Resin bonded grinding wheel oxygen-free curing nitrogen tunnel kiln and control method thereof

Abstract

The application discloses a control method of a resin grinding wheel oxygen-free curing nitrogen gas tunnel kiln, 1, after a kiln car carrying resin grinding wheels to be cured enters the tunnel kiln, the feeding sealing door and the discharging sealing door are closed, the fan and the electric heating pipe in each single kiln are opened, and heating is carried out according to a set temperature rising curve; 2, the electromagnetic valves of the flue gas outlet and the air outlet are opened to exhaust, and the water vapor and impurities evaporated from the resin grinding wheels are exhausted; 3, when the temperature in the single kiln reaches 100 DEG C, the electromagnetic valve of the nitrogen gas inlet is opened to fill nitrogen gas into the single kiln, the electromagnetic valve of the flue gas outlet is closed after 80 minutes, and the electromagnetic valve of the air outlet is closed after another 80 minutes; 4, when the pressure in the single kiln reaches a set pressure, the electromagnetic valves of the flue gas outlet and the air outlet are alternately opened to exhaust; 5, when the pressure in the single kiln drops by 100 Pa, the electromagnetic valves of the flue gas outlet and the air outlet are closed; 6, steps 4-5 are repeated until the resin grinding wheels to be cured are fired.

Description

Technical Field

[0001] This invention relates to resin grinding wheel kilns, and more particularly to nitrogen tunnel kilns for oxygen-free curing of resin grinding wheels and their control methods. Background Technology

[0002] Resin grinding wheels require heating and curing after hot pressing. Currently, most equipment used for curing resin grinding wheels is electrically heated resin curing ovens (curing ovens); the hot-pressed resin grinding wheel is placed in the curing oven and heated and cured according to a set heating process (temperature rise curve).

[0003] The grinding media of resin grinding wheels mostly contain corundum, phenolic resin liquid, phenolic resin powder, cryolite powder, and colored pigments. These raw materials are easily oxidized during heating, which leads to a decrease in the sharpness and moisture resistance of the resin grinding wheel, and also causes the colored pigments in the resin grinding wheel to lose their original color. Summary of the Invention

[0004] In view of this, the present invention provides a nitrogen tunnel kiln for oxygen-free curing of resin grinding wheels and its control method, which significantly improves the hardening production efficiency of resin grinding wheels while ensuring the sharpness and deliquescence resistance of the resin grinding wheels.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The nitrogen tunnel kiln for oxygen-free curing of resin grinding wheels according to the present invention includes a tunnel kiln body equipped with a feed sealing door and a discharge sealing door. The tunnel kiln body is composed of multiple individual kilns connected in a sealed manner in sequence. Each individual kiln has the same structure, including: The first flue gas outlet, air outlet, and second flue gas outlet are sequentially and intermittently set on the top wall of the individual kiln along the center line of the tunnel kiln body. Several air inlets are provided at intervals on the lower part of the left and right side walls of the single kiln; a first nitrogen inlet is provided at the front end of the lower part of the right side wall of the single kiln, and a second nitrogen inlet is provided at the rear end of the lower part of the left side wall of the single kiln. The four corners of the upper part of the left and right side walls of the single kiln are respectively equipped with a first temperature probe, a second temperature probe, a third temperature probe, and a fourth temperature probe; a pressure probe is installed on the top wall of the single kiln. A row of electric heating tubes is installed on the left and right sides of the top wall of the single kiln, parallel to the center line of the tunnel kiln body. Each row of electric heating tubes extends downwards in a sealed and insulated manner into the inner cavity of the single kiln. Multiple fans are installed between each row of electric heating tubes and the corresponding side wall. A conveying track is installed on the bottom plate of the single kiln along the center line of the tunnel kiln body. The first flue gas outlet, the air outlet, the second flue gas outlet, and several air inlets are each equipped with a solenoid valve that is controlled to open / close by a controller; the first nitrogen inlet and the second nitrogen inlet are equipped with solenoid valves that are controlled to open / close by the controller. The detection signal output terminals of the first, second, third, and fourth temperature probes are connected to the signal input terminal of the temperature controller, and the detection signal output terminal of the pressure probe is connected to the signal input terminal of the pressure gauge; the signal output terminals of the temperature controller and the pressure gauge are respectively connected to the signal acquisition terminal of the controller.

[0006] Furthermore, the controller is a PLC programmable controller. The control output terminals Y1, Y2, Y3, Y4, Y5, and Y6 of the PLC programmable controller are respectively connected to the control input terminals of the running indicator light HHD and relays 2ZJ, 3ZJ, 4ZJ, 5ZJ, and 6ZJ. The normally open contact 2zj1 and normally closed contact 2zj2 of relay 2ZJ are respectively connected to the control terminals of the first nitrogen solenoid valve DF1 and the second nitrogen solenoid valve DF2. The normally open contact 3zj1 and normally closed contact 3zj2 of relay 3ZJ are respectively connected to the control terminals of the first air inlet solenoid valve KF1 and the second nitrogen solenoid valve DF2. The control terminals of the second air inlet solenoid valve KF2, the third air inlet solenoid valve KF3, and the fourth air inlet solenoid valve KF4 are connected; the normally open contact 4zj1 and normally closed contact 4zj2 of relay 4ZJ are connected to the control terminal of the first flue gas outlet solenoid valve PYF1; the normally open contact 5zj1 and normally closed contact 5zj2 of relay 5ZJ are connected to the control terminal of the air outlet solenoid valve PKF; the normally open contact 6zj1 and normally closed contact 6zj2 of relay 6ZJ are connected to the control terminal of the second flue gas outlet solenoid valve PYF2. The signal acquisition terminals X1 and X3 of the PLC programmable controller are connected to the signal output terminals Ws1 and Ws2 of the temperature controller, respectively, and the signal acquisition terminal X2 of the PLC programmable controller is connected to the signal output terminal Pa of the pressure gauge.

[0007] The method for controlling the nitrogen tunnel kiln for oxygen-free curing of resin grinding wheels according to the present invention includes the following steps: Step 1: After the kiln car carrying the resin grinding wheel to be cured enters the tunnel kiln, the feed sealing door and the discharge sealing door are closed, and the blower and electric heating tube in each individual kiln are turned on to heat according to the set temperature rise curve. Step 2: Open the solenoid valves of the first flue gas outlet, air outlet, and second flue gas outlet to exhaust the water vapor and impurities evaporated from the resin grinding wheel; Step 3: When the temperature inside the single kiln reaches 100-120℃, open the solenoid valves of the first nitrogen inlet and the second nitrogen inlet to fill the single kiln with nitrogen. After 80-100 minutes, close the solenoid valves of the first flue gas outlet and the second flue gas outlet. After another 80-100 minutes, close the solenoid valve of the air outlet. Step 4: When the pressure inside the single kiln reaches the set pressure of 900-1200Pa, the solenoid valves of the first flue gas outlet, air outlet, and second flue gas outlet are opened alternately in sequence to exhaust gas. Step 5: When the pressure inside the single kiln drops by 100Pa, close the solenoid valves of the first flue gas outlet, the air outlet, and the second flue gas outlet. Step 6: Repeat steps 4-5 until the resin grinding wheel to be cured is finished.

[0008] This invention continuously replenishes nitrogen into a single-unit kiln, gradually reducing the oxygen content to an oxygen-free state. Actual measurements show that the final oxygen content is only 0.04%, thus protecting the resin-cured grinding wheel from oxidation during heating. This overcomes the disadvantage of oxidation of organic pigments in resin-cured grinding wheels, increases the curing temperature, and significantly improves the sharpness, cutting endurance, and deliquescence resistance of the resin-cured grinding wheel. Furthermore, by using a nitrogen tunnel kiln to cure the resin-cured grinding wheel, the production efficiency is greatly improved compared to existing resin hardening furnaces. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of the single kiln of the present invention, which conceals the heat dissipation fan and electric heating tube.

[0010] Figure 2 This is a schematic diagram of the structure of the single kiln described in this invention, omitting the air inlet, air outlet, flue gas outlet, nitrogen inlet, temperature probe, and pressure probe.

[0011] Figure 3 This is a schematic diagram of the control circuit of the present invention.

[0012] Figure 4 This is a schematic diagram of the appearance of the nitrogen tunnel kiln for oxygen-free curing of resin grinding wheels described in this invention. Detailed Implementation

[0013] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the scope of protection of the present invention is not limited to the following embodiments.

[0014] It should be noted that in the description of this invention, relational terms such as "first" and "second", "front" and "back", "left" and "right" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0015] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0016] like Figure 1 , 2 As shown in Figure 4, the oxygen-free curing nitrogen tunnel kiln for resin grinding wheels of the present invention includes a tunnel kiln body equipped with a feed sealing door 1 and a discharge sealing door 2. The tunnel kiln body is composed of multiple individual kilns 3 connected in a sealed manner in sequence; each individual kiln 3 has the same structure, such as... Figure 1 , 2 As shown, it includes: Along the centerline 3.1 of the tunnel kiln, the first flue gas outlet 3.2, the air outlet 3.3, and the second flue gas outlet 3.4 are sequentially and intermittently set on the top wall of the individual kiln; Four air inlets 3.5, 3.6, 3.7, and 3.8 are spaced apart on the lower part of the left and right side walls of the single kiln; a first nitrogen inlet 3.9 is located at the front end of the lower part of the right side wall of the single kiln, and a second nitrogen inlet 3.10 is located at the rear end of the lower part of the left side wall of the single kiln. Temperature probes 3.11, 3.12, 3.13, and 3.14 are respectively installed at the four corners of the upper part of the left and right side walls of the single kiln. Each temperature probe is responsible for detecting the temperature of a certain area, thus turning the large space of the single kiln into a smaller space and improving the accuracy of temperature control. A pressure probe 3.15 is installed on the top wall of the single kiln, and a conveying track 3.16 is installed on the bottom plate of the single kiln along the center line 3.1 of the tunnel kiln body for the kiln car to enter and exit the tunnel kiln. On the left and right sides of the top wall of the single kiln, parallel to the center line 3.1 of the tunnel kiln body, there are rows of electric heating tubes 3.17 and 3.18 respectively. Each row of electric heating tubes extends downwards in a sealed and insulated manner into the inner cavity of the single kiln. Two fans 3.19 and 3.20 are respectively installed between each row of electric heating tubes 3.17 and 3.18 and the corresponding side wall. The two fans 3.19 on the left side wall and the two fans 3.20 on the right side wall are arranged to blow against each other. Due to the use of large fans in a counter-blowing arrangement, the wind speed and air volume are very large, which improves the heat exchange efficiency and temperature control accuracy. The first flue gas outlet 3.2, the air outlet 3.3, the second flue gas outlet 3.4, and the four air inlets 3.5, 3.6, 3.7, and 3.8 are each equipped with a solenoid valve that is controlled to open / close by a controller; the first nitrogen inlet 3.9 and the second nitrogen inlet 3.10 are each equipped with a solenoid valve that is controlled to open / close by the controller. The detection signal output terminals of the first temperature probe 3.11, the second temperature probe 3.12, the third temperature probe 3.13, and the fourth temperature probe 3.14 are connected to the signal input terminal of the temperature controller, and the detection signal output terminal of the pressure probe 3.15 is connected to the signal input terminal of the pressure gauge; the signal output terminals of the temperature controller and the pressure gauge are respectively connected to the signal acquisition terminal of the controller.

[0017] Beneficially or exemplaryly, such as Figure 3 As shown, the controller is a PLC programmable controller. The control output terminals Y1, Y2, Y3, Y4, Y5, and Y6 of the PLC are respectively connected to the control input terminals of the running indicator light HHD and relays 2ZJ, 3ZJ, 4ZJ, 5ZJ, and 6ZJ. The normally open contact 2zj1 and normally closed contact 2zj2 of relay 2ZJ are respectively connected to the control terminals of the first nitrogen solenoid valve DF1 and the second nitrogen solenoid valve DF2. The normally open contact 3zj1 and normally closed contact 3zj2 of relay 3ZJ are respectively connected to the control terminals of the first air inlet solenoid valve KF1 and the second nitrogen solenoid valve DF2. The control terminals of the second air inlet solenoid valve KF2, the third air inlet solenoid valve KF3, and the fourth air inlet solenoid valve KF4 are connected; the normally open contact 4zj1 and normally closed contact 4zj2 of relay 4ZJ are connected to the control terminal of the first flue gas outlet solenoid valve PYF1; the normally open contact 5zj1 and normally closed contact 5zj2 of relay 5ZJ are connected to the control terminal of the air outlet solenoid valve PKF; the normally open contact 6zj1 and normally closed contact 6zj2 of relay 6ZJ are connected to the control terminal of the second flue gas outlet solenoid valve PYF2. The signal acquisition terminals X1 and X3 of the PLC programmable controller are connected to the signal output terminals Ws1 and Ws2 of the temperature controller, respectively, and the signal acquisition terminal X2 of the PLC programmable controller is connected to the signal output terminal Pa of the pressure gauge.

[0018] like Figure 1 , 2 As shown in Figure 3, the control method of the nitrogen tunnel kiln for oxygen-free curing of resin grinding wheels according to the present invention includes the following steps: Step 1: After the kiln car carrying the resin grinding wheel to be cured enters the tunnel kiln, the feed sealing door 1 and the discharge sealing door 2 are closed, and the blowers 3.19 and 3.20 and the electric heating tubes 3.17 and 3.18 in each individual kiln are turned on for heating; Step 2: Open the solenoid valves PYF1, PKF, and PYF2 at the first flue gas outlet 3.2, air outlet 3.3, and second flue gas outlet 3.4 to exhaust the water vapor and impurities evaporated from the resin grinding wheel; Step 3: When the temperature inside the single kiln reaches 100-120℃, open the solenoid valves DF1 and DF2 of the first nitrogen inlet 3.9 and the second nitrogen inlet 3.10 to charge nitrogen into the single kiln. After 80-100 minutes, close the solenoid valves PYF1 and PYF2 of the first flue gas outlet 3.2 and the second flue gas outlet 3.4. After another 80-100 minutes, close the solenoid valve PKF of the air outlet 3.3. Step 4: When the pressure inside the single kiln reaches the set pressure of 900-1200Pa, the solenoid valves of the first flue gas outlet 32, air outlet 3.3, and second flue gas outlet 3.4 are opened alternately in sequence to exhaust gas. Step 5: When the pressure inside the single kiln drops by 100Pa, close the solenoid valves PYF1, PKF, and PYF2 at the first flue gas outlet, air outlet, and second flue gas outlet. Step 6: Repeat steps 4-5 until the resin grinding wheel to be cured is finished.

[0019] Finally, it should be emphasized that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A nitrogen tunnel kiln for oxygen-free curing of resin grinding wheels, characterized in that: The tunnel kiln body includes a feed sealing door and a discharge sealing door, and is composed of multiple individually sealed and connected kilns in sequence; each of the individual kilns has the same structure, including: The flue gas outlet and air outlet are arranged sequentially and at intervals on the top wall of the individual kiln along the center line of the tunnel kiln body; Several air inlets are provided at intervals on the lower part of the left and right side walls of the single kiln; a first nitrogen inlet is provided at the front end of the lower part of the right side wall of the single kiln, and a second nitrogen inlet is provided at the rear end of the lower part of the left side wall of the single kiln. The four corners of the upper part of the left and right side walls of the single kiln are respectively equipped with a first temperature probe, a second temperature probe, a third temperature probe, and a fourth temperature probe; a pressure probe is installed on the top wall of the single kiln. A row of electric heating tubes is installed on the left and right sides of the top wall of the single kiln, parallel to the center line of the tunnel kiln body. Each row of electric heating tubes extends downwards in a sealed and insulated manner into the inner cavity of the single kiln. Multiple fans are installed between each row of electric heating tubes and the corresponding side wall. A conveying track is installed on the bottom plate of the single kiln along the center line of the tunnel kiln body. The flue gas outlet, air outlet, nitrogen inlet, and several air inlets are each equipped with a solenoid valve that is controlled to open / close by a controller; The detection signal output terminals of the first, second, third, and fourth temperature probes are connected to the signal input terminal of the temperature controller, and the detection signal output terminal of the pressure probe is connected to the signal input terminal of the pressure gauge; the signal output terminals of the temperature controller and the pressure gauge are respectively connected to the signal acquisition terminal of the controller.

2. The nitrogen tunnel kiln for oxygen-free curing of resin grinding wheels according to claim 1, characterized in that: The controller is a PLC programmable controller. The control output terminals Y1, Y2, Y3, Y4, Y5, and Y6 of the PLC are respectively connected to the control input terminals of the running indicator light HHD and relays 2ZJ, 3ZJ, 4ZJ, 5ZJ, and 6ZJ. The normally open contact 2zj1 and normally closed contact 2zj2 of relay 2ZJ are respectively connected to the control terminals of the first nitrogen solenoid valve DF1 and the second nitrogen solenoid valve DF2. The normally open contact 3zj1 and normally closed contact 3zj2 of relay 3ZJ are respectively connected to the control terminals of the first air inlet solenoid valve KF1 and the second nitrogen solenoid valve DF2. The control terminals of the second air inlet solenoid valve KF2, the third air inlet solenoid valve KF3, and the fourth air inlet solenoid valve KF4 are connected; the normally open contact 4zj1 and normally closed contact 4zj2 of relay 4ZJ are connected to the control terminal of the first flue gas outlet solenoid valve PYF1; the normally open contact 5zj1 and normally closed contact 5zj2 of relay 5ZJ are connected to the control terminal of the air outlet solenoid valve PKF; the normally open contact 6zj1 and normally closed contact 6zj2 of relay 6ZJ are connected to the control terminal of the second flue gas outlet solenoid valve PYF2. The signal acquisition terminals X1 and X3 of the PLC programmable controller are connected to the signal output terminals Ws1 and Ws2 of the temperature controller, respectively, and the signal acquisition terminal X2 of the PLC programmable controller is connected to the signal output terminal Pa of the pressure gauge.

3. A method for controlling the nitrogen tunnel kiln for anaerobic curing of resin grinding wheels as described in claim 1, characterized in that: Includes the following steps: Step 1: After the kiln car carrying the resin grinding wheel to be cured enters the tunnel kiln, the feed sealing door and the discharge sealing door are closed, and the blower and electric heating tube in each individual kiln are turned on to heat according to the set temperature rise curve. Step 2: Open the solenoid valves at the flue gas outlet and air outlet to exhaust the water vapor and impurities evaporated from the resin grinding wheel; Step 3: When the temperature inside the single kiln reaches 100-120℃, open the solenoid valves of the first nitrogen inlet and the second nitrogen inlet to fill the single kiln with nitrogen. After 80-100 minutes, close the solenoid valve of the flue gas outlet. After another 80-100 minutes, close the solenoid valve of the air outlet. Step 4: When the pressure inside the single kiln reaches the set pressure of 900-1200Pa, open the solenoid valves of the flue gas outlet and air outlet alternately to exhaust the gas. Step 5: When the pressure inside the individual kiln drops by 100Pa, close the solenoid valves at the flue gas outlet and air outlet. Step 6: Repeat steps 4-5 until the resin grinding wheel to be cured is finished.

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