GB2338658A - Computer-controlled apparatus for the manufacture and distribution of slurry - Google Patents

Abstract

The apparatus comprises a powder silo 1 (Fig 1) which feeds a slurry manufacturing pipe 16 via an intermediate storage bin 6 provided with load cells 9 for measuring the quantity of powder removed from the bin. The slurry pipe 16 (Fig 2) includes a perforated ring 34 and perforated vertical pipe 35 for injecting water onto downwardly-flowing powder deflected onto the pipe wall by cone 33 at the top of pipe 35. The slurry is then distributed via valves 26 (Fig 1) to wet processing machines M1-M6 for dyeing textile and leather.

Description

= a 23386DU 1 1 System for the Manufacture and Distribution of a Slurry 3

4 5 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 The present invention relates to a method and apparatus for the manufacture and distribution of slurry for use in wet processing machines, particularly those in the textile and leather dyeing industries.

For many years electrolyte slurries having high concentrations of electrolyte have been used in textile and leather dyeing processes to migrate the dyestuff from an aqueous dyebath to the substrate. As a result, the handling of large volumes of auxiliary powdered chemicals such as Pure Dried Vacuum Salt (Sodium Chloride) and Anhydrous Glauber's Salt (Sodium Sulphate) has been required.

In certain types of dyeing, a saturated solution of common salt (brine) can be used, but in other dyeing mechanisms the amount of water carrying the salt leads to an effective overfilling of the machine to achieve the required salt concentration in the dyebath. Saturated solutions of Glauber's Salt have not been used since the solution requires trace heating of the pipe-work to avoid crystallisation and pipework blockages.

2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 36 The conventional method by which these auxiliary powders are added to the dyebath at present is a manual method, in which an operator empties 25kg plastic sacks of the product into the dyebath. This method is laborious, since in some cases it may be necessary to add as much as 800kg of product at a time. The manual method carries with it several inherent risks. For instance, there can be errors in the number of bags added, pipe-work blockages can occur in the machinery if the powder is added too quickly, or there may be a risk of physical injury to the operator.

It is an object of the present invention to overcome the aforementioned disadvantages and to provide a method and apparatus which can automatically manufacture a slurry in which solid particles are suspended in a liquid (as opposed to being dissolved in a solution) on a continuous basis, and can distribute this slurry by a pump and/or distribution line to a wet processing machine.

According to a first aspect of the present invention, there is provided an apparatus for the manufacture and distribution of slurry, comprising: a storage container for the storage of a powder for use in the manufacture of a slurry; an intermediate container provided with measurement means for measuring the quantity of powder removed from the intermediate container; conveying means for the conveying of said powder from said storage container to said intermediate container; a slurry pipe; powder discharge means for the conveying of said powder from said intermediate container to said slurry pipe; 3 1 means for injecting water to said slurry pipe, the 2 water and powder forming a slurry; and 3 distribution means for the distribution of said 4 slurry from said slurry pipe.

6 7 8 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Preferably the slurry pipe comprises a vertical truncated cone having a downwardly decreasing diameter. Preferably the water injection means comprises a perforated pipe arranged substantially axially within the truncated cone. Preferably the slurry pipe further comprises a powder deflector arranged at the upper end of the perforated pipe. Preferably the powder deflector has a conical shape. Preferably the slurry pipe further comprises a perforated rinse ring arranged at the upper end of the truncated cone adapted to supply rinse water to the internal surface of the truncated cone.

Preferably, said measurement means comprises load cells for registering the mass of powder in said intermediate container.

Preferably, the apparatus further comprises a container provided with agitation means for mixing said slurry, a distribution pump and outlet means for the distribution of said slurry. Preferably, said agitation means is in the form of an electrical mixer.

Preferably, said distribution pump is a glandless pump and is highly resistant to abrasion.

Preferably, said outlet means is in the form of a distribution pipe, said distribution pipe being provided with destination valve means for the control of the slurry distribution, most preferably in the form of a plurality of distribution valves.

i 4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 According t-: second aspect of the present invention, there is pr--- ded a computer control system for the control of a. slurry manufacture and distribution process, comprising: data input means adapted to permit the input of predetermined slurry recipe data and slurry requirements; data storage means for storing said predetermined slurry recipe data; electronic calculation means adapted to calculate required amounts of water and powder based on said recipe data; valve control means for controlling the operation of a valve to permit the flow of powder from a powder storage container; load registering means for measuring a predetermined mass of powder according to said recipe data; water metering control means for metering a predetermined volume of powder according to said recipe data; a slurry pipe for mixing said powder and water to form a slurry; and distribution control means for controlling the distribution of said slurry according to the recipe data.

Preferably the computer control system further comprises checking means for checking the operation of components used in the slurry manufacture and distribution process, adapted to send an alarm signal and stop automatic operation of the process if a fault in a component is found. In particular the control system may include a valve checking means for checking the functioning of the distribution valves, the valve checking means comprising pulse signal generation means 1 2 3 4 5 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 adapted to send an electronic signal to a distribution valve to open said valve and switch means adapted to monitor whether said valve opened in response to the electronic signal.

Preferably the computer control system is used in conjunction with apparatus according to the first aspect of the invention.

Preferably, said load registering means is the form of load cells connected to said computer control system.

Preferably, said water metering control means comprises a flow meter and one or more automatic water valves controlled by said computer control system.

The system may further include display means in the form of a visual display unit to display information on the operation of the system.

The system may further include an alarm means in the form of an audible or visual signal activated by said computer control means.

According to a third aspect of the present invention, there is provided a method for manufacturing and distributing slurry, comprising the steps of: conveying a chemical powder from an intermediate container to a slurry pipe while measuring the weight of powder in the container, until a predetermined weight of powder has been conveyed from the container; injecting a predetermined volume of liquid into said slurry pipe and thereby blending said powder and said liquid to create a slurry; and distributing said slurry from said slurry pipe via a pump and outlet means.

6 1 2 3 4 6 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26 27 28 29 30 31 32 33 34 35 36 1 1 Preferably the method uses an apparatus according to the first aspect or a system according to a second aspect of the invention.

The system is computer controlled and is capable of functioning either as a stand-alone where the operator selects the amount of product and the machine requiring the addition from a computer screen, or the system is connected to the dyehouse computer network and can read figures of product weights and machines directly from the database.

When functioning as a stand-alone system, the system can execute the addition and store the actual values of product and water dispensed for stock control and other requirements. When connected to the dyehouse network, the product weight and machine figures are generated by a third party recipe management system which automatically calculates all chemical amounts in the recipe dependent on the weight of the dyelot. In this mode, the presence of an operator is not required and the addition is made automatically when the machine control system makes an automatic request via the computer network.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying figures, where:

Fig. 1 is a schematic view of a slurry manufacturing and dispensing system according to the invention; Fig. 2 is a transverse sectional view through a slurry manufacturing pipe of the system of Fig. 1; Fig. 3 is a flow chart showing the pre-dispense system 7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 checks undertaken by a slurry manufacturing and dispensing system according to the invention; and Fig. 4 is a flow chart showing the control mechanisms of a slurry manufacturing and dispensing system according to the invention.

The present invention is made up from a number of steps which use various components. The first step in the system is the storage of the powdered chemical. Each customer has a particular storage facility dependent on the quantities of electrolyte they use. Large users predominantly use a silo 1 where 20-25 tonnes of the powdered chemical will be stored, while smaller users commonly use 1 tonne Flexible Intermediate Bulk Containers (FIBCs).

From the base of the silo 1, the powdered product passes through a manual slide valve 2 and is conveyed by a flexible screw conveyor 4 and drive motor 5 to be deposited in a high level intermediate storage bin 6. The base of the silo 1 also contains an emergency switch 3, which prevents the conveyor 4 from operating should the powder level in the silo 1 drop below an arbitrary level.

The storage bin 6 contains an anti-peaking device 7 to prevent peaking of the powder in the bin 6, and an emergency switch 8 which prevents the conveyor 4 from operating should the level of bin 6 rise above an arbitrary level. In addition, the bin 6 also features a pair of antibridging devices 10, and is mounted on load cells 9 to register the amount of product contained therein. The control system (not shown) uses the input signal from the load cells 9 to operate a loss in weight system when the slurry is produced.

8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 This system is also used to re-charge the bin 6 after use.

Located at the base of the storage bin 6 is a slide valve 11 for manual isolation of the bin 6, should it be required. A loss in weight drive motor 12 and conveyor 13 then transport the powdered chemical to a slurry manufacturing pipe 16 at the required feed rate. The feed rate is monitored by the control system and controlled by way of an automatic isolation valve 14.

The slurry manufacturing pipe 16 is specifically designed so as to introduce water in such a way that the powder is forced to mix and produce slurry at the correct concentration. The powder is introduced via a discharge tube 41 into the pipe 16. Discharge tube 41 has an anti- dusting shroud 32 to prevent powder escaping from the manufacturing pipe 16. Within pipe 16 is a perforated vertical pipe 35 which forces water injection into the falling powder. The vertical pipe 35 features a conical top 33 to deflect powder to the internal wall of the pipe 16. Furthermore, a perforated rinse ring 34 allows water to slide down the internal surface of the pipe 16.

The concentration in the manufacturing pipe 16 is monitored by a water flow meter 18 and a temperature probe 20, and regulated by an automatic water inlet valve 19. In addition, manual balancing valves 36 are provided to ena ble intensive mixing, should it be required.

The slurry produced in pipe 16 falls into the small sump of a slurry manufacturing tank 15 where it is continuously stirred by an electrical mixer 17 and monitored by tank level sensors 21.

9 1 2 3 4 5 6 7 8 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Located at the base of the tank 15 is an outlet pipe 28 connected to the suction side of a distribution pump 22. The distribution pump 22 used is a glandless pump manufactured from a highly abrasion-resistant material. The pump 22 conveys the slurry into a ill nominal bore plastic distribution pipe 28 which is monitored by a pressure gauge 23. The distribution pipe is fitted with automatic three-way Tport diverter valves 24 containing microswitch assemblies 25 which are connected to the control system. After passing through the diverter valves 24, further distribution pipes 29,30,31 convey the slurry through automatic three-way T-port machine destination valves 26 to the required machines M1-M6. The destination valves 26 for each machine M1-M6 are controlled by the computer system.

Once the correct amount of product has been dispensed by the loss in weight feeder 13, chase water metered by the control system is introduced via the pump 22 into the distribution pipe 28. Sufficient chase waters are fed into the distribution pipe 28 to permit all slurry to be delivered to the processing machines M1-M6. This clean water is held in the distribution pipe 28 to act as a,lubricant" for the inside pipe wall for the next dispense. This also permits the absolute minimum of water to be added to the processing machines M1-M6.

When the subsequent slurry distribution is begun, the lubricating chase water already in the distribution pipes 29, 30, and 31 is emptied via line dump valves 27. By way of flow meters 50, the computer system senses when the lubricating water has all been drained, and then closes the line dump valves 27 and distributes the ensuing slurry through the machines M1- M6. Once the correct amount of product has been dispensed, more clean chase water is metered into the pipes for 1 2 3 4 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 lubrication of the next slurry batch, and the process is then repeated.

The computer control system is responsible for all control aspects of the system and, in addition, provides information on product usage by time and machine. Thus, it can pre-warn of recharge requirements at a silo 1 by triggering an audible or visible alarm. It can monitor the performance of the pump 22, using stroke counting to monitor diaphragm life within the pump 22. The computer control system may be linked to a terminal and monitor, on which it can display information on the operation of the system. The recipe data can be input from a remote computer networked to the computer control system, for example by reading the recipe mix data from a database, or it can be input manually by an operator who reads the mix requirements from a batch card.

The computer control system monitors the mixing process in real time and controls the opening and closing of valves to allow the powder to enter from the appropriate silo, to measure the weight of powder introduced via the intermediate storage bin, to control the addition of water to the slurry, and to deliver the slurry mixture to the appropriate processing machine. The computer control system calculates electronically the required amounts of water and powder based on the recipe data and the target volume of slurry. It can also control when and how quickly the components are mixed, and at what rate they are fed. It can monitor the state of the silos, and can send warning messages, e.g. by e-mail, when a silo is nearly empty and needs fresh powder to be ordered.

The invention may be better understood by reference to 1 2 3 4 6 7 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 the flow diagrams of Figs. 3 and 4. Fig. 3 shows the pre-dispense checks which are undertaken by the software controlling the system before the components of the slurry are dispensed 101. The dispensing procedure may be initiated by an external command via a computer network, which reads the recipe from a dyehouse database 102 and sends a call for the 8 appropriate amount of salt, or may be initiated manually by input from a keyboard 103, allowing the operator to choose a particular recipe. Whichever way the procedure is initiated, the job is placed in a queue 104 if another job is already in progress. The system then carries out a number of pre-checks 105. At each stage, if the check does not indicate that the check is passed, an alarm signal 150 is sent and the dispensing procedure is prevented from continuing 151, until the problem has been dealt with and corrected.

The electrical power supply 106, the response of the programmable logic controller (PLC) 107, the load cells 108, the status of the emergency stop control 109 and the level of compressed air ill, used for running the variable speed pump 22, are all checked. The emergency stop control is reset 110 if necessary. If the system has been operated in manual mode 112, then an alarm signal will be generated and the control system will not proceed until the operator has switched the system to automatic mode'113 by means of a key switch.

The amount of salt in the storage bin 6 is checked 114 using the load cells 9, and the bin is refilled 116 from the silo 1 if necessary. If the silo 1 is empty 115 the alarm 150 is activated. The level of salt in the storage bin is checked 117 by means of a powder level switch at the bottom of the bin, to ensure that there has been no bridging of the salt which would 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 36 interfere with the smooth delivery of the salt. if necessary the anti- bridging devices 10 are operated 118. These may include the injection of compressed air or nitrogen and/or vibration of mechanical fingers which induce flow of the powder through the bin.

The level in the distribution pipe 28 is checked 119 and refilled if required 120. If the slurry tank is not empty 121 before dispensing, then the contents are pumped to a drain 122.

The distribution ' line valves are checked 123, and three pulses are applied to free the valves if necessary 124. Because the system starts to make the slurry some time (typically a minute or so) before opening the distribution valves, it is essential to ensure that the valves are functioning properly before starting to make the slurry. A pulse signal is sent to open the valve, and feedback from the corresponding microswitch is used to determine whether the valve opened or not.

The water temperature is checked 125 and heated 126. A signal is then sent to the dispensing control that the system is ready for dispense 127.

Fig. 4 shows the control system for controlling the dispensing process, once the signal has been received that the system is ready for dispense 127. Any malfunctioning or non-passed check results in activation of the alarm 250, the aborting of the dispensing procedure, 251 and the storage of data relating to the aborted procedure to a system log 252.

The slurry water valve 19 is opened 200 and the flow rate checked 201 by means of water flow meter 18. The powder feeder conveyor 13 delivers powder 202 from the 13 1 2 3 4 5 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 bin 6 to the slurry manufacturing pipe 16, the mixer 17 mixes the resulting slurry 204 and the distribution pump 22 delivers the slurry 206. At each stage feedback checks are carried out 203, 205, 207 and more water is injected via the slurrywater valve if necessary 208. A destination valve 24, 26 is opened to deliver the slurry to the appropriate machine M1 to M6 209 while feedback is checked 210.

The system monitors the loss in weight rate 211 at the_ salt bin 6 and the communication link to the load cells 212. The level of salt in the storage bin is checked 213, to ensure that there has been no bridging of the salt which effects the smooth delivery of the salt. if necessary the anti-bridging devices 10 are operated 214. The water temperature is checked 215.

If the emergency stop control is operated 216, if the air pressure in the system is detected as being below a threshold value 218, if there is a power failure 219 or if there is a communications failure with the PLC 220, then an alarm signal is generated, but the dispensing procedure is not completely aborted. Instead a special abort procedure 217 is followed, in which the system records the status of the process at the time of abortion, and when the fault is corrected the system initiates an automatic recovery 221 to the status when the process was interrupted, and then continues with the dispensing process until the target weight is achieved 222. The dispensing process is then complete 223, and the data recorded by the control system during the process is written to a log 224.

These and other modifications and improvements can be incorporated without departing from the scope of the invention.

14

Claims (21)

1 CLAIMS:

2

3 1.

4 6 7 8 9 11 12 13 14 is 16 17 18 19 20 21 22 2.

23 24 25 26 3.

27 28 29 30. 31 32 33 34 36 An apparatus for the manufacture and distribution of slurry, comprising: a storage container for the storage of a powder for use in the manufacture of a slurry; an intermediate container provided with measurement means for measuring the quantity of powder removed from the intermediate container; conveying means for the conveying of said powder from said storage container to said intermediate container; a slurry pipe; powder discharge means for the conveying of said powder from said intermediate container to said slurry pipe; means for injecting water to said slurry pipe, the water and powder forming a slurry; and distribution means for the distribution of said slurry from said slurry pipe.

An apparatus according to Claim 1, wherein the slurry pipe comprises a vertical truncated cone having a downwardly decreasing diameter.

An apparatus according to Claim 2, wherein the water injection means comprises a perforated pipe arranged substantially axially within the truncated cone.

4. An apparatus according to Claim 3, wherein the slurry pipe further comprises a powder deflector arranged at the upper end of the perforated pipe.

An apparatus according to Claim 4, wherein the powder deflector has a conical shape.

1 2 3 4

5

6

7 8 9 10 11 12 13 14 is 16 17 18 19 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 6. An apparatus according to any of Claims 2 to 5, wherein the slurry pipe further comprises a perforated rinse ring arranged at the upper end of the truncated cone adapted to supply rinse water to the internal surface of the truncated cone.

An apparatus according to any preceding claim, wherein said measurement means comprises load cells for registering the mass of powder in said intermediate container.

8. An apparatus according to any preceding claim, wherein the apparatus further comprises a container provided with agitation means for mixing said slurry, a distribution pump and outlet means for the distribution of said slurry.

9. An apparatus according to Claim 8, wherein said agitation means is in the form of an electrical mixer.

2,0. An apparatus according to either Claim 8 or Claim 9, wherein said distribution pump is a glandless pump.

An apparatus according to any of Claims 8 to 10, wherein said outlet means is in the form of a distribution pipe, said distribution pipe being provided with destination valve means for the control of the slurry distribution.

12. An apparatus according to Claim 11, wherein said destination valve means is in the form of a plurality of distribution valves.

13.

A computer control system for the control of a 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 1 slurry manufacture and distribution process, comprising: data input means adapted to permit the input of predetermined slurry recipe data and slurry requirements; data storage means for storing said predetermined slurry recipe data; electronic calculation means adapted to calculate required amounts of water and powder based on said recipe data; valve control means for controlling the operation of a valve to permit the flow of powder from a powder storage container; load registering means for measuring a predetermined mass of powder according to said recipe data; water metering control means for metering a predetermined volume of powder according to said recipe data; a slurry pipe for mixing said powder and water to form a slurry; and distribution control means for controlling the distribution of said slurry according to the recipe data.

14. A computer control system according to Claim 13, further comprising valve checking means for checking the functioning of the distribution valves, the valve checking means comprising pulse signal generation means adapted to send an electronic signal to a distribution valve to open said valve and switch means adapted to monitor whether said valve opened in response to the electronic signal.

15. A computer control system according to either 17 11 12 13 14 is

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 1 Claim 13 or Claim 14, wherein said load 2 registering means is in the form of load cells 3 connected to said computer control system.

4 16. A computer control system according to any of 6 Claims 13 to 15, wherein said water metering 7 control means comprises a flow meter and one or 8 more automatic water valves controlled by said 9 computer control system.

17. A computer control system according to any of Claims 13 to 16, wherein said system further comprises a visual display unit.

18. A computer control system according to any of Claims 13 to 17, wherein said system further comprises an audible or visual alarm signal activated by said computer control system.

19. An apparatus according to any of Claims 1 to 12, further comprising a computer control system according to any of Claims 13 to 18.

20. A method for manufacturing and distributing slurry, comprising the steps of: conveying a chemical powder from an intermediate container to a slurry pipe while measuring the weight of powder in the container, until a predetermined weight of powder has been conveyed from the container; injecting a predetermined volume of liquid into said slurry pipe and thereby blending said powder and said liquid to create a slurry; and distributing said slurry from said slurry pipe via a pump and outlet means.

18 1

21. A method according to Claim 20, wherein the method 2 uses an apparatus according to any of Claims 1 to 3 12 and 19.