|Title of Invention||
"A FEED SENSOR SYSTEM FOR A CYLINDER MILL"
|Abstract||The invention relates to feed sensor technology for a cylinder mill (1) , in particular a 4- or 8-cylinder mill of the type normally used in milling for the grinding of cereals. The object is, among other things, to permit constructionally simple product detection in the inlet for feed control. The object is achieved in that a sensor (8) is arranged in the feed drum (2) of the cylinder mill (1) and detects a weight force F of the entering product so a control signal can be issued via a signal generator (9) to the feed arrangement.|
|Full Text||The present invention relates to a feed sensor system for a cylinder mill, in particular a four- or eight-cylinder mill for a mill for grinding grain.
The invention relates to a product feed controller for a cylinder mill, in particular a cylinder mill for milling with an electric sensor, a product feed arrangement with adjustable drive means for the feed and to a method of controlling such a cylinder mill.
For controlling the supply of product in a rolling mill for milling, predetermined skeleton conditions have to be maintained. In other words
a uniform distribution of product over the entire length
of the grinding cylinders
the quantity of product flowing to the cylinder mill in
each case must be processed within permitted tolerances
and variations in supply must be compensated as far as
when the product supply is interrupted the product feed
to the grinding cylinders must be stopped with minimal
delay and the grinding cylinders must at the same time be
For decades,-basic elements such as distributing cylinder and feed cylinders as well as mechanical probes have been successfully used as sensors for precise control of the intake to the grinding cylinders. It is also known to use capacitive sensors on such a probe in the intake according to WO 93/06928, and similarly infrared sensors. A minimum of two sensors is required, but more than six measuring points are. usually provided. The quantity of product flowing to the grinding cylinders can basically be instantaneously adjusted by controlling the speed of the feed cylinders or by
controlling the metering gap between a metering slide and the feed cylinder which is also described or implemented as segment adjustment. In practice, both speed control and segment adjustment are employed.
(Speed control of this type is described, for example, in DE-U- Segment adjustment is described in EP-B-38054.
If the product to be metered has a floury or gritty
constitution, segment adjustment is preferred in practice. On the other hand, speed control has often proven superior in the case of flaked products such as coarse meal. As it basically has to be determined in advance for each cylinder mill which design of feed controller is to be incorporated and subsequent modification does not usually take place, it may happen that individual grinding passages do not have an optimum feed controller. As also described in detail in EP-B-515596, the grinding operation forms the focus of each mill and control of the product feed is of particular importance. It has therefore been proposed that a feed controller be provided with a first mechanical signal generator for a digital signal and a second mechanical signal generator for an analog signal and that justifiable stabilizing effects therefore also be achieved. A mechanism of this type is of limited economic value, is relatively complex and invariably absorbs frictional forces which vary and therefore affect the measured result. A mechanism of this type also leads to an accumulation of product and contamination owing to bridge formation.
It is accordingly the object of the invention to overcome the described drawbacks and to allow constructionally simple detection of product in the inlet which can be integrated directly into an automatic feed regulator. A further object of the invention is to develop a method of controlling a cylinder mill, in particular the product feed.
The product feed controller according to the invention is characterized in that the test signal is produced by a single sensor arranged at the inlet. A resistance strain gauge is preferably used. A control signal which controls the engagement and disengagement of the grinding cylinders or basic adjustments of the product feed is produced by the method according to the invention. Owing to the flow of product, the sensor experiences a static force "component and, depending on the constitution and flow properties (in particular flow rate) of the product, a dynamic force component, proportionally to the quantity of product located over it.
Varying frictional conditions in contact with the product hardly affect the test signal. Contamination which accordingly influences the control signal is virtually eliminated.
The main advantage of the solution according to the invention resides both in technically simple product detection and in unproblematic adaptation, to existing feed controllers, for example according to EP-B-515596. Furthermore, there are no mechanically moving soilable parts.
The on/off point can be detected with a single sensor and the feed can be controlled by the same received signal.
Owing to the possibility for amplification in the known electronic module, only a small force component of the product stream is required and owing to the incorporation of a small sensor, minimal friction is noted.
Accordingly, the present invention relates to a feed sensor system for a cylinder mill, in particular a four- or eight-cylinder mill for a mill for grinding grain, which cylinder mill is provided with a product feeding device with adjustable drive means for the feed cylinders as well as means for the engagement and disengagement and the gap adjustment of the cylinders as well as with means for detecting the product in the inflow, with a sensor being disposed in the product inflow for detecting the weight of the inflowing product, wherein the sensor is provided with only one rod which is arranged transversally or perpendicularly to the direction of flow of the product.
An embodiment of the invention is described in more detail hereinafter with reference to accompanying drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows schematically the basic elements for grinding by means of a cylinder mill.
Figure 2 shows the arrangement of the sensor at the inlet (product intake).
A cylinder mill 1 of the type normally used in milling (for example according to EP-B-334919 or DE-C-2730166 contains, among other things, a feed drum 2 with a product feed chamber 3 having, in the lower part, a distribution cylinder 4 and a feed cylinder 5 which can be rotated in the same direction via a gear mechanism 6 and drive means 7.
On the feed drum 2 there is arranged a sensor 8 which is directly connected to a transducer 9 or can be assembled as a unit. A weight force F is transmitted as a signal to the transducer 9 by means of the sensor 8 . The weight force F itself acts on the rod 10 of the sensor 8 . The sensor 8 measures this force and conveys this information to the transducer 9, wherein resistance strain gauges (DMS) can also be used on the rod 10 or as a rod 10. The transducer 9 is connected to the feed arrangement directly or via a transducer 14.. The sensor 8, 10 can be arranged at basically any position in the feed cylinder 2 or product feed chamber 3 in front of distribution and feed cylinder 4, 5. It is conceivable in individual cases to provide a second sensor 8, for example if very high requirements are imposed on the feed controller and/or under complicated product flow conditions.
The rod 10 of the sensor 8 is mounted in a dust-tight and articulated manner in a wall of the product feed chamber 3.
A feed gap 11 is formed by a segment 12, a segment adjusting arrangement 13 being shown schematically. Two basic adjustments are possible, either the speed of the feed cylinder 5 or the position of the feed segment 12 being influenced by the signal from the sensor 8 and a transducer 14 via connections 15 and 15' shown in broken lines.
"The sensor (8) comprises a cantilever rod (10) supported
at one end by a mounting, and extending through the wall
(25) of the feed drum so that the free end of the rod (10)
is positioned within the feed drum (2). , The rod (10)
extends in a direction substantially perpendicular to the
direction of flow of the product through the feed drum
(2)."The product discharged in the feed cylinder 5 is accordingly (arrow 16) supplied to a pair of grinding cylinders consisting of a fixed cylinder 18 and an idle cylinder 17. The idle cylinder 17 is allocated an engagement and disengagement device 19 controlled as a function of a control signal from the sensor 8 via a control line 20. The idle cylinder 17 is also allocated a grinding gap adjusting device 21 which is adjustable by hand wheel 22 or via motor means 23 and an electronic memory/computer unit 24. This is carried out in dependence on or as a function of the specific grinding work, the quality of the ground product or the throughput of product through the cylinder mill 1.
The actual feed control is carried out, for example, via the type of pneumatic or electric adjustment, known from (EP-B-38054 of the feed segment 12 or of the feed gap 11 or speed control. Engagement and disengagement are controlled pneumatically or electrically.
1. A feed sensor system for a cylinder mill (1), in particular a four- or eight-cylinder mill for a mill for grinding grain, which compresesa cyllnder mill with a product feeding device with adjustable drive means for the feed cylinders (4,5) as well as means for the engagement and disengagement (19) and the gap adjustment of the cylinders (17,18) as well as with means for detecting the product in the inflow, with a sensor being disposed in the product inflow for detecting the weight (F) of the inflowing product, wherein the sensor (8) is provided with only one rod (10) which is arranged transversally or perpendicularly to the direction of flow of the product.
2. A feed sensor system as claimed in claim 1, wherein the rod (10)
projects into a feed cylinder (2).
3. A feed sensor system as claimed in claims 1 and 2, wherein the
rod (10) is disposed perpendicularly to the wall of
the feed cylinder (2).
4. A fees sensor system as claimed in one of the claims 1 to 3,
wherein the sensor (8) is connected with a signal converter (9) or
forms a module with the same.
5. A feed sensor system for a cylinder mill substantially as herein
described with reference to and as illustrated in the
|Indian Patent Application Number||1201/DEL/1998|
|PG Journal Number||11/2008|
|Date of Filing||05-May-1998|
|Name of Patentee||BUHLER AG|
|Applicant Address||CH 9240 UZWIL, SWITZERLAND,|
|PCT International Classification Number||B02C 25/00|
|PCT International Application Number||N/A|
|PCT International Filing date|