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Contenu archivé le 2022-12-27

AIR CURTAINS ON TEXTILE STENTERS

Objectif

To demonstrate that air curtains fitted to the fabric slots of a textile stenter will effectively seal the slots against passage of hot air and thereby save energy. At present, machine operators are obliged to use higher air exhaust rates and therefore more energy than strictly required by the process to help prevent the escape of stenter fumes via the fabric slots into the working environment. An annual energy saving of 30 TOE (30%) of the conventional consumption is to be expected at 'project level'.
A. FUME ABATEMENT
Stenter runs were too short for steady states to be established in the workroom atmosphere. Measurements in the vicinity of the fabric slots showed that air curtains could reduce fume concentrations to around 14% of the original values and impurity fluxes to 2% depending on operating conditions.
B. ENERGY SAVINGS
From November 1983 to October 1984 inclusive, 633 suitable job sheets have been analysed (60% of one year total production). These were with air curtains out of use and with exhaust rates set according to the original practice. From a knowledge of jobs to be processed, the stenter operators were provided with a list of optimum exhaust settings and instructed to apply them as far as possible and to use the air curtains. Though a recurrent valve problem did not allow the machine operators to respect the correct procedures, the average energy saving, over 18 stenter jobs, was 28,6%, achieved by reduction of exhaust rates and prevention of fabric slot leakage. Extrapolating the results to one year of jobs, and allowing weightings by process type, 24% energy equivalent to 997 gross GJ/year of natural gas would have been saved.
C. ECONOMICS OF THE SYSTEM AND POTENTIAL FOR REPLICATION
At project level, the payback time attached to the overcosts of the first realization is about 6 years, which evidently is not attractive. This was because the demonstration stenter had a relatively low level of use during the project. On machines with typical levels of use favourable payback times of 2.7 years and less should be achievable.
The licensor (The British Technology Group, 101, Newington Causeway, London SE1 6BU, Tel : 01-403-6666; Fax : 01-403-7486: Telex : 894397.
Contact : Mr Barry Hill) is seeking further licensees for textile and other applications e.g. in food, plastics. sheet metal lindustries.
The installation is essentially a double air-curtain arrangement on each side of the fabric and stenter chain. The inner curtain (nearest the stenter ) seals the fabric slot and its effectiveness is determined by a variable damper on the fan supplying ambient air to it. The outer curtain helps define a zone from which its own air supply is derived, by means of a fixed speed fan. The negative pressure in this zone enables the arrangement to swamp the variations in stenter pressure and to handle considerable non-uniformity of velocity - pressure along the length of fabric slot. Also, it collects all stenter air and fumes which may have leaked through the inner curtain. Automatic control of fumes abatement is achieved by inner curtain damper movement in relation to stenter, inner and outer curtain temperatures. Because conditions above and below the fabric will not, in general, be identical, the air curtains above and below are controlled independently. The two-bay stenter used for the project is manufactured by Artos - now part of Deutsche Babcock Textilmaschinen. The types of fabric and process are various. The processes considered for the project are drying, heat setting (alone and in combination in a single pass), and beaming. The maximum thermal demand by the stenter installation including thermal fluid heater is 723 KW and the gross energy consumption is estimated at 110 TOE/year. The equipment and the system to perform measurements have been used for a statistical description of the performances of the plant before and after innovations.
The measurements carried out on the plant aimed to determine, under any set of running conditions, the fume abatement characteristics of the air curtains and the energy savings due to the optimisation of stenter exhaust rates. As part of this work balances were measured/calculated of energy, airflow and volatiles from the fabric.

Appel à propositions

Data not available

Régime de financement

DEM - Demonstration contracts

Coordinateur

Shirley Institute
Contribution de l’UE
Aucune donnée
Adresse
Wilmslow Road Didsbury
M20 8RX Manchester
Royaume-Uni

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Coût total
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