Title of Invention

AN IMPROVED COMPUTER CONTROLLED SELF INTELLIGENT JUICE FLOW STABILIZATION SYSTEM FOR SUGAR INDUSTRY

Abstract

Juice flow stabilization is one of the prerequisite needs for better process control in plantation white sugar manufacturing. Considering this Vasantdada Sugar Institute has designed and successfully developed a computer controlled self intelligent juice flow stabilization system for Sugar Industry. The system measures time between two consecutive tanks and level of juice in receiving tank and decides the appropriate rate of lifting juice by compensating the plus-minus juice quantity. This is achieved by a specially designed and developed an intelligent and dedicated software package. 7 MAR 2005

Full Text

ORIGINAL FORM 2 THE PATENTS ACT 1970 (39 OF 1970) COMPLETE SPECIFICATION (See section 10) AN IMPROVED COMPUTER CONTROLLED SELF INTELLIGENT JUICE FLOW STABILIZATION SYSTEM FOR SUGAR INDUSTRY VASANTADADA SUGAR INSTITUTE, a public trust registered under Bombay Public Trust Act-1960 having registered office at Manjari, Budruk Taluka Haveli District, Pune-412307 (India) The following specification ascertains the nature of the invention and the manner in which it is carried out. 7-3-2005 GRANTED This invention relates to an improved computer controlled self intelligent juice flow stabilization system for sugar industry. In plantation white sugar processing the constant juice flow is one of the basic needs to achieve better efficiency of clarification process. The constant juice flow is helpful to reduce variation in chemical doses, juice temperature vapour consumption at juice heater, mud level etc. However, this requirement in plantation white sugar industry cannot be fulfilled due to one or more of the following reasons: - Batch type weighing of raw juice. - Variation in raw juice % cane from 85 to 120 % on cane. - Variation in current cane crush rate ± 50 % of rated capacity. - Variation in filtrate flow. - Installation of higher juice capacity pumps to absorb the above variation. - Raw juice storage not preferred due to danger of microbial growth. - Variation in actual pump head of process as compared to pump design head. Due to abovementioned difficulties the constant juice flow cannot be achieved by sugar mills. Therefore great interest has been generated in developing an appropriate juice flow stabilization system obviating the above mentioned problems. The inventors at the Vasatdada Sugar Institute (VSI) have studied the work done by various workers on juice flow stabilization and designed, developed a computer controlled self intelligent system for juice flow stabilization. The system is much superior than the existing systems of juice flow stabilization. The overall system and the results are discussed here. In the prior art following techniques are used in juice flow stabilization. These techniques can be classified as manual control, instrument control system, use of mass flow meters etc. 1. Manually controlled systems: The manual control is based on one or more of the ways, by opening raw juice bypass valve as per crush rate, by controlling raw juice suction or delivery valve as per need. Using these techniques the juice flow variation could be reduced to some extent. However, these techniques suffer from following drawbacks: - Use of bypass valve necessitates recycle of juice. This leads to increased power consumption. - When juice level in storage tank is maximum, higher quantity of juice needs to be recycled. Some quantity of juice is also being recycled when juice level in storage tank is minimum. This leads to higher flow variation. - Generally juice bypass line is before juice heater i.e. at low head level and this makes control difficult. - Control of delivery valve increases the back pressure on pump which leads to mechanical troubles. - Control of suction valve is somewhat better as compared to bypass or delivery valve, but some times pump may be starved of juice. - Due to variable crush rate, variable positive head and human errors, the stabilized juice flow up to satisfaction is not possible by using all these manual system. 2. Auto controlled systems : Various firms have installed auto control systems for juice flow stabilization. Most of the auto controlled juice flow systems operate on one of the following principles. - Measurement of pressure of raw juice after pumping and then controlling either pump suction or delivery or bypass valve. - Measurement of raw juice pump power consumption and then controlling either pump suction or delivery or bypass valve as per need. - Measurement of level of raw juice receiving tanks, number of tanks/hr and juice pressure after raw juice pumping and then controlling delivery or bypass or suction valve of the raw juice pump. The inventors of the present invention have observed that the systems based on above techniques can achieve flow stabilization of the order ± 25% variation. However, these systems have their own limitations and drawbacks which can be summarized as: - At variable crush rate juice flow stabilization could not be achieved. - Flow stabilization accuracy is not up to the satisfaction. - Set points have to be changed from time to time. - Indirect juice flow stabilization i.e. juice flow meters have not incorporated in the system. - The factory staff is not attending maintenance problems. - Optimization of electrical power for juice pumping is not possible. 3. Mass flow meter The mass flow meter is not actually juice flow stabilization system. The aim of mass flow meter is better accuracy in juice weighing. But with the introduction of mass flow meters the problems due to batch weighing of raw juice are reduced. However, the juice variations due to other reasons such as variable crush rate, higher pump capacity, variation in filtrate flow, etc. could not be solved. In short mass flow meters are not useful as a juice flow stabilizer. The juice flow stabilization systems installed by Indian firms in the sugar industry have succeeded in reducing juice flow variation from ± 100 % to ± 20-30 % of rated flow. However, all these systems have their own limitations. It has been observed that most of the installations are out of the use in number of sugar mills within a short period. In the light of the abovementioned drawback in the prior art systems the inventors designed and developed a computer controlled self intelligent juice flow stabilization system for Indian sugar mills and have been published at Sugar Technologist Association of India (STAI), September 2000. The computer equipped with the software developed by the inventors provided an effective juice flow stabilization system. The juice extracted in the sugarcane milling system enters the system through a magnetic flow meter in the receiving where it is weighed in the weighing tank. The weighed juice is colleted in the storage tank, which is equipped with a level sensor. The juice from the storage tank is taken for further processing through a pump and another magnetic flow meter. Mixed filtrate in the further processing is recycled to the storage tank. The intelligent software programme takes in to consideration the level of the juice storage tank, the speed of the incoming juice in the receiving and the weighing tanks and accordingly operates the pump to keep the flow at optimum. The Computer controlled juice flow system described in the publication of STAI, September 2000 measures time between two consecutive tanks and level of juice in receiving tank and decides the appropriate rate of lifting juice by compensating the plus-minus juice quantity. The system runs the juice pump with appropriate speed. The juice flow rate is measured by the magnetic flow meter and communicated to the computer which adjusts the speed of the juice pump to keep the flow close to the expected flow rate. This is achieved by a specially designed and developed an intelligent and dedicated software package. The system is self-intelligent, in taking decision of control of the juice flow. The system keeps history of variables such as time, level and flow rate. The performance of the system is recorded in graphical form through out the working period. This system also had following drawbacks. 1. The magnetic flow meter is very costly. 2. The water addition increased the load on the boiler house requiring more energy in the form of steam. 3. The bypass valve increased the load on the pump thereby using additional electricity. 4. The suction line valve also increases the load on the pump set. In view of these drawbacks it was desirable to develop the improved juice flow control system where input magnetic flow meter, water addition, by¬pass and suction valve are removed. The main object of the present invention is therefore to provide an improved computer controlled self intelligent juice flow stabilization system for the sugar industries. Another object is to provide a system, which obviates the drawbacks of the systems described hereinbefore. Still another object is to provide a system, which will be energy efficient. Still another object is to provide a system based on computer control which will be self intelligent to consider various parameters like level in storage tank, rpm of pump, output juice flow variation and tank dumping time history and accordingly regulate the operation of the pump set to optimize the sugarcane juice flow. Still another object is to remove the need of costly equipment and make the system user friendly. The system working is explained as under. Fig.(l) shows the new computer controlled juice flow stabilisation system. To begin with, the serial port communication protocol is initialised for each sensor viz. flow meter (11), level sensor (5) and time sensor (10). The data from each sensor are given to the computer (9) through RS422 to RS232 converter and intelligent RS232 card. Fig. (2) shows the software flow chart of the system. There are three modes of operations : Manual, semi-auto and auto. In manual mode, the user sets the speed of AC drive (14) to a slightly higher side to avoid the overflow of juice storage tank. In this mode, total operation of the system is by-passed but all parameters are monitored and recorded in the database. In semi-auto mode, the user sets the flow rate of outgoing juice by making use of computer and the computer decides the speed of AC drive (14) required for maintaining the set flow rate. In this mode, all parameters from sensors are monitored. Here all automatic calculations of set point and subsequent routines are by-passed. The drawback of this mode is that the AC drive (14) may run empty due to manual fed set point. In auto mode, all parameters are monitored and taking into considerations the recorded dumping time of previous tanks and current juice level in the storage tank, required juice flow rate is calculated and accordingly the speed of AC drive (14) is set to maintain the juice flow rate constant. If the difference between calculated flow rate and set point is more, the increase or decrease of flow rate is gradually changed to avoid jerks in flow rate. All parameters are stored for future reference. All parameters and variation in flow rate are continuously displayed on computer monitor. The signals from sensors such as level sensor, tank counter and magnetic flow meter are digitised by the signal conditioning circuit and made available in the form of RS422. BRIEF DESCRIPTION OF THE DRAWINGS Fig-1 describes the schematic diagram of the juice flow stabilization system. Fig-2 shows the flowchart of software for the improved computer controlled self intelligent juice flow stabilization system for sugar industry. DETAILED DESCRIPTION OF THE INVENTION: Fig-(l) describes the new computer controlled juice flow stabilization system which comprises an inlet (1) for the juice opening in a receiving tank (2) opening in a weighing tank (3), a storage tank (4) equipped with a level sensor (5), a delivery pump (6), magnetic flow meter (11), a microcomputer (9), a time sensor (10). In a preferred embodiment of the present invention the receiving tank (2) opens in weighing tank (3) and weighing tank (3) opens in storage tank (4) through the outlet valves (12) and (13) respectively, the operations of which are synchronized mechanically to allow the desired quantity into the weighing tank (3) and storage tank (4). In another embodiment the storage tank (4) is provided with an inlet for mixed filtrate. In yet another embodiment the storage tank is provided with a pump controlled through AC drive (14) for transferring the juice from the storage tank (4) to the juice heater through magnetic flow meter (11) via outlet (8). In another embodiment the computer (9) is electronically connected to the level sensor (5), AC drive of the delivery pump (6), the time sensor (10) and magnetic flow meter (11) for transferring the juice from the storage tank (4) to the juice heater through magnetic flow meter (11) via outlet (8). In another embodiment the computer (9) is electronically connected to the level sensor (5), the controller of the delivery pump (6), the time sensor (10) and magnetic flow meter (11). In another embodiment the microcomputer is equipped with the software developed by the inventors of the present invention and owned by Vasantadada Sugar Institute, for which the copyright registration is pending with the Registrar of the copyright (Application No. 459/2001 CO(SW) dated 28th March 2002 and the flowchart of which is given in Fig.(2)). In a typical description of the working of the juice flow stabilization system provided by the present invention the juice extracted from sugar cane is received in the weighing tank (3) through the receiving tank (2) wherein it is weighed and the weighed juice is allowed to flow in the storage tank through synchronized value (13). Depending upon the time between two successive drops of the weighing tank and the level in the storage tank (4) as sensed by the level sensor (5), the computer decides the required set point of the output flow through the magnetic flow meter (11) and thereby controls the operation of the delivery pump (6) to allow the desired optimum flow of the juice to the heater through outlet (8). In yet another embodiment, the computer is equipped with the software to take into consideration various factors like change in tanks per hour, increase or decrease of left over juice level in storage tank, short stoppages of mills etc. to calculate the required variation in rpm and flow rate to absorb the changes and maintain smooth increase or decrease in flow rate as per need. In another feature of the present invention the mixed filtrate is obtained from vacuum filter unit in the further processing of the sugarcane juice. In yet another feature the receiving tank, the weighing tank, the storage tank and the connecting pipelines are made up of the conventional metals used in the industry. Table-1. Sr. No. Particulars With Stabi out Juice Flow isation System With Juice Flow Stabilisation System Mixed Juice Clear Juice Mixed Juice Clear Juice 1 Brix % 17.558 17.923 17.367 18.235 Purity 85.02 85.86 84.961 86.05 Rise In Purity 0.84 1.09 2 (ICUMSA) Colour at * 560nm at Sample pH 19258 2473 22136 2340 * 560nm at 7.00 pH 22261 2564 24252 2365 * 420nm at Sample pH 34520 10971 38198 7548 * 420nm at 7.00 pH 94127 22604 68695 14172 3 Standared Devation for ICUMSA Colour at * 560nm at Sample pH 4258 194 6260 199 * 560nm at 7.00 pH 3503 245 4861 200 * 420nm at Sample pH 6272 1001 9275 1156 * 420nm at 7.00 pH 21514 4990 20924 2760 4 % Colour removal from IV lixed Juice to Clear Juice * 560nm at Sample pH 87.16 89.42 * 560nm at 7.00 pH 88.48 90.25 * 420nm at Sample pH 68.22 80.23 * 420nm at 7.00 pH 75.98 79.37 5 % Turbidity * 560nm at Sample pH 72.99 2.73 62.93 2.73 * 560nm at 7.00 pH 58.87 2.39 48.38 2.32 * 420nm at Sample pH 94.41 5.47 81.46 6.81 * 420nm at 7.00 pH 74.12 6.05 56.12 6.89 j In yet another feature of the present invention, the AC drive of pump is connected to computer and the drive output is connected to the pump. The effect of flow variation on clear juice with and without the use of the juice flow control system is illustrated in Table (1). From Table-1 it is concluded that - International Commission for Union Method for Sugar Analysis (ICUMSA) Colour of clear juice improved by 200 ICUMSA unit at 560 nm and 800 ICUMSA unit at 420 nm. - Clear juice ICUMSA colour is reduced - Improvement in rise in purity from mixed juice to clear juice. - Increase in mud settling rate . Reduction in power consumption : Electrical power required to pump the raw juice is also found reduced from 1.35 to 1.17 Units per Juice tank due to controlled juice flow. This is one of the additional advantages of the system. WECLAIM: 1. A computer controlled juice flow stabilization system comprises a receiving tank (2), weighing tank (3), storage tank (4), synchronized valves (12) and (13), level sensor (5), flow meter (11) and delivery pump (6) wherein the juice extracted from sugarcane is received in the weighing tank (3) through the receiving tank (2) wherein it is weighed and the weighed juice is allowed to flow in the storage tank (4) through synchronized valve (13), depending upon the time between two successive drops of weighing tank (3) and the level in the storage tank (4) as sensed by the level sensor (5), the computer decides the required set point of the output flow through the magnetic flow meter (11) and thereby controls the operation of the delivery pump (6) to allow the desired optimum flow of the juice to the heater through outlet (8). 2. A system as claimed in claim 1 wherein the receiving and weighing tanks are synchronized mechanically to allow the desired quantity into the weighing tank 3. A system as claimed in claim 1 wherein the storage tank is provided with an inlet for mixed filtrate. 4. A system as claimed in claim 1 to 3 wherein the computer is electronically connected to the level sensor, the controller of the delivery pump, the time sensor and magnetic flow meter. 5. A computer controlled juice flow system as fully described hereinbefore (claim 1-4) with reference to Fig. 1. Dated this 10th day of August 2001.

Documents:

791-mum-2001-abstract(7-3-2005).doc

791-mum-2001-abstract(7-3-2005).pdf

791-mum-2001-cancelled pages(7-3-2005).pdf

791-mum-2001-claims(granted)-(7-3-2005).doc

791-mum-2001-claims(granted)-(7-3-2005).pdf

791-mum-2001-correspondence(1-3-2005).pdf

791-mum-2001-correspondence(ipo)-(28-9-2006).pdf

791-mum-2001-drawing(7-3-2005).pdf

791-mum-2001-form 1(28-6-2006).pdf

791-mum-2001-form 19(13-1-2004).pdf

791-mum-2001-form 2(granted)-(7-3-2005).doc

791-mum-2001-form 2(granted)-(7-3-2005).pdf

791-mum-2001-form 3(28-6-2006).pdf

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