Auto dosing and dispensing systems For Dye house

Auto Dosing & Dispensing System For Dye House Prepared By : Mazadul Hasan sheshir ID: 2010000400008 13th Batch (session 2009-2013) Department : Wet Processing Technology Email: mazadulhasan@yahoo.com Blog : www. Textilelab.blogspot.com (visit) Southeast University Department Of Textile Engineering I/A 251,252 Tejgaon Dhaka Bangladesh Prepared By : In addition to the control of dyeing machines, a fully-automatic control system performs various other functions, as summarised in. An alternative approach to totally automatic weighing is to use simple or paternoster storage systems with manual weighing in a down-draught booth, controlled by a check-weighing system. This is followed by dissolving or dispersing and distribution from dispense tanks that can be linked into the control system (section 3.12). Developments in control systems have centred around increases in the power of microprocessors with a reduction in their size and cost . The dyehouse manager can interrogate the control system from home using the Internet. Information from the system can be used to optimise the areas of: planning and scheduling, process control, selection of recipe and process, quality and production information. Systems can be operated from keypads or touch-screen colour displays and can include machine diagrams, on-line process diagrams, displays of future scheduling and various analytical information functions (such as efficiency and consumption analysis). Virtually any function can be automated at a cost, needless to say, but some of the control parameters that are available to assist in obtaining RFT processing are listed in. Automation commercially available systems. Dispensing and automated handling systems for dyes and chemicals have been reviewed and a tabular guide given of the functions available on commercially available systems for which contact details are given . The ColorService TRS automatic weighing and dissolving system for solid dye brands has been described. The main advantages include sealed, dry and safe storage of dyes, preventing moisture fluctuations commonly encountered with open containers, elimination of health hazards to operatives because of dust-free storage, weighing and dissolving conditions so that < 1 ppm dye dust is detectable in production areas . Control systems can be stand-alone or include colour physics capabilities and several options for the use of automation in both the laboratory and production were suggested . A typical control system is illustrated schematically in Figure 4.1 and details of the Process ITM (Datacolor International) system are given in. Automation As indicated in section 3.12, the dispensary is a major key to success in obtaining reproducibility of dyeing and has received a great deal of attention . Dispensing, dosing and metering of dyes and chemicals have been thoroughly reviewed recently , with discussion of all the elements involved in Major factors in achieving reproducibility in dyeing are the weighing, measuring and dispensing of dyes and chemicals. Sumner [43] identified inaccurate weighing of dyes and measuring of chemicals as the two most important causes of off- shade batches. The location, design, layout and equipping of the ‘drugroom’ or dispensary, therefore, are vital factors in the quality management of a dyeing operation. This facility also impacts on health and safety requirements, as discussed in section 2.1.1. Many advantages and savings can be gained by the selection of rationalised ranges of dyes, auxiliary products and chemicals, as discussed in section 5.8.1. In view of the demonstrated importance of these factors, it is surprising that they have been neglected in many dyehouses. Dye And Chemical Dispensing It is standard practice to isolate the dispensary from the main production area of the dyehouse to avoid contamination of work in progress. The removal of all dye handling from dyeing machine operatives, moving the dispensary into a dedicated area and ensuring that only suitably trained personnel work there, probably achieves the greatest single step in improving accuracy. A saving in labour costs follows but these actions are also essential on health and safety grounds. Early dyestores were primitive ‘kitchens’. Even when dyes and chemicals are dissolved or dispersed manually, it is advantageous to locate the dispensary on an upper mezzanine of a two- or three-tier dyehouse, so that dye/chemical solutions/ dispersions can be gravity-fed to the process equipment. Where it is not possible to site the dyestore on an upper floor because of building restrictions, mobile dispensing tanks can provide a first step towards centralising dye and chemical handling. Dispensing to processing equipment sited on the same level is possible but requires the use of pressure pumps to transfer solutions or dispersions and this complicates cleaning procedures . Dye And Chemical Dispensing In an ideal design, a bulk storage area on the ground floor holds unopened containers of dyes and auxiliaries. A lift is provided for transferring these to the higher level dispensary when needed. On this upper mezzanine, a dry room with suitable storage devices is available for products in immediate use. Another dry room, equipped with a laminar-flow or down-draught extraction booth, is used for weighing. It is preferable to convey product containers to this second room for weighing in turn directly from a delivery container into a clean, dry, stainless- steel bucket using a clean, dry scoop. A wet room is provided for dissolving or dispersing and dispensing from mechanically stirred mixing vessels. The floor in the dispensary should be chemically resistant and of sufficient weight- bearing capacity to allow for the traffic of heavy containers. Walls and floors should allow for easy and regular cleaning. Suitable storage for dyes ranges from simple shelving to paternoster devices. The wide variations that exist in container design and size, often influenced by the physical properties of solid or liquid brands of dyes and auxiliaries, complicate the design of storage systems. Dye And Chemical Dispensing The variability which can occur in the moisture content of disperse dyes caused by changes in ambient conditions has been studied and the influence that such changes have on the colour of wool dyed with acid dyes has been measured instrumentally . The simplest expedient is to keep containers tightly closed between weighings. Air-conditioning and ventilation should be considered in the dispensary, since recent work [38] indicates that this investment gives a short payback period through improved consistency in wool dyeing. Complete air changes should occur six times per hour, with simple ‘air-lock’ door systems (often photo-electrically controlled) under slightly negative pressure being provided at entrances to maintain the atmospheric conditions while preventing the escape of contamination. Extraction equipment with air-conditioning and ventilation in the dispensing area removes steam from mixing and dispensing tanks. Weighing of dyes, chemicals and auxiliaries is crucial. Repeatable and accurate weighing to within 1% of target is required. At least two balances are required, one to handle amounts in grams up to 1 kg and the other for 1 kg or more. To weigh small quantities for pastel dyeings and shading additions, dilute solutions of the dye can be used. The weighing operation raises serious concerns for health and safety since the disturbance of powders produces aerosols which can be inhaled by the weighing operative . Reactive dyes have been the main cause for concern Dye And Chemical Dispensing Engineering solutions are the preferred approach to this problem with the installation of weighing booths and extraction cabinets. The selection of suitable physical forms, such as liquids, grains or non-dusting powders, also alleviates the problem. ‘Space-suiting’ including nasal masks, goggles, gauntlets and overalls that must be regularly laundered are provided individually for each operative. Standard operating procedures should be established for dissolving or dispersing and dispensing dyes. The modern dispensary is equipped with stainless-steel dispensing tanks, these being either conical or cylindrical in shape, the number required for each dyeing machine depending on the process details. Such tanks are usually equipped with the facilities listed in. Dyes, chemicals and auxiliaries are gravity-fed to the dyeing machine through stainless-steel or glass tubes. When dispensing from the mezzanine level, sufficient time must be given at the appropriate phases of the dyeing routine to allow homogenisation of the liquors and travel to the dyeing machine. The increasing use of ultra-low liquor ratio (ULLR) dyeing machines and centralised dispensing emphasises the need for dyes and chemicals of adequate solubility or dispersibility and stability properties. Large weights of salt and alkali associated with the dyeing of cellulosics are added at the dyeing machine level. The packaging, storage and handling of dyes and chemicals have been reviewed . Dye And Chemical Dispensing [...].. .Auto Dosing System 1 All the chemicals required for dyeing operation are mixed in the dye bath automatically from auto dosing system” 2 It is an integrated system controlled by computer which involves all the calculation required for exact amount of chemicals needed for dyeing a particular recipe 3 No of tanks:- 17 Two large tanks (SILO) for Salt & Soda – Soda tank: 16... requirements 1 Automatic level control for filling 2 Steam heating and temperature control 3 Stirring device of the correct design 4 Gravity feed to the dyeing machine 5 Drain to waste for cleaning 6 Rinse ring, usually a perforated pipe in the top of the vessel 7 Hot and cold water, often supplied through the rinse ring SAILO DOS Use for store dry salt and soda at large volume Dyestuff Dispensing Dyestuff... supplied through the rinse ring SAILO DOS Use for store dry salt and soda at large volume Dyestuff Dispensing Dyestuff Rack Dyestuff Rack Salt Dispensing Dyestuff Dispensing Salt Sailo Dispensing Liquid Chemical Dispensing Dyestuff Dispensing Dyestuff Dispensing Auxiliary Dispensing ... particular recipe 3 No of tanks:- 17 Two large tanks (SILO) for Salt & Soda – Soda tank: 16 ton Salt tank: 31 ton Salt & Soda are made solution in the mixing tanks before storing into Silos There are 3 mixing tanks-Common mixing tank for both soda & salt – 1000 li -Salt mixing tank – 1000 lit – 1.5 lit water per kg of salt -Soda mixing tank – 1000 lit – 2.5 lit water per kg of soda Tanks →Chemical . packaging, storage and handling of dyes and chemicals have been reviewed . Dye And Chemical Dispensing