Wood Industry One-Stop Service Solution.Offering the Widest Selection of Hydraulic Components and Solutions!
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Wood Industry One-Stop Service Solution.Offering the Widest Selection of Hydraulic Components and Solutions!
Hot press encyclopedia heating system
The heating method affects the choice of temperature, process control, and the quality of processed products when the hot press is used. The heating system of the hot press is explained in detail from the heating method, hot press plate, connection and sealing.
(1) Comparison of heating methods
The traditional heating methods are steam heating and electric heating. Steam heating is fast, but the pressure boiler needs to be configured, the pipeline pressure is high, and the steam is easy to condense into water, resulting in uneven surface temperature; Electric heating has the characteristics of fast heating, high heating temperature, easy control, etc., but it consumes a lot of power, has high operating costs, and is not easy to replace when the resistance wire fails in specific use.
The advantages of heat conduction oil heating are: high heat capacity, uniform temperature, can be heated to a very high temperature under normal pressure, small heat loss, can reduce production costs, its disadvantage is that the heating speed is slow, not easy to control the temperature. In the furniture industry, when the general hot pressing temperature requirement is not high, the hot water circulation furnace can also achieve satisfactory results, and the fixed investment and operating costs are very low.
(2) hot press plate performance
The performance of the hot press plate can be evaluated from several aspects, first of all, the use of the press plate material, then the precision of the processing, and finally the arrangement of the media holes in the hot press plate.
Hot pressing plate is generally made of whole pressed steel plate through deep hole drilling processing, mainly used for oil heating and steam heating; The other is the form of aluminum plate affixed to the surface of the welded pipeline, which is mainly used for electric heating. The use of a whole steel plate can avoid oil leakage caused by poor sealing, while the stiffness and strength are high, but the hot press plate is thicker; The latter, because it is usually in the form of thin plates, requires high processing accuracy due to the stress generated during welding and processing.
The thin hot pressing plate is easy to preheat and control the temperature, but the requirement of the workpiece is high, and the uneven thickness of the workpiece will cause the deformation of the pressing plate and affect the subsequent processing quality; The thickness of the hot press plate is conducive to increasing the heat capacity and improving the strength and stiffness, but it will increase the overall size of the press and consume more steel.
During manufacturing, the flatness and upper and lower surfaces of the hot pressing plate should be ensured to have sufficient parallelism, the flatness tolerance of the hot pressing plate should be within the range of 0.1-0.18mm, the parallelism tolerance should be within the range of 0.15-027mm, and the surface roughness of the pressing plate is 3.2μm. The temperature difference in the whole format of the hot press plate should not exceed 2-3 ° C, if the temperature difference is too large, the moisture content will be uneven, the product is easy to warp, and the strength and appearance quality of the product will be affected.
The heating channels of the hot medium flow in the hot press plate are generally not paid attention to by the furniture industry. The correct circuit design should be conducive to the flow of the hot medium, conducive to the uniform heating of the plate surface, and reduce the leakage of the hot medium as the principle. For the small press hot press plate used in the furniture industry, the single-hole double-circuit design is generally adopted, which can meet the requirements of use.
(3) Connection and sealing
It is very important to use suitable connection and sealing element for heat transfer under high temperature and high pressure.
At present, the connection pipe of the hot press plate is basically based on hose, which makes the connection very convenient, the domestic mainly based on metal hose, there are also manufacturers using imported Teflon hose, both ways can use flange connection, Teflon hose fatigue resistance is better than metal hose. Gasket materials traditionally use asbestos rubber sheet, new materials such as polytetrafluoroethylene, winding graphite, etc., its sealing effect is more ideal.
