Fine temperature control electric heating furnace and control method

Abstract

The invention relates to a fine temperature control electric heating furnace and a control method, the electric heating furnace is provided with a plurality of out-of-furnace cold air inlet channels and in-furnace gas exhaust channels, in the heating or heat preservation process, a fan sends in-furnace high-temperature gas to a set position, so that the temperature in the furnace and the temperature of a workpiece are uniform; in the process that the workpiece is cooled along with the furnace, the switching valve on the cold air channel outside the furnace adjusts the air inflow, the switching valve on the exhaust pipeline inside the furnace adjusts the air displacement, and cooling of the electric heating furnace is conducted according to the workpiece requirement and the set cooling speed. The device has the advantages of fine temperature control, uniform workpiece heating, good product quality and the like.

Description

Technical Field

[0001] The present invention relates to an electric heating furnace, and in particular to an electric heating furnace and a control method thereof, which utilizes a ventilation fan to promote the flow of high-temperature airflow in the furnace according to a set program and finely control temperature changes, and belongs to the field of mechanical design and heat exchange technology. Background Art

[0002] Electric heating furnaces are commonly used equipment in industrial production, and there are many types of them. Electric heating furnaces convert electrical energy into thermal energy to heat the workpiece, so that the temperature of the workpiece is increased or kept warm, thereby meeting the requirements of the thermal processing process. Existing electric heating furnaces have the advantages of high thermal efficiency, easy operation, low pollution, good safety and a high degree of automation. However, because the workpiece is placed at the bottom of the furnace, the temperature in different areas of the furnace is different, which makes the workpiece heated unevenly, affecting the quality of the workpiece. Some methods must be taken to solve this problem. For example: installing a fan on the upper part of the furnace cavity to stir the gas in the furnace or using an air duct to transport the hot air to the lower part of the furnace cavity for circulation. These measures cannot completely solve the problem. If a workpiece with a complex shape is encountered, the above solution will be even worse. In the heat treatment process, the workpiece needs to be cooled with the furnace after the heating is stopped, and the cooling rate also needs to be strictly controlled. However, most existing electric heating furnaces do not have a device to control the rate at which the furnace temperature is reduced.

[0003] In summary, people urgently need to design an electric heating furnace with high versatility, good reliability and full functions. Summary of the Invention

[0004] The present invention provides an electric heating furnace with fine temperature control and a control method. A fan with ventilation function is used to transport the gas in the upper part of the furnace cavity to the two sides of the furnace inner wall for relative ejection. The ventilation volume is controlled to adjust the furnace cooling rate, thereby achieving fine control of the temperature in the furnace.

[0005] In order to achieve the above-mentioned object, the present invention provides an electric heating furnace with fine temperature control, comprising: an electric heating furnace and a fan, wherein the electric heating furnace comprises a furnace body and a furnace cavity, an electric heating device is provided on the inner wall of the furnace body, the fan is mounted on the top of the furnace body, and its wind wheel is mounted on the top of the furnace, an upper air inlet is above the wind wheel, and a lower air inlet is below the wind wheel, and the characteristics are:

[0006] The electric heating furnace is provided with a plurality of air inlet channels and air outlet channels;

[0007] The air inlet passage includes an air passage outside the furnace and a gas passage inside the furnace;

[0008] The air passage outside the furnace is connected to the upper air inlet, and a switch valve is provided at the inlet thereof;

[0009] The gas channel in the furnace is connected to both the upper air inlet and the lower air inlet;

[0010] The air outlet channel is connected to the exhaust pipe and the inlet of the gas pipeline;

[0011] The outlet of the exhaust pipe is connected to the outside of the furnace, and a switch valve is provided at the outlet;

[0012] The gas transmission pipeline is arranged on the furnace walls on both sides, and an air jet hole is provided at the outlet thereof, and a control device is arranged on the air jet hole.

[0013] Furthermore, the control device provided on the air jet hole is a gate.

[0014] Preferably, the switch valve is an electromagnetic switch regulating valve.

[0015] Control method of the above electric heating furnace:

[0016] When the electric heating furnace is heating up or keeping warm: the on-off valves on the air passage outside the furnace and the exhaust pipe are closed, and the fan delivers the high-temperature gas above the furnace cavity to the set position in the furnace through the gas pipeline and the air jet holes, so that the high-temperature gas in the furnace circulates. The control device controls the opening of some or all of the air jet holes according to the working conditions, and adjusts the air jet volume of the air jet holes to adjust the temperature of various parts of the workpiece to achieve uniform temperature in the furnace and on the workpiece;

[0017] When the workpiece is cooled with the furnace: the switch valves on the air channel outside the furnace and the exhaust pipe are opened, and the fan draws air from outside the furnace into the furnace for ventilation and cooling. The switch valve on the air channel outside the furnace adjusts the air intake volume, and the switch valve on the exhaust pipe adjusts the exhaust volume, so that the furnace operates at the set cooling rate.

[0018] Preferably, the switch valves provided on the air passage outside the furnace and the exhaust pipe are opened or closed at the same time.

[0019] The present invention provides an external cold air intake channel and an internal gas exhaust channel in the electric heating furnace. During the heating or holding process, a fan delivers the hot air inside the furnace to a set position, equalizing the temperature inside the furnace and the workpiece. As the workpiece cools with the furnace, an on-off valve in the external cold air channel adjusts the air intake, while an on-off valve in the internal exhaust duct adjusts the exhaust volume, ensuring that the electric heating furnace cools at the desired workpiece and the set cooling rate.

[0020] The invention has the advantages of fine temperature control, uniform heating of workpieces, and good product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Attachment Figure 1 This is a schematic diagram of the main cross-sectional structure of the present invention.

[0022] Attachment Figure 2 For attachment Figure 1 AA cross-sectional structural diagram,

[0023] Attachment Figure 3 For attachment Figure 1 Schematic diagram of the BB cross-section structure,

[0024] Attachment Figure 4 For attachment Figure 1 Schematic diagram of the C-direction structure.

[0025] In the accompanying drawings, 1 is the furnace chamber, 2 is the furnace top, 3 is the fan base, 4 is the wind wheel, 5 and 5' are the air channels outside the furnace, 501 is the switch valve, 6 and 6' are the gas pipelines, 601 is the air injection hole, 602 is the gate, 7 and 7' are the exhaust pipes, 701 is the switch valve, 8 is the workpiece, and 9 and 9' are the furnace side walls. DETAILED DESCRIPTION

[0026] Attachment Figure 1 、 2 , 3, and 4 show embodiments of five centrifugal fans for temperature control of an electric heating furnace.

[0027] As attached Figure 1 and 4 As shown, the fan bases 3 of five fans are simultaneously placed on the roof 2 of the electric heating furnace. The impeller 4 of each fan is installed in a fan housing and placed together with the fan housing at the top of the furnace cavity. The external air ducts 5 and 5' are respectively connected to the upper air inlet of the upper end of the impeller 4. Air enters the fan housing from the external air ducts 5 and 5', respectively. On-off valves 501 control the opening and closing of the external air ducts 5 and 5' and the amount of air entering. An outlet channel is provided on each side of the fan. One outlet channel is connected to the gas supply pipe 6 and the exhaust pipe 7, respectively, and the other outlet channel is connected to the gas supply pipe 6' and the exhaust pipe 7', respectively. The gas supply pipes 6 and 6' deliver the gas exhausted by the fans to the air injection hole 601, from which it is discharged into the furnace cavity. The exhaust pipes 7 and 7' deliver the gas exhausted by the fans to the outside of the furnace. The on-off valve 701 controls the opening and closing of the exhaust pipes 7 and 7' and the amount of gas exhausted.

[0028] As attached Figure 1 、 2 In the embodiment shown in FIG. 3 , the gas pipelines 6 and 6 ′ are respectively arranged on the side walls 9 and 9 ′ of the furnace, and the gas pipelines 6 and 6 ′ are provided with injection holes 601 toward the furnace, and control gates 602 are provided on the injection holes 601. The control gates 602 on the injection holes 601 horizontally opposite to the workpiece 8 are opened or partially opened, and the other control gates 602 are closed.

[0029] When the electric heating furnace is heating up or keeping warm: the switch valves 701 and 501 are closed, and the fan sends the high-temperature gas above the furnace cavity to the set position in the furnace through the air injection holes 601 on the gas pipelines 6 and 6'. The control gate 602 on the air injection hole 601 horizontally opposite to the workpiece 8 is partially or fully opened to adjust the temperature of various parts of the workpiece 8, so that the high-temperature gas in the furnace circulates and achieves uniform temperature in the furnace and the workpiece 8.

[0030] When the workpiece is cooled with the furnace: the switch valves 701 and 501 are opened, the fan draws air outside the furnace into the furnace for ventilation and cooling, the switch valve 501 adjusts the air intake volume, and the switch valve 701 adjusts the exhaust volume, so that the furnace runs at the set cooling rate.

Claims

1. A fine temperature controlled electric heating furnace, comprising: An electric heating furnace and a fan, the electric heating furnace comprises a furnace body and a furnace cavity, an electric heating device is provided on the inner wall of the furnace body, the fan is installed on the top of the furnace body, and its wind wheel is installed on the top of the furnace, the upper air inlet is above the wind wheel and the lower air inlet is below the wind wheel, characterized in that: The electric heating furnace is provided with a plurality of air inlet channels and air outlet channels; The air inlet passage includes an air passage outside the furnace and a gas passage inside the furnace; The air passage outside the furnace is connected to the upper air inlet, and a switch valve is provided at the inlet thereof; The gas channel in the furnace is connected to both the upper air inlet and the lower air inlet; The air outlet channel is connected to the exhaust pipe and the inlet of the gas pipeline; The outlet of the exhaust pipe is connected to the outside of the furnace, and a switch valve is provided at the outlet; The gas transmission pipeline is arranged on the furnace walls on both sides, and an air jet hole is provided at the outlet thereof, and a control device is arranged on the air jet hole.

2. The electric heating furnace with fine temperature control according to claim 1, characterized in that: The control device provided on the air jet hole is a gate.

3. The electric heating furnace with fine temperature control according to claim 1, characterized in that: The switch valve is an electromagnetic switch regulating valve.

4. The method for using the electric heating furnace according to claim 1, wherein: When the electric heating furnace is heating up or keeping warm: the on-off valves on the air passage outside the furnace and the exhaust pipe are closed, and the fan delivers the high-temperature gas above the furnace cavity to the set position in the furnace through the gas pipeline and the air jet holes, so that the high-temperature gas in the furnace circulates. The control device controls the opening of some or all of the air jet holes according to the working conditions, and adjusts the air jet volume of the air jet holes to adjust the temperature of various parts of the workpiece to achieve uniform temperature in the furnace and on the workpiece; When the workpiece is cooled with the furnace: the switch valves on the air channel outside the furnace and the exhaust pipe are opened, and the fan draws air from outside the furnace into the furnace for ventilation and cooling. The switch valve on the air channel outside the furnace adjusts the air intake volume, and the switch valve on the exhaust pipe adjusts the exhaust volume, so that the furnace operates at the set cooling rate.

5. The method for using the electric heating furnace according to claim 4, characterized in that: The switch valves arranged on the air passage outside the furnace and the exhaust pipe are opened or closed at the same time.

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