Field of the invention
The present invention relates to an on-line counting of biscuits in stacks before packing in
packaging machines.
More particularly, the present invention relates to a system and method for counting
biscuits on packaging machines comprising optical sensor installed to sense the trailing.
and the leading edge of the biscuit moving in a stack at the defined linear speed of
packing machine.
Background and prior art
Conventionally, in the bakery industry, the net weight of a pack is defined by the weight
of individual biscuit and subsequently the number of biscuits going to be packed in each
packet.
The discrimination between a standard pack and over or under weight pack is done by
online weighing machine, which detects and rejects such packets. However, the prior
method of discrimination leads to the limitations that due to variation in the biscuit
thickness the number of biscuits may vary irrespective of defined set weight of each
packet.
Thus there was a need to develop an improved system and method for counting biscuits
on packing machine before packing in a predefined packet providing striking appearance
of a packet as the number of biscuits will always be intact as predefined.
Objects of the invention
It is an object of the present invention to overcome the drawbacks of the prior art.

It is another object of the present invention to provide a system and method for counting
individual biscuits in stack moving on a packing machine going to be packed in a desired
packet and is essential to provide accurate number of biscuits in a pack going into the
market.
It is yet another object of the present invention to provide a feasible, reliable and
repeatable method at a desired conveyor speed of 30 m/min.
Summary of the invention
The present invention relates to a system for counting plurality of biscuits in a stack
wherein said system consists of a combination of online optical sensors to detect biscuits
ori high speed moving conveyor of packing machine.
Detailed description of the accompanying figures
The present inventors have found that a system and method for counting biscuits wherein
optical sensors are installed to sense trailing and leading edge of the biscuit moves in a
stack at the defined linear speed of packing machine. Accordingly, the present invention
relates to a method for counting biscuits in a stack at a defined linear speed of packing
machine & rejecting the desired.
The invention is now described with reference to the drawings
Counting Station:
The counting station comprises of an optical sensor (7) installed to sense the trailing and
the leading edge of the biscuit moving in a stack (6) at the defined linear speed of
packing machine. The stack of biscuits is allowed to pass in front of a set of analog
optical sensor (7) comprising of emitter (7) and receiver (7). The light passing through
the rising and the falling edge of the biscuit is sensed by the analog receiver, which gives

output proportional to the intensity of light falling on the receiver. This generates a
sinusoidal electrical waveform of different peak values depending upon the magnitude of
light being passed in between the two biscuits. This waveform is further analyzed and
subsequently the logic is developed in PLC to count the lows and highs of the waveform
and to totalize them to convert into number of biscuits present in the stack.
Basis on the present numbers of biscuits in particular pack, substandard packet is been
isolated and prevented from being packed. The rejection station (figure 6), an integral
part of the counting mechanism, comprises of a pneumatic cylinder mechanism, which is
being controlled by the same PLC and is actuated on the basis of the go and no go logic
defined in the PLC program. At various machine speeds, the packet is continuously being
tracked by the help of encoder mounted on the main motor shaft and incorporated to
detect and reject the desired packet
The rejection prevents the substandard packets to reach to the customer & gives clue to
the process control system to maintain the correct dimensions of the product.
Prior to this invention final product was tested by online check-weigh machine, which
used to validate the weight of the packet irrespective of nos. of biscuits inside.
STEM
The stack of biscuits is allowed to pass in front of a set of analog optical sensor
comprising of emitter and receiver. Levelers (1, 2, 3) are provided to support the biscuit
stacks (6) for proper sensing (figure 3).
STEP-2
Figure 4 demonstrates the back view of the index sensor setup. Index sensor fixed in the
bottom helps in initialing the sensor at each time stacks comes to that position. After
receiving signal from this Proxy sensor (7), counting sensor starts counting.

STEP-3
Counting happens here only after receiving signal from proxy sensor (7) (figure 5)
STEP-4
Figure 6 demonstrates the exit-conveyor rejection setup. The rejection station comprises
of a pneumatic cylinder mechanism, which is being controlled by the same
PLC/Microprocessor and is actuated on the basis of the go and no go logic defined in the
PLC/Microprocessor program. At various machine speeds, the packet is continuously
being tracked by the help of encoder mounted on the main motor shaft and incorporated
to detect and reject the desired packet.

We Claim:
1. A system for counting plurality of biscuits in a stack wherein said system
comprises a combination of optical sensors and proximity sensors to detect
biscuits on high speed moving conveyor of packing machine.
2. The system for counting plurality of biscuits in a stack as claimed in claim 1
wherein the speed of the conveyor is about 1- 30 m/min.
3. The system for counting plurality of biscuits in a stack as claimed in claim 1
wherein the sensors are placed across the motion of biscuit on infeed conveyor
of packaging machine to detect the biscuits in moving stack.
4. The system for counting plurality of biscuits in a stack as claimed in claim 1
wherein the optical sensors include emitter and receiver.
5. The system for counting plurality of biscuits in a stack as claimed in claim 1
wherein sinusoidal electrical waveform of different peak values are emitted
from the sensors which act as input for the processing system and processing
software converts the same in to a count.
6. . The system for counting plurality of biscuits in a stack as claimed in claim 1,
having a rejection station comprising pneumatic cylinder mechanism,
controlled by a PLC/Microprocessor and actuated on the basis of the go and
no go logic defined in the PLC/Microprocessor program.