WO1999066117A1

WO1999066117A1 - Computer monitored dye bath

Info

Publication number: WO1999066117A1
Application number: PCT/US1999/013950
Authority: WO
Inventors: Manpreet Arora; Thomas Koch
Original assignee: Crompton & Knowles Corporation
Priority date: 1998-06-19
Filing date: 1999-06-18
Publication date: 1999-12-23
Also published as: AU4580099A; WO1999066117A9

Abstract

A portable monitoring system having the ability to collect the real-time data from a dyebath machine with a high degree of accuracy. The system is divided into modules allowing the chemical sensing to be performed in close proximity to the dyebath while allowing the electronic analysis and control elements to be positioned remote from the dyebath. The chemical sensing equipment is connected to the dyebath by a circulation loop which circulates a sample flow from the dyebath past the sensing probes for analysis. The electronic analysis and control components are connected by fiber optical and electrical cables and can therefore be located remote from the dyebath. The spectrophotometer software has been programmed in a user-friendly way and can be operated by any personnel within a plant. The portable monitoring system automatically calculates calibration equations, optimizes the dyeing process, and archives all the dyeing data for later use.

Description

COMPUTER MONITORED DYE BATH

BACKGROUND OF THE INVENTION The present invention relates to apparatus for monitoring chemical properties in an industrial process. More specifically, the present invention relates to a portable monitoring system which is able to collect data from a dyebath in realtime.

The spectrophotometers used to give accurate and precise data during a real- time process have been very heavy and are not portable, thus making those systems unsuitable for use on plant scale dyeing machines in dyehouses. The software used to run the earlier systems are not very user-friendly and require certain skills to be able to run calibration and dyeing experiments.

The systems being used until now involve very heavy spectrophotometers and have to be close to the dyeing machines, thus subjecting them to extreme plant conditions. The systems have thus been limited to their use to laboratory studies only. The software used to run those systems is not very user-friendly and requires some expertise to run them.

The above problems are significant problems in the way of using such dyebath monitoring systems in a routine plant environment and by common plant workers.

The following references relate to monitoring of chemical composition in dying processes. Beck, K.R., Madderra, T.A., & Smith, C.B., "Real-Time Data Acquisition in Batch Dyeing," TCC, June 1991, pages 23-27. Smith, C.B., Lu, , "Improving Computer Control of Batch Dyeing Operations," ADR, September 1993. Jasper, W.J., Reddy, M.Y., "Real-Time System for Data Acquisition and Control of Batch Dyeing," Proceedings of Annual Textile, Fiber and Film Industry Technical Conference, IEEE, May 1994.

SUMMARY OF THE INVENTION The system is suitable for use on either a production or a laboratory machine. The system is user-friendly and provides easy-to-follow instructions to carry out the calibration of the dyes being used. The calibration equation is calculated automatically. The system then analyzes the absorbance data and converts it into concentration/exhaustion values for each dye in the system during the dyeing process. The system can be used to optimize the dyeing processes or to ensure repeatability and quality.

Accordingly, it is an object of the invention to provide a small-sized, portable spectrophotometer for use to collect the absorbance data reliably. A portable computer and portable wet chemistry module are utilized with the portable spectrophotometer so that analysis can be performed in a variety of locations. Fiber optic cables are utilized to connect the spectrophotometer with the spectro-probes, allowing for user defined separation between these components. The long fiber optic cables used to transmit light are protected with prestressed coiled stainless steel tubing. This helps the system to be installed safely in a plant environment. The system has provisions for automatic maintenance of the spectrophotometric probes, lint filters, and the pH probe. The system monitors the exhaustion profile of the dyes being used and thus can be used to optimize the dyeing cycle or to monitor the repeatability of established processes. The analysis process of the present invention can be superimposed on the previously established standard process to visualize if the current process follows the given protocol. The present invention can be used to provide real-time monitoring of dye concentration in an on-line dye bath. The system can also monitor the wash-off of reactive dyes and thus help to identify the optimum wash-off procedure and the final degree of fixation. The exhaustion profiles thus obtained can be used to select an optimum dyestuff combination that will help in getting level dyeings and minimal reruns.

The system is programmed in a user-friendly way so as to be able to run by any personnel in the plant. The system archives all the dyeing data for use at a later date. The present invention can monitor under an increased concentration range in by using a three/four channel spectrophotometer and one/two more flow through probe assemblies. The information about the rate of exhaustion of the dyes can be used to control the exhaustion profile of the dyes. This can be done by using a feedback control to dose the dyes and chemicals into the dyebath or by controlling the temperature of the dyebath. Various theoretical and empirical dyeing models can be used to achieve this.

IN THE DRAWING Figure 1 is a functional schematic block diagram illustrating the connection of the components of an exemplary embodiment of the system of the present invention implemented as a dyebath monitoring system.

DETAILED DESCRIPTION As illustrated in Figure 1, the system is divided into four modules: the electronics module 1, the wet-chemistry module 2, the computing module 3, and the power module 4. Electronics module 1 consists of spectrophotometer 10; light source 11; A/D board 12; pH transmitter 13, conductivity transmitter 14, and temperature transmitter 15; an electric actuator 16; and RS-232 port extender 17. Spectrophotometer 10 is connected to the computing module 3 via an appropriate interface, such as a PCMCIA card adapted for the portable computer illustrated in the exemplary embodiment of Figure 1. The communications port on the computing module 3 is connected to RS-232 port extender 17 in the electronics module 1.

A/D board 12 is connected to one of the ports on the RS-232 port extender 17. pH, conductivity, and the temperature data from the three transmitters 13, 14 and 15 in electronics module 1, the are transmitted to A/D board 12. A/D board 12 converts the analog signal to digital and sends the data over RS-232 port 17 to the computer 3. Fiber-optic cables 31 run out from the light source 11 to the spectrophotometer probes 21 in the wet-chemistry module 2 and to the references cell 32. Fiber-optic cables 33 from the other end of the spectrophotometer probe 21 send the light signal to the spectrophotometer 10.

Computing module 3 through A/D board 12 controls the electric actuator 16 which in turn controls the switching of three-way valves 22, 23 and 24 connected to the circulation loop in the wet-chemistry module 2. The wet-chemistry module 2 consists of the circulation tubing 34 coming out from the dyebath 35 and passing through the heat exchanger 36 to cool the dyebath solution before monitoring it. Dye solution then passes through one of the lint filters 25, the pH probe 26, conductivity probe 27, and spectrophotometer probe 21 before flowing back to the dyebath 35 through a heat exchanger 37 to heat the solution to the dyebath temperature. The temperature probe 38 is dipped directly into the dyebath 35, and data from pH probe 26, conductivity probe 27, and temperature probe 38 are sent to the respective transmitters 13, 14 and 15 in the electronics module 1. The wet- chemistry module 2 has two electronic multiport valves 28, which are used to calibrate the pH probe 26 and also to clean up the spectrophotometer probes 21 in- between operation. Computer 3, through RS-232 port 17 controls the valves 28 and automatically starts the clean-up process.

Lint filters 25 are installed in the circulation loop to allow for the cleaning of one of the filters 25 while the other is in use. Three-way valve 22/23 is used to change the flow of the dye solution from one loop to the other when a filter 25 is being cleaned.

The power module 4, consists of power supplies 41 and 42 which are used to power various electronic devices such as the pH 13, conductivity 14, and temperature 15 transmitters, light source 11, A/D board 12, and electric actuator 16. Computing module 3 controls and collects information from the spectrophotometer 10, pH transmitter 13, conductivity transmitter 14, and temperature transmitter 15. Computer 3 also controls the multiport valves 28 and the electric three-way valves 22, 23 and 24 connected to the dyebath circulation loop. Filter diverter valves 22 and 23 can optionally be manual valves controlled by an operator when the filters 25 are being cleaned.

One of the important aspects of the system of the present invention is that the system is divided into different modules which are easy to handle and can be located remote and/or separated from each other by using long lengths of wiring and fiber optic cables to connect them. Fiber-optic cables 31 and 33 are protected with a metal sheathing and can be laid anywhere applicable to the system installation, including a factory floor, connecting the spectrophotometer 10 remotely to the optical probes 21. The wet-chemistry module 2 can be closer to the dyebath reducing the size of the circulation loop 34. The wet chemistry module 2 is unaffected by extreme dyeing conditions. The computing module 3 and the electronics module 1 , which are more susceptible to the extreme conditions in the dyehouse can be located further away from the process machinery under ambient or controlled environmental conditions. The system is portable and can be hooked onto any dyeing machine at a suitable location. The setup of the system also allows for an intermediate clean-up of the spectrophotometer probes and the lint filters even during operation of the circulation loop 34 by diverting flow around the components being maintained. It can also allow for an intermediate calibration of pH probe 26.

Use of a miniaturized spectrophotometer 10 with protected fiber-optic cables 31 and 33 makes this system portable and suitable under extreme plant conditions. Separation of the wet parts 2 from the electronics 1 and 3 makes the data collection easier from a remote location and will further help to automate the dyeing process. This system can be used to collect real-time data on an in use production scale dying machine with a high degree of accuracy and is not limited only to a laboratory setup.

The system also has a built-in capability to do an automatic clean-up of the spectrophotometric probes 21 and the lint filters 25 and also to initiate a calibration of the pH probe 26. The system is very user friendly and can be operated by minimum computer expertise. The software can monitor the wash-off of reactive dyes. Thus their final degree of fixation can be ascertained. Provisions have been made to the software and the hardware to make the calibration semi or fully automatic.

Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirements of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.

Claims

We claim:

1. A monitoring system comprising: means for detecting physical characteristics of the liquid body to be monitored, said means for detecting optionally including one or more of a spectrophotometer; the light source; the A/D board; the pH, conductivity, and temperature transmitters; an electric actuator; and a means for connecting said transmitters to electronics module; means for transmitting output from the means for detecting to a means for calculating calibration equations based on an algorithm which computes a corrective output or logging historical output.

2. A positive feedback loop control system for a multiple feed liquid body comprising: means for monitoring a plurality of physical and chemical properties of said liquid body; means for calculating corrective values for said multiple feeds from said plurality of physical and chemical properties; means for controlling said feeds by changing the feeds based on the corrective values to modify the content of said liquid body to a predetermined desired property set.

3. A system for monitoring the characteristics of a liquid comprising: a sensor module; a circulation loop connecting said liquid and said sensor module; at least one sensor in said sensor module and operatively connected to said circulation loop for exposure to said liquid; an analysis module; a data loop operatively connecting said analysis module to said sensor module.

4. The system of Claim 3, said data loop comprising fiber optic cables and electric cables for transmission of optical and electrical information between said analysis module and said sensor module.

5. The system of Claim 3, wherein said data loop allows for remote cabling connection of said analysis module to said sensing module.

6. The system of Claim 3, wherein said sensor module includes a spectrophotometer probe.

7. The system of Claim 3, wherein said sensor module includes a pH probe.

8. The system of Claim 3, wherein said sensor module includes a temperature probe.

9. The system of Claim 3, wherein said analysis module includes a spectrophotometer; a plurality of instruments connected to said data loop for receiving sensor output; a computer for receiving data correlated to said sensor output and for calculating calibration equations based on an algorithm; an interface for connecting said instruments to said computer.