US-12624895-B2 - Drying furnace with first and second hot air supply ports

US12624895B2US 12624895 B2US12624895 B2US 12624895B2US-12624895-B2

Abstract

A drying furnace comprises a plurality of drying areas that are continuously provided along a longitudinal direction of the furnace and include a first hot air supply port, a second hot air supply port, and an exhaust port. The first hot air supply port is arranged at a position below a vehicle body in the furnace shell to discharge hot air diagonally upward. The second hot air supply port is arranged at a position higher than the first hot air supply port in the furnace shell to discharge hot air diagonally downward. The exhaust port is arranged at a position lower than the first hot air supply port and the second hot air supply port in the furnace shell to discharge the hot air outside the furnace shell. The drying furnace uniformly raises the temperature of the external and internal parts of the vehicle body while shortening the furnace length.

Inventors

Satoshi Tamura
Shigeki Fujiwara

Assignees

TRINITY INDUSTRIAL CORPORATION

Dates

Publication Date: 20260512
Application Date: 20210205
Priority Date: 20200210

Claims (8)

1 . A drying furnace in which a plurality of drying areas is continuously provided along a longitudinal direction of the drying furnace, to blow hot air to a vehicle body while being conveyed in the longitudinal direction within a furnace shell, and then to dry a coating film applied to the vehicle body, characterized in that the plurality of drying areas comprises: a first hot air supply port arranged at a position below the vehicle body in the furnace shell to discharge hot air diagonally upward; a second hot air supply port arranged at a position higher than the first hot air supply port in the furnace shell to discharge hot air diagonally downward; and an exhaust port arranged at a position lower than the first hot air supply port and the second hot air supply port in the furnace shell to discharge hot air to an outside of the furnace shell characterized in that the first hot air supply port is arranged at a position of a floor-back level of the vehicle body, and the second hot air supply port is arranged at a window level position of the vehicle body.
2 . A drying furnace in which a plurality of drying areas is continuously provided along a longitudinal direction of the drying furnace, to blow hot air to a vehicle body while being conveyed in the longitudinal direction within a furnace shell, and then to dry a coating film applied to the vehicle body, characterized in that the plurality of drying areas comprises: a first hot air supply port arranged at a position below the vehicle body in the furnace shell to discharge hot air diagonally upward; a second hot air supply port arranged at a position higher than the first hot air supply port in the furnace shell to discharge hot air diagonally downward; and an exhaust port arranged at a position lower than the first hot air supply port and the second hot air supply port in the furnace shell to discharge hot air to an outside of the furnace shell characterized in that the first hot air supply port and the second hot air supply port are both configured to include a nozzle, wherein the first nozzle constituting the first hot air supply port has a suction effect that entrains surrounding air in the furnace shell.
3 . A drying furnace in which a plurality of drying areas is continuously provided along a longitudinal direction of the drying furnace, to blow hot air to a vehicle body while being conveyed in the longitudinal direction within a furnace shell, and then to dry a coating film applied to the vehicle body, characterized in that the plurality of drying areas comprises: a first hot air supply port arranged at a position below the vehicle body in the furnace shell to discharge hot air diagonally upward; a second hot air supply port arranged at a position higher than the first hot air supply port in the furnace shell to discharge hot air diagonally downward; and an exhaust port arranged at a position lower than the first hot air supply port and the second hot air supply port in the furnace shell to discharge hot air to an outside of the furnace shell characterized in that the first hot air supply port and the second hot air supply port are both configured to include a nozzle, wherein the second nozzle constituting the second hot air supply port has an effect of allowing hot air to advance straightly.
4 . The drying furnace according to claim 1 , characterized in that the first hot air supply port and the second hot air supply port are both configured to include a nozzle, wherein the first nozzle constituting the first hot air supply port has a suction effect that entrains surrounding air in the furnace shell.
5 . The drying furnace according to claim 1 , characterized in that the first hot air supply port and the second hot air supply port are both configured to include a nozzle, wherein the second nozzle constituting the second hot air supply port has an effect of allowing hot air to advance straightly.
6 . The drying furnace according to claim 2 , characterized in that the first hot air supply port and the second hot air supply port are both configured to include a nozzle, wherein the second nozzle constituting the second hot air supply port has an effect of allowing hot air to advance straightly.
7 . A drying furnace in which a plurality of drying areas is continuously provided along a longitudinal direction of the drying furnace, to blow hot air to a vehicle body while being conveyed in the longitudinal direction within a furnace shell, and then to dry a coating film applied to the vehicle body, characterized in that the plurality of drying areas comprises: a first hot air supply port arranged at a position below the vehicle body in the furnace shell to discharge hot air diagonally upward; a second hot air supply port arranged at a position higher than the first hot air supply port in the furnace shell to discharge hot air diagonally downward; and an exhaust port arranged at a position lower than the first hot air supply port and the second hot air supply port in the furnace shell to discharge hot air to an outside of the furnace shell; wherein the first hot air supply port is arranged at a position of a floor-back level of the vehicle body, and the second hot air supply port is arranged at a window level position of the vehicle body; wherein the first hot air supply port and the second hot air supply port are both configured to include a nozzle, wherein a first nozzle constituting the first hot air supply port has a suction effect that entrains surrounding air in the furnace shell and a second nozzle constituting the second hot air supply port has an effect of allowing hot air to advance straightly, wherein the first nozzle is configured so that hot air is discharged diagonally upward from the first hot air supply port so as to dry the coating film of mainly external parts including an outer floor side of the vehicle body; and wherein the second nozzle is configured so that hot air is discharged diagonally downward from the second hot air supply port, wherein hot air discharged by the second nozzle is introduced into a room through a window of the vehicle body, so as to dry the coating film of mainly internal parts including an inner floor portion of the vehicle body.
8 . The drying furnace according to claim 4 , characterized in that the first hot air supply port and the second hot air supply port are both configured to include a nozzle, wherein the second nozzle constituting the second hot air supply port has an effect of allowing hot air to advance straightly.

Description

TECHNICAL FIELD The present invention relates to a drying furnace and a coating drying method, more specifically relates to a drying furnace and a coating drying method in which plural drying areas are continuously provided along the longitudinal direction of the furnace. TECHNICAL BACKGROUND Typically, in an automobile coating line, an electrodeposition drying furnace, a sealer drying furnace, or a coating drying furnace is installed along a conveyor line that conveys an automobile body which is an object to be dried. This type of drying furnace is formed in a tunnel shape in which an entrance and an exit are provided at both ends of the furnace body for drying and curing a coating film of an automobile body while being conveyed by a conveyor in the tunnel. Generally, in the drying furnace, a plurality of drying areas is continuously provided along the longitudinal direction of the furnace. These drying areas are specifically provided with a temperature rising zone in which the wet coating film of the automobile body is quickly dried, then heated up to the preset temperature, and a temperature holding zone in which the automobile body is heated and maintained at the preset temperature. FIGS. 6 and 7 show an example of a conventional drying furnace 111. The conventional drying furnace 111 shown in FIGS. 6 and 7 has a temperature rising zone 15 that includes the first three drying areas A1, A2, and A3, and a temperature holding zone 16 that includes the last drying area A4. A hot air supply port 41 and an exhaust port 43 are both provided in each of the drying areas A1 to A4. The hot air supply port 41 is arranged at a position lower than the automobile body W1 in a furnace shell 17, and hot air is supplied from a blowout duct 23 to the hot air supply port 41. The exhaust port 43 is arranged at a position higher than the automobile body W1 in the furnace shell 17, and hot air is discharged from the exhaust port 43 to a suction duct 24. Also, the drying furnace 111 of a similar structure to this is disclosed in the following documents (see, e.g., Patent Document 1). PRIOR ARTS Patent Document Patent Document 1: Japanese Published Unexamined Patent Application No. 2005-138037 (See FIG. 1) DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention Incidentally, the time required to reach the temperature at which the coating film of the automobile body is cured is called “heating-up time”. Since the conveyance speed of the automobile body is usually constant, if the heating-up time is required to be longer, then it is necessary to make the furnace length longer. In other words, the length of the drying furnace is determined by the length of the heating-up time. In addition, the heating-up time also differs depending on the part of the automobile body. For example, comparing the external parts, which are mainly the outer plate, with the internal parts, which are primarily the inner plate, the heating-up time of the internal parts that are not easily hit by the direct hot air is inevitably more extended than that of the external parts that are easily hit by the direct hot air. Regarding the graph of FIG. 8, the horizontal axis represents time, and the vertical axis represents the body temperature. The temperature transition of the external parts is shown by a solid line, and the temperature transition of the internal parts is shown by a broken line. The drying furnace 111 is also correspondingly shown on the upper side of the graph. The graph shows that the external parts reach the preset temperature of about 160° C. relatively quickly (i.e., within 20 minutes), while the internal parts take 30 minutes or more, which means there is a difference in the heat-up time between them. For this reason, according to the conventional drying furnace, it is necessary to prioritize the heating conditions of the internal parts to secure a sufficient heating-up time. As a result, there is a drawback that the drying furnace length needs to be longer. Further, in such a case, while the furnace length is longer, the initial cost of equipment and running cost become also higher. Thus, it is required to shorten the furnace length. The present invention has been achieved in light of the above problems, and its object is to provide a drying furnace and a coating drying method that allows for raising the temperature of external parts and internal parts of a vehicle body efficiently and uniformly, thus making it possible to shorten the furnace length. Means for Solving the Above Problems To solve the above problems, the first aspect of the present invention refers to a drying furnace in which a plurality of drying areas is continuously provided along the longitudinal direction of the furnace, to blow hot air to an automobile body while being conveyed in the longitudinal direction within the furnace shell, and then to dry a coating film applied to the automobile body, characterized in that the plurality of drying areas comprises;