Enterprise Name: Jiashan Wang Machinery Co., Ltd.
Contact person: Manager Zhang 15921811816
General Wang 13806713135
Address: No. 31, Lane 9, Taishan Road, Huimin Street, Jiashan County, Zhejiang Province
The following hot press manufacturers from the heating method, hot pressing plate, connection and sealing to explain the heating system of the hot press.
(1) Comparison of heating methods
The traditional heating methods are steam heating and electric heating. Steam heating has the characteristics of fast heating, high heating temperature and simple control, but it needs to be equipped with pressure boilers, high pipeline pressure and easy condensation of steam to water, which results in uneven plate surface temperature. Electric heating has the disadvantages of high power consumption, high work cost and difficult replacement of resistance wires.
The advantages of heat conducting oil heating are: high heat capacity, uniform temperature, high temperature can be heated under atmospheric pressure, low heat loss, and can reduce production costs. The disadvantage is that the heating speed is slow and temperature control is not easy. In furniture industry, when the temperature requirement of hot pressing is not high, using hot water circulating furnace can also achieve satisfactory results, and the fixed investment and work cost are very low.
(2) Function of Hot Press Plate
The function of hot-pressing plate can be commented from several aspects. First, the application of the material of hot-pressing plate, then the precision of processing, and finally the placement of medium channels in hot-pressing plate.
Hot pressing plate is generally made of whole restrained steel plate by deep hole drilling, mainly used for oil heating and steam heating; the other method is to use aluminium plate on the back surface of welded pipeline, mainly used for electric heating. The whole steel sheet can prevent oil leakage due to poor sealing. It has high stiffness and strength, but the hot-pressing plate is thicker. The latter requires high processing accuracy because of the stress in welding and processing because of the thin plate method.
Hot-pressed sheet is easy to preheat and temperature control, but the requirement for the workpiece is high. The uneven thickness of the workpiece will cause the deformation of the sheet and affect the subsequent processing quality. Thicker hot-pressed sheet is beneficial to increase the thermal capacity, forward strength and stiffness, but it will increase the exterior dimension of the press and consume more steel.
The flatness tolerance should be within 0.1-0.18 mm, the parallelism tolerance should be within 0.15-027 mm, and the surface roughness of the hot-pressed plate should be 3.2 um. Temperature difference should not exceed 2-3 C in the whole width of hot-pressing plate. 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 thermal medium activities in the hot-pressing board are generally not taken seriously by the furniture industry. Correct loop planning should be based on the principles of facilitating the activity of heat medium, uniform heating of plate surface and reducing the leakage of heat medium. As for the small press hot-pressing board used in furniture industry, the single channel and double circuit planning is generally adopted, which can satisfy the application requirements.
(3) Connection and Sealing
Choosing suitable connection method and sealing element has very important meaning for heat transfer under high temperature and high pressure.
At that time, the hot-pressing plate connection pipeline was mainly made of hoses, which made the connection very convenient. Metal hoses were the first choice in China, and imported Teflon hoses were also chosen by some manufacturers. Flange connection could be used in both ways. Teflon hoses had better anti-fatigue function than metal hoses. Asbestos rubber sheet is traditionally used as gasket material, and new materials such as PTFE and coiled graphite have more ambitious sealing effect.