Wood hot air drying equipment

Abstract

To provide a hot air drying device for wood, capable of heating hot air flowing through a hot air circulation path for heating board materials at a higher temperature than conventional devices or saving energy. [Solution] A hot air wood drying device 1 is equipped with a hot air circulation path P for hot air, which includes a drying area P1 that blows hot air onto the boards W to dry them, and an adjustment area P5 that collects and heats the hot air blown onto the boards W and supplies it to the drying area P1, and a temperature-raising catalyst layer 5 is disposed within the hot air circulation path P. When the temperature-raising catalyst layer 5 comes into contact with hot air that has been mixed with VOCs generated from the boards when they are dried in the drying area P1 and that has been heated to a predetermined drying temperature in the adjustment area P5, it activates the mixed VOCs and promotes an oxidation reaction, and also further heats the hot air with the reaction heat generated by the oxidation reaction.

Description

[Technical Field]

[0001] The present invention relates to a hot air wood drying device (also called a veneer dryer) used to dry board materials such as veneer sheets. [Background technology]

[0002] The hot air wood drying device has a hot air circulation path that includes a drying area where hot air is blown onto the boards to dry them, and an adjustment area where the hot air blown onto the boards is collected, heated by a heater, and supplied to the drying area. The circulating hot air dries (steam-dries) the boards (see Patent Documents 1 and 2).

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-038667 [Patent Document 2] Patent No. 7227649 Summary of the Invention [Problem to be solved by the invention]

[0004] In these hot air wood dryers, hot air heated to, for example, 180 to 200 degrees by a heater is circulated through the hot air circulation path, but if the hot air could be heated to a temperature higher than 180 to 200 degrees, the drying of boards could be made more efficient. However, the current equipment specifications and operating conditions limit the temperature to 180 to 200 degrees, and raising the temperature even higher would also create energy conservation issues.

[0005] The object of the present invention is to provide a hot air drying device for wood that can heat the hot air flowing through a hot air circulation path at a higher temperature than conventional devices or that can save energy.

[0006] In order to solve the above problems, the first aspect of the hot air drying device for wood of the present invention is as follows: A hot air drying device for wood that dries plank-shaped wood (single board, plywood, decorative board, etc.) by blowing hot air (including heated steam) onto the plank-shaped wood (single board, plywood, decorative board, etc.) while transporting the plank-shaped wood, a drying area provided for blowing hot air onto the wood transported along the transport path to dry it; A a regulation area for recovering the exhaust air from the drying area, heating it, and guiding it back to the drying area as hot air; The adjustment area includes: a blower for circulating hot air within the hot air circulation path; a heater that heats the circulating hot air to at least a predetermined drying temperature (e.g., 150°C or higher); The hot air heated by the heater to a temperature equal to or higher than the drying temperature is mixed with volatile organic compounds generated from the plate materials when the plate materials are dried in the drying area, and an oxidation catalyst layer is disposed which activates the mixed volatile organic compounds and promotes an oxidation reaction when the hot air comes into contact with the volatile organic compounds, and which heats the hot air with reaction heat (oxidation heat) generated by the oxidation reaction. 、 Furthermore, the adjustment area is provided with an outlet for connecting to an exhaust path that discharges a portion of the hot air containing the volatile organic compounds (VOCs) generated in the hot air circulation path to the outside of the hot air circulation path as exhaust air, and oxidizes and detoxifies the discharged volatile organic compounds (VOCs) (to the outside of the hot air circulation path) and then discharges them to the outside of the device, The discharge path includes: an exhaust heater that heats the exhaust air to a predetermined exhaust oxidation temperature (e.g., 300°C or higher) that is higher than the drying temperature; a purification catalyst layer that is located immediately downstream of the exhaust heater and has a function of activating the volatile organic compounds contained in the exhaust gas when the exhaust gas comes into contact with exhaust air that has been heated by the exhaust heater to a temperature equal to or higher than the exhaust oxidation temperature, thereby accelerating an oxidation reaction and rendering the exhaust air harmless; The temperature-raising catalyst layer promotes the oxidation reaction of the volatile organic compounds in a temperature range lower than the temperature at which the purification catalyst layer promotes the oxidation reaction of the volatile organic compounds.

[0007] In order to solve the above problems, the second aspect of the hot air drying device for wood of the present invention is as follows: A hot air drying device for wood that dries plank-shaped wood (single board, plywood, decorative board, etc.) by blowing hot air (including heated hot air) onto the plank-shaped wood (single board, plywood, decorative board, etc.) while transporting the plank-shaped wood, A hot air circulation path is formed inside the device, the hot air circulation path including: a drying area having a plurality of hot air passages (e.g., jet boxes, etc.) corresponding to the upper and lower conveying paths in each stage, for blowing hot air heated and adjusted to a predetermined drying temperature or higher (e.g., 150°C or higher) onto wood that is transported horizontally in parallel along conveying paths arranged in multiple stages (upper and lower stages), for drying; and an adjustment area having a single collecting adjustment path further above the hot air passage in the uppermost stage, for collecting exhaust air from each of the hot air passages, heating and adjusting it to a temperature above the drying temperature, and guiding it again as hot air to each of the hot air passages (drying areas), The collective adjustment path (adjustment area) includes: a blower for circulating hot air within the hot air circulation path; a heater that heats the circulating hot air to at least the drying temperature; The hot air heated by the heater to a temperature equal to or higher than the drying temperature is mixed with volatile organic compounds generated from the plate materials when the plate materials are dried in the drying area, and an oxidation catalyst layer is disposed which activates the mixed volatile organic compounds and promotes an oxidation reaction when the hot air comes into contact with the volatile organic compounds, and which has the function of raising the temperature of the hot air to a predetermined temperature or higher (for example, at least 20°C or higher) by reaction heat (oxidation heat) generated by the oxidation reaction. 、 Furthermore, the collecting and adjusting path is provided with an outlet for connecting to an exhaust path that discharges a portion of the hot air containing the volatile organic compounds (VOCs) generated in the hot air circulation path to the outside of the hot air circulation path as exhaust air, and oxidizes and detoxifies the discharged volatile organic compounds (VOCs) (to the outside of the hot air circulation path) and then discharges them to the outside of the device, The discharge path includes: an exhaust heater that heats the exhaust air to a predetermined exhaust oxidation temperature (e.g., 300°C or higher) that is higher than the drying temperature; a purification catalyst layer that is located immediately downstream of the exhaust heater and has a function of activating the volatile organic compounds contained in the exhaust gas when the exhaust gas comes into contact with exhaust air that has been heated by the exhaust heater to a temperature equal to or higher than the exhaust oxidation temperature, thereby accelerating an oxidation reaction and rendering the exhaust air harmless; The temperature-raising catalyst layer promotes the oxidation reaction of the volatile organic compounds in a temperature range lower than the temperature at which the purification catalyst layer promotes the oxidation reaction of the volatile organic compounds.

[0008] According to the configuration of these hot air wood dryers, volatile organic compounds (VOCs) specific to the boards are generated during drying (steam drying) of the boards. However, by providing a temperature-raising catalyst layer that promotes the oxidation reaction of these VOCs, the reaction heat (oxidation heat) generated during the oxidation reaction can be used to raise or maintain the temperature of the hot air. This allows the hot air temperature in the hot air circulation path, which was previously limited to 180 to 200 degrees, to be raised even higher (for example, to 250 degrees). At the same time, energy-saving operation of the heater can be achieved without significantly changing the hot air temperature. It is also possible to achieve both higher temperatures and energy savings. Furthermore, if the hot air wood dryer transports boards arranged in multiple rows and columns, and dries all of them in the transport path, the amount of VOCs generated will be very large, and more reaction heat (oxidation heat) will be obtained over a longer period of time, making it possible to heat the hot air efficiently. It is also expected to neutralize VOCs within the hot air circulation path.

[0009] In the adjustment area of ​​the hot air wood drying device, the temperature-raising catalyst layer is located immediately downstream of the heater, and the blower, the heater, and the temperature-raising catalyst layer are arranged in a straight line. can be configured to .

[0010] This ensures that the VOCs contained in the hot air immediately after being heated by the heater can react with the oxidation catalyst.

[0012] As a result, the temperature-raising catalyst layers (first oxidation catalyst layer, low-temperature catalyst layer, low-temperature oxidation catalyst layer) in the hot air circulation path mainly raise the temperature of the hot air through oxidation reactions at low temperatures (above a specified drying temperature) and secondarily neutralize VOCs, while the purification catalyst layers (second oxidation catalyst layer, high-temperature catalyst layer, high-temperature oxidation catalyst layer) in the exhaust path branching off from the hot air circulation path completely neutralize harmful substances including VOCs through oxidation treatment at higher temperatures (above a specified exhaust oxidation temperature).By using different catalysts in the hot air circulation path and the exhaust path, efficient hot air drying can be achieved. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a front cross-sectional view schematically showing a hot air wood drying device. [Figure 2] FIG. 10 is a perspective view schematically showing the conveyance of a plate material. [Figure 3] FIG. 2 is a side view of the hot air wood drying apparatus of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0015] As shown in Figures 1 to 3, the hot air wood drying device 1 dries board material W (board-shaped wood) by blowing hot air (including heated steam) onto it while transporting it.The device has a hot air circulation path P formed inside it, which includes a drying area P1 that is provided for blowing hot air (heated steam) onto the board material W transported along a transport path Q to dry it, and an adjustment area P5 (P2, P3, P4) that is provided for collecting exhaust air from the drying area P1, heating it, and guiding it back to the drying area P1 as hot air.

[0016] As shown in Fig. 2, each conveying path Q has a plurality of feed roll pairs 10, each consisting of a long (approximately 3 to 6.5 m long) upper roll 11 and lower roll 12, arranged at predetermined intervals, so that a plurality of rows of plate materials W are sandwiched successively between the upper and lower rolls 11, 12 of each pair and conveyed horizontally in parallel. Specifically, the upper and lower rolls 11, 12 of each pair constituting the feed roll pair 10 sandwich the plurality of rows of plate materials W from both sides in the plate thickness direction and convey them while rotating. The conveying path Q in this embodiment is provided in multiple levels (six levels in this case) on the top and bottom.

[0017] 3, the hot air wood drying apparatus 1 of this embodiment has a plurality of heating sections 2 arranged in series across the conveying paths Q. In each heating section 2, a hot air circulation path P is formed in a vertical cross section (see FIG. 1) that intersects (here, perpendicular to) the conveying direction (direction of arrow Q) of the board materials W in each stage of the conveying path Q, and hot air from the hot air circulation path P is blown onto the board materials W in each stage being conveyed along the conveying direction (direction of arrow Q) to dry them. In this way, the hot air wood drying apparatus 1 of this embodiment is a multi-stage conveying hot air drying apparatus that uses a horizontal circulation method to dry the board materials W by blowing hot air from the hot air circulation path P onto them.

[0018] The hot air circulation path P (drying area P1 and adjustment area P5 (P2, P3, P4)) will be described in detail.

[0019] The drying area P1 has a conveying path Q arranged in multiple vertical stages (multiple vertical stages) as shown in Figure 1, and has multiple hot air passages p1 corresponding to each stage of the conveying path Q to dry the plate materials W that are transported horizontally in parallel as shown in Figure 2 by blowing hot air heated to a predetermined drying temperature of 150°C or higher (here, 180°C or higher and 200°C or lower).

[0020] In this embodiment, the hot air passage p1 corresponding to the conveying path Q of each stage is formed as a jet box set 20 (ventilation duct set) provided between adjacent roll sets 10 and having approximately the same length as the upper and lower rolls 11, 12, as shown in Fig. 3. As shown in Figs. 1 and 3, the jet box set 20 includes an upper jet box 21 (upper duct) horizontally adjacent to the upper roll 11 and a lower jet box 22 (lower duct) horizontally adjacent to the lower roll 12, and these are arranged above and below each other across the corresponding conveying path Q. A plurality of nozzles are formed continuously in the longitudinal direction on the opposing surfaces of the upper and lower jet boxes 21, 22, and hot air is blown from the nozzles of the upper and lower jet boxes 21, 22 to both the front and back sides of the plate material W passing through the conveying path Q.

[0021] The adjustment area P5 has a collection area P2 (collection area) that collects (collects) the exhaust air from each hot air passage p1, a heating area P3 that heats and adjusts the exhaust air to hot air at a temperature above the drying temperature, and a supply area P4 that guides the hot air back into each hot air passage p1 (drying area P1).

[0022] The heating area P3 is a single collecting and adjusting passage located further above the topmost hot air passage p1 in order to collect the exhaust air from each hot air passage p1, heat and adjust it to a predetermined drying temperature or higher, and then guide it again as hot air to each hot air passage p1 (drying area P1).

[0023] In the heating area P3 (collective adjustment path), there are arranged a blower 4, a heater 3, and a temperature-raising catalyst layer 5. Specifically, the temperature-raising catalyst layer 5 is located immediately downstream of the heater 3, and the blower 4, the heater 3, and the temperature-raising catalyst layer 5 are arranged in this order in a straight line (lined up in the linear direction A) from the upstream side to the downstream side.

[0024] Here, blower 4 is a fan for circulating hot air within hot air circulation path P. Here, blower 4 operates within adjustment area P5 (specifically, within heating area P3) to blow hot air in linear direction A (linear air blowing direction) toward heater 3 located downstream, circulating the hot air in a fixed direction within hot air circulation path P (···→P1→P2→P3→P1→···).

[0025] The heater 3 heats the hot air circulating in the hot air circulation path P to at least a predetermined drying temperature of 150°C or higher (here, 180°C to 200°C). The heater 3 here is a heating element such as an electric heater, and is powered by a power supply. The wood hot air drying device 1 is equipped with a well-known adjustment means for controlling the heat generation level of the heater 3 based on the temperature, humidity, etc. of the hot air in the hot air circulation path P.

[0026] The temperature-raising catalyst layer 5 is an oxidation catalyst layer (first oxidation catalyst layer, low-temperature catalyst layer, low-temperature oxidation catalyst layer). The hot air heated by the heater 3 to a predetermined drying temperature of 150°C or higher is contaminated with VOCs generated from the sheet material W when the sheet material W is dried in the drying area P1. When the hot air comes into contact with the temperature-raising catalyst layer 5, the VOCs are activated, promoting an oxidation reaction. The reaction heat (oxidation heat) generated by the oxidation reaction can further increase the temperature of the hot air. The temperature-raising catalyst layer 5 in this embodiment functions to heat the hot air circulating in the hot air circulation path P to a predetermined temperature or higher (at least 20°C or higher). The hot air circulating in the hot air circulation path P is adjusted to a temperature between 180°C and 200°C by the heater 3, and then further heated to a maximum of 250°C by the temperature-raising catalyst layer 5 before being supplied to the drying area P1.

[0027] The temperature-raising catalyst layer 5 is adjusted so that its catalytic efficiency increases under temperature conditions of a predetermined drying temperature of 150°C or higher (here, 180°C or higher and 200°C or lower), and the catalytic efficiency decreases as the temperature deviates from that temperature range.

[0028] In this embodiment, the reaction heat (oxidation heat) of the oxidation reaction raises the temperature of the hot air, and the board material W is dried (steam dried) at a higher temperature than before (for example, a temperature above 200°C). However, the wood hot air drying device 1 may also be configured to perform energy-saving operation in which the heat generation level of the heater 3 is suppressed compared to before to compensate for the reaction heat (oxidation heat) of the oxidation reaction. It is also possible to achieve both energy-saving operation that suppresses heat generation and drying at a higher temperature than before.

[0029] The plate material W in this embodiment is a board material such as a veneer, plywood, decorative board, etc., and VOCs (volatile organic compounds) specific to the plate material are generated during the drying process in the drying area P1. The plate material in this embodiment is a veneer, and the VOCs generated are toluene, alpha-pinene, etc. The temperature-raised catalyst layer 5 is a low-temperature oxidation catalyst layer adjusted to undergo an oxidation reaction with the VOCs specific to the plate material to be dried at a predetermined drying temperature of 150°C or higher (here, 180°C to 200°C).

[0030] As shown in FIG. 1, the wood hot air dryer 1 is connected in the adjustment area P5 (P2, P3, P4) to an exhaust path P6 (exhaust air path) that discharges a portion of the hot air containing VOCs generated in the hot air circulation path P as exhaust air outside the hot air circulation path P. The exhaust path P6 oxidizes (high-temperature oxidizes) the discharged VOCs to render them harmless, and then discharges them to the outside of the device. An outlet 60 for connecting to the exhaust path P6 is provided in the adjustment area P5 (P2, P3, P4). In this embodiment, an outlet 60 for connecting to the exhaust path P6 is provided in the heating area P3 (collective adjustment path).

[0031] The exhaust path P6 is formed as an exhaust duct connected to the hot air circulation path P. In this embodiment, the exhaust path P6 has an outlet 60 in the heating area P3, rises upward from the outlet 60, is formed as a branch path from the hot air circulation path P, and extends to the outside (for example, outside the building in which the apparatus is housed). In this embodiment, at least in the heating area P3, adjacent heating sections 2 (see FIG. 3) communicate with each other, and the exhaust path P6 is shared by these heating sections 2.

[0032] The exhaust path P6 is provided with a well-known exhaust hot air flow rate adjusting means 61 arranged near the outlet 60 for adjusting the exhaust hot air flow rate, and a purification means 62 for neutralizing (purifying) harmful substances including VOCs generated from the sheet material W during drying before they are discharged outside the device.

[0033] The exhaust amount adjustment means 61 is provided at a predetermined position on the upstream side of the exhaust passage P6. The exhaust amount adjustment means 61 has a damper that adjusts the exhaust amount by changing the angle, a drive unit (motor) that drives the damper, and a control unit that controls the drive unit.

[0034] The purification means 62 includes an exhaust heater 63 that heats the exhaust air that has been guided through the discharge path P6 to the outside of the hot air circulation path P to a predetermined exhaust oxidation temperature of 300°C or higher (here, 400°C or higher and 600°C or lower), which is higher than the predetermined drying temperature of 150°C or higher (here, 180°C or higher and 200°C or lower), and a purification catalyst layer 65 (second oxidation catalyst layer, high-temperature catalyst layer, high-temperature oxidation catalyst layer) that is located immediately downstream of the exhaust heater 63 and has the function of activating VOCs (volatile organic compounds generated from the sheet material W when the sheet material W is dried in the drying area P1) contained in the exhaust air when it comes into contact with the exhaust air that has been heated to the predetermined exhaust oxidation temperature of 300°C or higher (here, 400°C or higher and 600°C or lower) by the exhaust heater 63, thereby promoting an oxidation reaction and neutralizing the exhaust air.

[0035] The purifying means 62 has the function of detoxifying not only the VOCs contained in the exhaust air but also other harmful substances.

[0036] Although one embodiment of the present invention has been described above, this is merely an example, and the present invention is not limited to this. Various modifications, such as additions and omissions, can be made based on the knowledge of those skilled in the art, as long as they do not deviate from the spirit of the claims.

[0037] For example, the above embodiment was a roll conveying type in which plate material (including plywood such as veneer) is sandwiched and conveyed between multiple upper and lower roll sets 10, but the present invention is not limited to this and may be of other conveying types, such as a wire mesh conveying type in which plate material is sandwiched and conveyed between a pair of upper and lower wire meshes wound in an endless band shape. [Explanation of symbols]

[0038] 1 Hot air dryer for wood 3 Heater 4. Blower 5. Temperature-raised catalyst layer 60 outlet 63 Exhaust Gas Heater 65 Purification catalyst layer W Board material (wood) Q Transport path P Hot air circulation path P1 Drying area p1 hot air passage P2 Assembly area (collection area) P3 Heating area (collective adjustment path) P4 Supply Area P5 Adjustment Area P6 Exhaust channel

Claims

1. In a hot air drying device for wood, which transports wood plates and blows hot air onto them to dry them, A hot air circulation path is formed inside the device, the hot air circulation path including a drying area provided for blowing hot air onto the wood transported along the transport path to dry it, and an adjustment area provided for collecting exhaust air from the drying area, heating it, and guiding it back to the drying area as hot air, The adjustment area includes: a blower for circulating hot air within the hot air circulation path; a heater that heats the circulating hot air to at least a predetermined drying temperature; The hot air heated by the heater to a temperature equal to or higher than the drying temperature is contaminated with volatile organic compounds generated from the plate materials when the plate materials are dried in the drying area, and an oxidation catalyst layer is provided which activates the contaminated volatile organic compounds and promotes an oxidation reaction when the hot air comes into contact with the oxidation catalyst layer, and which heats the hot air with the reaction heat generated by the oxidation reaction; Furthermore, the adjustment area is provided with an outlet for connecting to an exhaust path that discharges a portion of the hot air containing the volatile organic compounds generated in the hot air circulation path to the outside of the hot air circulation path as exhaust air, and oxidizes and detoxifies the discharged volatile organic compounds and then discharges them to the outside of the device, The discharge path includes: an exhaust heater that heats the exhaust air to a predetermined exhaust oxidation temperature that is higher than the drying temperature; a purification catalyst layer that is located immediately downstream of the exhaust heater and has a function of activating the volatile organic compounds contained in the exhaust gas when the exhaust gas comes into contact with exhaust air that has been heated by the exhaust heater to a temperature equal to or higher than the exhaust oxidation temperature, thereby accelerating an oxidation reaction and rendering the exhaust air harmless; a temperature-raising catalyst layer that promotes the oxidation reaction of the volatile organic compounds in a temperature range lower than the temperature at which the purification catalyst layer promotes the oxidation reaction of the volatile organic compounds;

2. In a hot air drying device for wood, which transports wood plates and blows hot air onto them to dry them, A hot air circulation path is formed inside the device, the hot air circulation path including: a drying area having a plurality of hot air passages corresponding to the upper and lower conveying paths in each stage, for blowing hot air heated and adjusted to a predetermined drying temperature or higher onto wood that is conveyed horizontally in parallel along conveying paths arranged in multiple stages above and below to dry the wood; and an adjustment area having a single collecting adjustment path further above the hot air passage in the uppermost stage, for collecting exhaust air from each of the hot air passages, heating and adjusting it to a temperature above the drying temperature, and guiding it again as hot air to each of the hot air passages; The collective adjustment path includes: a blower for circulating hot air within the hot air circulation path; a heater that heats the circulating hot air to at least the drying temperature; The hot air heated by the heater to a temperature equal to or higher than the drying temperature is contaminated with volatile organic compounds generated from the plate materials when the plate materials are dried in the drying area, and an oxidation catalyst layer is disposed which, when the hot air comes into contact with the oxidation catalyst layer, activates the contaminated volatile organic compounds and promotes an oxidation reaction, and which has the function of raising the temperature of the hot air to a predetermined temperature or higher by the reaction heat generated by the oxidation reaction; Furthermore, the collecting adjustment path is provided with an outlet for connecting to an exhaust path that discharges a portion of the hot air containing the volatile organic compounds generated in the hot air circulation path to the outside of the hot air circulation path as exhaust air, and oxidizes and detoxifies the discharged volatile organic compounds and then discharges them to the outside of the device, The discharge path includes: an exhaust heater that heats the exhaust air to a predetermined exhaust oxidation temperature that is higher than the drying temperature; a purification catalyst layer that is located immediately downstream of the exhaust heater and has a function of activating the volatile organic compounds contained in the exhaust gas when the exhaust gas comes into contact with exhaust air that has been heated by the exhaust heater to a temperature equal to or higher than the exhaust oxidation temperature, thereby accelerating an oxidation reaction and rendering the exhaust air harmless; a temperature-raising catalyst layer that promotes the oxidation reaction of the volatile organic compounds in a temperature range lower than the temperature at which the purification catalyst layer promotes the oxidation reaction of the volatile organic compounds;

3. The outlet connects the adjustment area between the blower and the heater to the outside of the device, and an exhaust volume adjustment means is provided near the outlet and is driven and controlled to adjust the exhaust volume; 3. The wood hot air drying device according to claim 1, wherein the exhaust passage is formed as a branch path from the hot air circulation path so that the blower, the exhaust amount adjustment means, the exhaust heater, and the purification catalyst layer are arranged in this order from upstream to downstream of the hot air circulation path, in a straight line from upstream to downstream.

4. A hot air drying device for wood as described in claim 1 or claim 2, wherein the temperature-raising catalyst layer promotes the oxidation reaction of the volatile organic compounds in a temperature range of 150°C or higher and 200°C or lower, thereby raising the temperature of the hot air to a maximum of 250°C, while the purification catalyst layer promotes the oxidation reaction of the volatile organic compounds in a temperature range of 300°C or higher and 600°C or lower.

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