GB1583199A

GB1583199A - Cloth drying apparatus

Info

Publication number: GB1583199A
Application number: GB5014077A
Authority: GB
Original assignee: E Gordon Whiteley Ltd
Current assignee: E Gordon Whiteley Ltd
Priority date: 1977-12-01
Filing date: 1977-12-01
Publication date: 1981-01-21
Also published as: AU4207678A; ES471560A1; DE2829092A1; NZ189064A; AU525779B2; FR2410800A1

Description

(54) IMPROVEMENTS IN CLOTH DRYING APPARATUS (71) We, E. GORDON WHITELEY LIMITED, of Beech Works, Morley, Leeds LS27 ONL, a British Company, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: When cloth is dried by treatment of cloth with hot air in a stenter, which holds the cloth to width on passage through the apparatus, or in a drier which does not hold the cloth to width, a problem arises in disposing of harmful fume arising from the presence of oil or dyestuff carrier in the cloth. The fume is manifested as a blue smoke and the operatives must be protected from it. Also environmental regulations prohibit discharge of the fume into the atmosphere.

With a view to eradicating such fume, the invention provides a cloth drying apparatus, comprising a drying chamber, means for advancing cloth to be dried through the drying chamber and, within the drying chamber, a circulating fan for circulating air in the drying chamber, nozzles for discharging air circulated by the fan onto the cloth, a burner for burning polluted air which has passed through the cloth, an air inlet for supplying sufficient fresh atmospheric air to the burner to maintain combustion, another fan arranged to feed the polluted air to the burner, a heat exchanger for receiving exhaust gas from the burner and wherein the exhaust gas exchanges heat with cooler air circulating in the drying chamber, means for returning the bulk of the cooled exhaust gas from the heat exchanger to the circulating fan, and an outlet for discharging to atmosphere the remainder of the cooled exhaust gas.

The burner thus serves not only to heat the air circulating in the drying chamber but also to burn and clean the polluted air by burning the fume. It is accordingly legitimate to discharge to atmosphere part of the exhaust gas after it has given up heat in the heat exchanger.

Preferably the burner is a gas burner of the kind supplied by Dunlop Ltd. as the Thermimax burner. This burner includes two plates joined by a series of tubes forming holes for the passage of combustion air. North Sea, coal or other gas is supplied to the outlet of each tube through an annular channel surrounding the outlet.

Radial drillings for the outlet of gas are also formed in the periphery of the plate assembly. In operation the flames from the individual tubes combine to form a central flame surrounded by a ring of flame produced by combustion of the gas emerging from the radial drillings.

One embodiment of stenter in accordance with the invention will now be described in more detail, by way of example; with reference to the accompanying drawings, in which Figure 1 is a plan view; Figure 2 is a section on the line II-II in Figure 1 on a larger scale; Figure 3 is a section on the line III-III in Figure 2; Figure 4 is a scrap part-sectional view showing the crown of the burner; Figure 5 is a plan view, partly broken away, showing part of the mechanism in Figure 2; and Figure 6 is a flow diagram.

The stenter 10 shown in the drawings include a series of enclosed drying chambers 11, through which a web of cloth 12 to be dried is advanced in succession by stenter chains (not shown) which engage the edges of the web in the conventional manner.

Each drying chamber 11 contains a circulating fan 13, which circulates air through the chamber and discharges it onto the upper and lower surfaces of the cloth through nozzles 14 from top and bottom pressure ducts 15, 16 as most clearly shown in Figure 2. The fan 13 is driven by an electric motor 23 (Figure 2) through a belt drive 24.

As best shown in Figures 3 and 5, a burner and heat exchanger system is provided at each side of each drying chamber 11. Each system includes a Thermimax burner 17, to which part of the polluted circulating through the chamber and also fresh air from an inlet 18 is fed by a centrifugal fan 19, driven by an electric motor 20 through a belt drive 21. The remainder of the circulating air returns to the circulating fan 13 through a filter. One of these filters is indicated at 22 in Figure 3, the remaining filters being omitted from the drawings for clarity.

Each burner 17 receives North Sea, coal or other gas through an inlet pipe 25 and includes a hood 26 (Figure 4), which includes tubes 27 for the passage of combustion air as indicated by the arrows A and passages 28, surrounding the tubes 27, through which gas flows as indicated by the arrows B. In operation flames from the individual tubes 27 combine to form a central flame surrounded by a ring of flame produced by combustion of gas flowing through radial holes 29 in the crown.

The clean exhaust gas from each burner 17 passes to a heat exchanger 30, where it gives up heat to the circulating air. The bulk of the exhaust gas is returned through exit slots 31 from the heat exchanger to the circulating fan 13 and the rest is discharged to atmosphere as a fume-free product through an outlet 32.

When the stenter is being used to dry cloth and air is circulated in each drying chamber at a rate of approximately 25000 cft/min it is necessary to maintain the circulating fans 13 in operation. When, however, the stenter is used for heat setting of cloth a slower circulation of air is required, e.g. 12000 cft/min, and the fans 13 are then switched to slow speed.

In the flow diagram shown in Figure 6, the portion 33 of the airflow represents polluted air which has been cooled to a temperature of, say, 1700C by contact with the cloth. The portion 34 represents clean exhaust gas from the burner 17 at a temperature of, say, 450"C. The portion 35 represents circulating air heated in the heat exchanger 30 to, say, 230"C. The portion 36 represents cooled exhaust gas returned from the heat exchanger 30 to the circulating fan 13.

WHAT WE CLAIM IS: 1. A cloth drying apparatus, comprising a drying chamber, mcans for advancing cloth to be dried through the drying chamber and, within the drying chamber, a circulating fan for circulating air in the drying chamber, nozzles for discharging air circulated by the fan onto the cloth, a burner for burning polluted air which has passed through the cloth, an air inlet for supplying sufficient fresh atmospheric air to the burner to maintan combustion, another fan arranged to feed the polluted air to the burner, a heat exchanger for receiving exhaust gas from the burner and wherein the exhaust gas exchanges heat with cooler air circulating in the drying chamber, means for returning the bulk of the cooled exhaust gas from the heat exchanger to the circulating fan, and an outlet for discharging to atmosphere the remainder of the cooled exhaust gas.

2. Apparatus according to claim 1, wherein the burner is a gas burner.

3. Apparatus according to claim 2, wherein the burner produces a central flame surrounded by a ring of flame.

4. Apparatus according to claim 1, which includes stenter chains for advancing the cloth through the drying chamber.

5. Apparatus according to claim 1, substantially as described herein with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. through nozzles 14 from top and bottom pressure ducts 15, 16 as most clearly shown in Figure 2. The fan 13 is driven by an electric motor 23 (Figure 2) through a belt drive 24. As best shown in Figures 3 and 5, a burner and heat exchanger system is provided at each side of each drying chamber 11. Each system includes a Thermimax burner 17, to which part of the polluted circulating through the chamber and also fresh air from an inlet 18 is fed by a centrifugal fan 19, driven by an electric motor 20 through a belt drive 21. The remainder of the circulating air returns to the circulating fan 13 through a filter. One of these filters is indicated at 22 in Figure 3, the remaining filters being omitted from the drawings for clarity. Each burner 17 receives North Sea, coal or other gas through an inlet pipe 25 and includes a hood 26 (Figure 4), which includes tubes 27 for the passage of combustion air as indicated by the arrows A and passages 28, surrounding the tubes 27, through which gas flows as indicated by the arrows B. In operation flames from the individual tubes 27 combine to form a central flame surrounded by a ring of flame produced by combustion of gas flowing through radial holes 29 in the crown. The clean exhaust gas from each burner 17 passes to a heat exchanger 30, where it gives up heat to the circulating air. The bulk of the exhaust gas is returned through exit slots 31 from the heat exchanger to the circulating fan 13 and the rest is discharged to atmosphere as a fume-free product through an outlet 32. When the stenter is being used to dry cloth and air is circulated in each drying chamber at a rate of approximately 25000 cft/min it is necessary to maintain the circulating fans 13 in operation. When, however, the stenter is used for heat setting of cloth a slower circulation of air is required, e.g. 12000 cft/min, and the fans 13 are then switched to slow speed. In the flow diagram shown in Figure 6, the portion 33 of the airflow represents polluted air which has been cooled to a temperature of, say, 1700C by contact with the cloth. The portion 34 represents clean exhaust gas from the burner 17 at a temperature of, say, 450"C. The portion 35 represents circulating air heated in the heat exchanger 30 to, say, 230"C. The portion 36 represents cooled exhaust gas returned from the heat exchanger 30 to the circulating fan 13. WHAT WE CLAIM IS:

1. A cloth drying apparatus, comprising a drying chamber, mcans for advancing cloth to be dried through the drying chamber and, within the drying chamber, a circulating fan for circulating air in the drying chamber, nozzles for discharging air circulated by the fan onto the cloth, a burner for burning polluted air which has passed through the cloth, an air inlet for supplying sufficient fresh atmospheric air to the burner to maintan combustion, another fan arranged to feed the polluted air to the burner, a heat exchanger for receiving exhaust gas from the burner and wherein the exhaust gas exchanges heat with cooler air circulating in the drying chamber, means for returning the bulk of the cooled exhaust gas from the heat exchanger to the circulating fan, and an outlet for discharging to atmosphere the remainder of the cooled exhaust gas.

2. Apparatus according to claim 1, wherein the burner is a gas burner.