 8, wherein at least two of the at least three hydraulic cylinders is operable to generate expansion room in between the dies while increasing the adjustable distance (d).

11. The food baking apparatus of claim 10, wherein at least one of the at least three hydraulic cylinders is provided for adjusting the adjustable distance (d), herewith positioning the dies relative to each other.

12. A method for hydraulically controlling a food baking apparatus comprising two dies at an adjustable distance (d) from each other, the two dies being configured for food to be baked between the two dies, the two dies being operable to be opened or closed by adjustment of the adjustable distance (d) by a hydraulic drive system, the method comprising: providing the hydraulic drive system with at least three double-acting hydraulic cylinders each having a respective stroke; providing each of the at least three double-acting hydraulic cylinders with a respective position sensor; mounting the at least three double-acting hydraulic cylinders in line in an integral block assembly having a length L; moving one or more of the at least three double-acting hydraulic cylinders for adjusting the adjustable distance (d), thereby further opening or closing the dies; and simultaneously moving at least two of the at least three hydraulic cylinders in the integral block assembly from the respective position sensor optionally till the end of the respective stroke towards each other, thereby shortening the length L of the integral block assembly.

13. A food baking process with hydraulic control, the food baking process comprising: providing a food product between the two dies of a food baking apparatus according to claim 8; and baking the food product with the food baking apparatus.

14. The food baking process of claim 13, wherein baking the food product comprises: moving one or more of the at least three hydraulic cylinders for adjusting the adjustable distance (d), thereby further opening or closing the dies; and simultaneously moving at least two of the at least three hydraulic cylinders in the integral block assembly from the respective position sensor optionally till the end of the respective stroke towards each other, thereby shortening the length L of the integral block assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 illustrates hydraulic drive system of a food baking apparatus according to the art.

[0018] FIG. 2 illustrates an embodiment of the hydraulic drive system in accordance with the invention.

[0019] In FIG. 2 (a) a hydraulic drive system comprising three cylinders is shown. In FIG. 2 (b) such hydraulic drive system is depicted again, but now sensors provided onto the cylinders are also indicated.

[0020] FIG. 3 illustrates an embodiment of the dies in closed position in accordance with the invention.

[0021] FIG. 4 illustrates an embodiment of the dies in open position in accordance with the invention.

[0022] FIG. 5 illustrates a flow-chart embodiment of the hydraulic drive system operation in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0023] As described in the background above, the speed of opening of the dies has an important influence on the baked food product. In order to increase this speed, and hence achieve higher opening speeds of the dies on a hydraulically driven food baking apparatus, several technical solutions are initially considered. One can think of for example using hydraulic pumps with higher oil flow, however this seems not an adequate solution. Picking up the signal of the position sensors on the hydraulic cylinders, for controlling movement thereof and particularly for a fixed starting position of the inward movement, becomes very inaccurate. Alternatively, higher oil pressures could be applied, however only leading to considerable pressure spikes and the opening of the overpressure valve in the hydraulic circuit.

[0024] The present invention is related to providing extra hydraulic effect or force to be exerted for increasing the speed of opening of the dies, and hence speeding up the expansion. The present invention is therefore related to the use of an additional hydraulic actuator, comprising of a double-acting hydraulic cylinder, being mounted in line with the—in accordance with the art—existing double-acting hydraulic cylinders. In the art, the existing double-acting hydraulic cylinders, more in particular of which two being used, are mounted back-to-back in a hydraulic block assembly.

[0025] According to an embodiment, the extra double-acting hydraulic cylinder is mounted in line with and as an extension of the existing double-acting hydraulic cylinders.

[0026] As mentioned earlier, in accordance with the art as depicted in FIG. 1, illustrating a hydraulic drive system 10 comprising of two double-acting cylinders 11, 12 mounted back-to-back, the generation of expansion room or opening of the dies is achieved by the inward movement of the cylinder 12 from the position sensor till the end of its stroke. According to an embodiment of the invention, FIG. 2 (a) illustrates a hydraulic drive system 20 comprising of three double-acting cylinders 21, 22, 23 wherein the cylinders 21, 23, also referred to as outer cylinders 21, 23, are provided at the outer ends of the in line assembly of the three cylinders and the cylinder 22, also referred to as middle cylinder 22, being provided in between thereof. The middle cylinder 22 is merely used to position the lower die in the different positions needed for e.g. dosing starchy materials, and removing the finished product or cracker, and accordingly provides the respective positioning of the dies independent of the generation of the expansion room or opening of the dies therefor. The three cylinders 21, 22, 23 are connected, while cooperating and being fixedly joined to one another in line, defining an integral block assembly having a length L. The three cylinders comprise each a position sensor, and each have a respective stroke. The generation of expansion room or opening of the dies is now achieved by a simultaneous inward movement of both outer end cylinders 21, 23 both moving inward from their respective position sensor till the end of their respective stroke, thereby shortening the length L of the integral block assembly. This is leading to an increased (e.g. doubled) opening force and thus much higher opening speed of the dies. As a result, more expansion, and hence a higher product thickness can be achieved. While achieving a higher opening speed of the dies in this way, an accurate picking up of the signal of the position sensors on both outer cylinders and particularly the fixed starting position of the inward movement of both outer cylinders, is moreover retained. This means that the food baking apparatus will produce food products with very even thickness, shape and texture, or else constant quality over time.

[0027] According to an alternative embodiment, the outer cylinders 21, 23 from FIG. 2 (a) can also be mounted back-to-back next to each other, while having the middle cylinder 22 then positioned at one of the outer ends, for example where the outer cylinder 23 is presented in FIG. 2 (a). Although having the individual cylinders positioned in another sequence, the hydraulic effect of the alternative design, generating either expansion, either being responsible for the positioning of the dies, will be the same as compared to the architecture of FIG. 2 (a). In other words, as long as one of the three cylinders is provided for the positioning, and two cylinders are provided for the expansion, a similar hydraulic effect resulting in higher opening speed of the dies, and hence more airy and thicker crackers after baking, will be achieved.

[0028] The use and impact of the sensors provided onto the cylinders is now further explained. FIG. 2 (b) illustrates the hydraulic drive system 20 comprising of three double-acting cylinders 21, 22, 23 as shown in FIG. 2 (a) but moreover indicating the sensors 1, 2, 3, 4, 5, 6 being provided in pair onto the cylinders 21, 22, 23 respectively. Each cylinder comprises two sensors: for cylinder 21 the sensors 1, 2 are foreseen, cylinder 22 is provided with the sensors 3, 4 and onto cylinder 23 the sensors 5, 6 are mounted. The outer cylinders 21, 23 can simultaneously move and open, and herewith achieve faster movement, i.e. opening or closing, of the dies where in between food is baked. The outer cylinder 21 moves from sensor 1 in the direction of sensor 2, whereas the outer cylinder 23 moves from sensor 6 towards sensor 5 during inward movement. The entire or total stroke (length) being accomplished by both cylinders is thus the combination of the two stroke lengths respectively from sensor 1 to sensor 2, and from sensor 6 to sensor 5 respectively. It is noted that only the sensors 1, 6—also called position sensors—can be adjusted in position in order to achieve the total stroke length. The sensors 2, 5 are always positioned at the end point of their respective cylinder inward stroke. In fact, at this inward stroke of these respective cylinders 21, 23, i.e. the moment when food in between the dies is expanded, it is fairly impossible to have the cylinders terminated in a reliable and repetitive way elsewhere than at the end of their stroke length, determining the mechanical (or physical) end anyhow.

[0029] For a particular adjustment of the sensors 1, 6 of the respective cylinders 21, 23, the food baking apparatus operates with regular behavior delivering a constant quality end product e.g. cracker. In other words, a constant thickness can be achieved, and hence not producing a mix randomly with much thinner and much thicker crackers.

[0030] This means that, actually, the sensors 2, 5 are not particularly needed for adjustment and positioning, but are only used here for feedback notification to the PLC, indicating for example that the cylinders are at the end of their inward movement. If not, alternatively, the cylinders can be put in this end position at the start or beginning of operating the machine.

[0031] The sensors 3, 4 from cylinder 22 also do not intervene in realizing the expansion stroke of the machine, i.e. food baking apparatus. Instead, the cylinder 22 and corresponding sensors 3, 4 are responsible for the positioning of the dies, e.g. at ejection of crackers or when new raw material is brought into the machine to be baked.

[0032] According to a further embodiment, more than three cylinders are provided and are positioned in a random sequence, for generating either expansion as well as providing positioning of the dies. In accordance with the invention, amongst the at least three or more than three cylinders, at least one cylinder is provided for the positioning, whereas the two or more other cylinders are intended for generating expansion.

[0033] Depicted in FIGS. 3 and 4 are the dies 31, 32 either in closed or in open position respectively, for which the time needed for moving from one position (e.g. closed as illustrated in FIG. 3) to the other (e.g. open as illustrated in FIG. 4), or vice versa, is significantly less as compared to the art. For FIG. 4, where the dies 31, 32 are shown in open position, a distance d between the upper dies 31 and lower dies 32 is indicated. Moreover, the speed using hydraulics, for moving positions of the dies including the ability and/or flexibility in expansion of grain or cereal material there in between, is comparable with pneumatic system's high speed, in accordance with the invention.

[0034] Referring now to FIG. 5 wherein a flow-chart embodiment of the hydraulic drive system operation 500 in accordance with the invention being illustrated, in particular the cylinders operation causing an effect on the position of the lower die 32, and hence on the distance d between the dies 31, 32. At the same time is here referred to the embodiment of FIG. 2 for the installation of the hydraulic drive system 20 and its cylinder 21, 22, 23, wherein the middle cylinder 22 is merely meant for positioning of the lower die 32, whereas cylinders 21, 23 are intended for generating expansion room, or compression between the dies 31, 32. The hydraulic drive system operation 500 with focus on the cylinders operation, is now described starting with block 501, for initiating the operation, i.e. turning on the hydraulic drive system 20 with manifold block of cylinders 21, 22, 23, being connected with the movable punch, or lower die 32. Block 502 represents questioning whether (i) the position of the lower die 32 needs to be adapted or fine-tuned for bringing in starchy material, or taking out the (finished) cracker, or else (ii) if compression or expansion is required for the material to be baked being provided between the dies. In case of (i) merely for positioning the lower die 32 because material has to be placed in between or removed from the dies 31, 32, block 503 is to be continued with, for moving the cylinder 22 either inwardly or outwards. As a result, as indicated by block 504, the lower die 32 being connected with the cylinders manifold, will move up or down. There is no particular force or speed or any other parameter involved or needed for performing this positioning of the lower die 32 with cylinder 22. Block 505 represents that the distance d between the dies 31, 32 thus being changed. Following now the right part of the flow chart of FIG. 5, i.e. in case of (ii) expansion or compression for the material to be baked being selected during the baking process, block 506 is to be continued with, for moving both cylinders 21, 23 simultaneously inwardly or outwards. However, this is not done in an arbitrary manner, but performed such that moving up or down of the lower die 32, is done at a particular speed v (e.g. for expansion) and/or with a particular force F (e.g. for compression), as represented by block 507. The distance d between the dies 31, 32 again being changed, being represented now by block 508.

[0035] According to an embodiment of the invention, the hydraulic cylinder unit design of a standard rice cake machine, such as the Incomec Cerex Processor, is altered to be made up of three hydraulic cylinders instead of two hydraulic cylinders in order to allow for a higher end expansion speed in a repeatable and controllable way. The third cylinder is specifically designed for this purpose. The hydraulic manifold block designed to control three hydraulic cylinders, allows for a hydraulic control operation, resulting in a higher end expansion speed in a repeatable and controllable way as mentioned above.