System and method for dynamically adjusting dryer belt speed

Abstract

A dynamically adjustable textile dryer and method of controlling a conveyor belt speed of the textile dryer is provided. The speed of the belt is utilized to more quickly adjust the temperature of the drying chamber.

Claims

1. A method for controlling a temperature of a drying chamber of a textile dryer comprising: providing a controller coupled to a first heating element for the drying chamber of the textile dryer and to an endless belt running through the drying chamber, the controller programmed to control the first heating element and the endless belt based on a sensed temperature of the drying chamber; adjusting an output of the first heating element by the controller and adjusting a speed of the belt by the controller.

2. The method of claim 1 wherein the step of adjusting an output of the heating element by the controller and adjusting a speed of the belt comprises: turning up the first heating element; and, slowing the speed of the belt.

3. The method of claim 1 wherein the step of adjusting an output of the heating element by the controller and adjusting a speed of the belt comprises: turning down the first heating element; and, increasing the speed of the belt.

4. The method of claim 1 further comprising the step of: providing a first temperature probe in the drying chamber coupled to the controller wherein the temperature probe provides a signal to the controller indicating a temperature in the drying chamber.

5. The method of claim 4 further comprising the step of: turning up the first heat element and slowing the speed of the belt by the controller when the temperature probe provides a signal to the controller that the temperature in the drying chamber is below a predetermined set point.

6. The method of claim 5 wherein the predetermined set point is 10° F. below a standard operating temperature of the drying chamber.

7. The method of claim 4 further comprising the step of: turning down the first heat element and increasing the speed of the belt by the controller when the temperature probe provides a signal to the controller that the temperature in the drying chamber is above a predetermined set point.

8. The method of claim 7 wherein the predetermined set point is 10° F. above a standard operating temperature of the drying chamber.

9. The method of claim 4 further comprising the step of: constantly monitoring the temperature in the drying chamber by the controller.

10. The method of claim 1 further comprising the step of: providing a motion sensor coupled to the controller proximate the belt.

11. The method of claim 10 further comprising the step of: monitoring a speed of the belt with the motion sensor.

12. The method of claim 1 wherein the belt extends outward from an entrance of the drying chamber of the dryer.

13. The method of claim 12 wherein the belt extends outward from an exit of the drying chamber of the dryer.

14. A method for controlling a temperature of a drying chamber of a textile dryer comprising: providing a controller coupled to a first heating element for the drying chamber of the textile dryer and to an endless belt running through the drying chamber; providing a plurality of temperature probes coupled to the controller in the drying chamber; and, adjusting an output of the first heating element by the controller and concurrently adjusting a speed of the belt by the controller to modify the temperature of the drying chamber based on a sensed temperature by the temperature probes.

15. The method of claim 14 further comprising the step of: mounting the controller to the textile dryer.

16. The method of claim 14 wherein the first heating element is a natural gas burner.

17. The method of claim 14 further comprising the step of: turning up the first heat element and slowing the speed of the belt by the controller when the temperature in the drying chamber is below a predetermined set point.

18. The method of claim 17 wherein the predetermined set point is 5° F. below a standard operating temperature of the drying chamber.

19. The method of claim 14 further comprising the step of: turning down the first heat element and increasing the speed of the belt by the controller when the temperature in the drying chamber is above a predetermined set point.

20. The method of claim 19 wherein the predetermined set point is 5° F. above a standard operating temperature of the drying chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) To understand the present invention, it will now be described by way of example, with reference to the accompanying drawings in which:

(2) FIG. 1 is a schematic view of a textile dryer in accordance with the present invention;

(3) FIG. 2 is a process flow chart for controlling aspects of the textile dryer of FIG. 1 in accordance with the present invention;

(4) FIG. 3 is a process flow chart for sensing the temperature of the drying chamber of the textile dryer of FIG. 1;

(5) FIG. 4 is a process flow chart for sensing motion of the belt of the textile dryer of FIG. 1.

DETAILED DESCRIPTION

(6) While this invention is susceptible of embodiments in many different forms, there is shown in the drawings, and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated.

(7) The present invention is directed to a textile dryer and method of operation for optimally heating and cooling a drying chamber by modifying the speed of a conveyor belt. Modification of the belt speed adjusts the amount of heat exhausted from the system.

(8) FIG. 1 shows a textile dryer 10 having a conveyor belt 12 that is used to advance textiles through a drying or heated chamber 14. The belt 12 and drying chamber 14 are supported by legs 16.

(9) The belt 12 is part of an endless loop that is moved by a belt drive 18. Textiles are placed on the belt 12 at a first end 20 and are moved through an opening 22 to the drying chamber 14 and out of an exit 24 to a second end 26. A belt motion sensor 40 is positioned proximate the first end 20 of the belt 12.

(10) The dryer 10 includes a heating element, such as propane or natural gas burner 28, and a main exhaust 30. The dryer 10 can also include an end hood 32 and an end hood exhaust 34. In addition to the main exhaust 30 and end hood exhaust 34, heat is also exhausted by the belt 12 moving through the drying chamber 14 and through the exit 24. The belt 12 also draws in cooler air through the opening 22 from outside the chamber 14.

(11) A temperature probe 36 is mounted for sensing the temperature of the drying chamber 14. More than one temperature probe—measuring different areas of the dryer 10 or chamber 14—can also be used. Additionally, other types of probes or sensors (e.g., humidity sensors) can be utilized with the dryer 10.

(12) A controller 38, such as a PLC, is mounted to the side of the dryer 10. The controller 38 is electrically coupled to the relevant components of the dryer (e.g., heating elements, belt drive, temperature probe, etc.). The controller 38 is programmed to modify the belt speed for optimal performance of the dryer 10.

(13) Specifically, in accordance with one embodiment of the invention, the controller 38 is programmed to initiate a slower than normal belt speed during start-up of the dryer 10. This is partially illustrated in FIG. 2. The slower belt speed allows the drying chamber to heat up faster than normal because heat is not being exhausted from the chamber (due to belt speed) at the same rate as the normal (i.e., higher) belt speed. Similarly, cool air is also not being drawn into the chamber at the same rate as the normal belt speed. This slower belt speed more efficiently (and therefore cost effectively) allows the dryer to warm up faster than normal. Once the drying chamber is near or at its typical drying temperature, the controller 38 increases the belt 12 to its normal or typical speed. The “normal” speed may depend on various factors, such as the type of textile being dried, type of ink used or other material(s) applied to the textile that requires drying, ambient moisture, etc.

(14) In accordance with another embodiment of the invention, the controller 38 is programmed to increase the belt speed (above its normal or typical drying speed) during shut-down of the dryer 10. Again, as partially illustrated in FIG. 2, the increased speed increases the amount of heat exhausted through the exit 24 of the drying chamber 14 by the belt 12, as well as increases the amount of cool outer air drawn through the opening 22. The chamber 14 must be cooled prior to stopping the belt 12. Otherwise, the portion of the belt 12 left in the chamber 14 could melt if it is not moving.

(15) In accordance with another embodiment of the invention, the controller is configured to increase or decrease the temperature during a drying run—by either increasing or decreasing the belt speed—depending on fluctuations of temperature in the drying chamber 14. Such fluctuations may occur, for example, by fluctuations of the heating elements, or changes in the ambient conditions, etc. The controller 38 monitors the temperature of the chamber 14 using the temperature probe 36. When the temperature moves a predetermined amount (e.g., 10° up or down), then the controller 38 signals the belt drive to increase or decrease the belt speed as appropriate. The controller 38 can concurrently adjust the heating elements in addition to adjusting the belt speed. Specifically, the controller can turn up the heating elements to increase the temperature in the chamber, or turn down the heating elements to decrease the temperature in the chamber. This control of the heating elements, combined with adjustments of the belt speed, decreases the amount of time to adjust the chamber temperature than use of either method alone.

(16) FIG. 3 illustrates an information flow for sensing temperature of the drying chamber 14 by the controller 38 from the temperature probe 36. FIG. 4 illustrates an information flow of the motion proximity sensor 40 communicating with the controller 38.

(17) Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood within the scope of the appended claims the invention may be protected otherwise than as specifically described.