Technical field
The utility model belongs to a hard alloy carbonization and sintering equipment, especially a vertical type
Medium frequency carbonization furnace.
technical background
At present, the highest temperature of the vertical intermediate frequency carbonization and sintering furnace used in the production of cemented carbide
The temperature is generally below 16000 C, which is mainly used for carbonizing fine particle tungsten carbide powder and sintering process temperature
Alloys with a degree below 16000 C. The temperature measurement point of the temperature control system is selected close to the actual
The center point of the temperature. Since the core temperature is transferred from the material by heat transfer, it has
It has great thermal inertia. When the heating power is turned off, the heating power will be rushed up 100
Multiple degrees, the control system cannot find the corresponding relationship between electric power and temperature in a short time
System, not suitable for automatic temperature control; secondly, its sintering temperature does not exceed 16000 C
Sintering process that meets higher temperature requirements. At the same time, since there is no temperature measurement and control system, the protective gas
The body is inserted into the bottom of the center of the boat directly from the center of the furnace cover through a gas supply pipe, so that the gas
The hole in the hole reaches the bottom of the center of the boat, and then returns to the top of the furnace through the outside of the boat, from the side of the air inlet hole
Hole, the carbonization furnace of this inlet and exhaust method is obviously not suitable for placing the temperature probe and observation window
Above the side hole of the air intake hole, otherwise high temperature exhaust gas with dust will contaminate and burn the lens.
Technical solutions
The purpose of the utility model is to provide a higher sintering temperature and more accurate temperature measurement
It is a vertical intermediate frequency carbonization furnace suitable for automatic temperature measurement and temperature control. The technical content is as follows:
It consists of furnace shell 1, sensor 2, heating element 3, outer insulation layer 4, inner insulation layer 5
Furnace inner cover 6, material boat 7, furnace cover lifting device 8, infrared temperature measuring probe 9, filling layer
10. Furnace cover 11, exhaust pipe 12, intake pipe 13, furnace support base 14, characterized by:
The furnace shell 1 has a sandwich structure of stainless steel plates, and cooling water flows through the interlayer, and the furnace shell 1
From outside to inside are the filling layer 10, the sensor 2, the outer insulation layer 4, the inner insulation layer 5, and heat generation
Body 3, material boat 7; filling layer 10 is filled with sand;
A water seal 22 is used for sealing between the furnace cover lI and the upper flange of the furnace shell l;
The infrared temperature probe 9 is perpendicular to the furnace cover 11 and is installed at a position offset from the central axis of the furnace,
There is a temperature measurement observation window 16; the intake pipe 13 is divided into a middle hole and a side hole, the middle hole
It is perpendicular to the furnace cover 11 and is installed at the central axis of the furnace. The side hole is from the infrared temperature probe 9
Enter the installation position, the gas from the two inlet pipes enters the middle and outside of the material boat 7
Through the center bottom gas path 21 and exhaust pipe 12 to the outside of the furnace for ignition sealing; intake pipe 13
The protective gas is introduced from the middle hole and the side hole to clean the field of view and the lens;
The inner thermal insulation layer 5 uses carbon black as the internal thermal insulation material, and its thickness is 40mm-50mm
Is better; the outer insulation layer 4 is made of hollow ball alumina brick, and its thickness is 30 mm.
Between 40 mm is better; the bottom of the inner cover 6 of the furnace is graphite, and the upper layer is a stack of multiple layers of carbon felt,
The thickness is preferably 100 mm-120 mm; the heating element 3 and the material boat 7 are all graphite carbon
material;
When heating, the protective gas (generally hydrogen or nitrogen) must be passed through the furnace body to protect
The shielding gas enters and exits from the top of the furnace body.
BRIEF DESCRIPTION
Figure 1 is a schematic diagram of the utility model.
detailed description
1. Furnace shell 2, inductor 3, heating element 4, outer insulation layer 5, inner insulation layer
6. Furnace inner cover 7. Material boat 8. Furnace cover lifting device 9. Infrared temperature probe
10. Fill layer 1 1. Furnace cover 12. Exhaust pipe 13. Intake pipe 1 4. Furnace support bottom
Seat 1 5, Materials 1 6, Temperature measurement observation window 1 7, Temperature measurement point 18, Observation window 1 9, High
Temperature center observation point 20, high temperature zone 21, furnace bottom center gas path 22, water seal
As shown in Figure 1, it consists of furnace shell 1, inductor 2, heating element 3, outer insulation layer 4, inner
Insulation layer 5, furnace inner cover 6, material boat 7, furnace cover lifting device 8, infrared temperature probe
9. Filling layer 10, furnace cover l l, exhaust pipe 1 2, intake pipe 1 3, furnace support base 14,
The heating element 3 is placed in the inductor 2 and is characterized by:
The furnace shell 1 is a sandwich structure of stainless steel plates, and cooling water is passed through the interlayer,
From the outside to the inside are the filling layer 10, the outer insulation layer 4, the inner insulation layer 5, the sensor 2, and heating
Body 3, material boat 7; filling layer 10 is filled with sand;
A water seal 22 is used for sealing between the furnace cover 11 and the upper flange of the furnace shell 1;
The infrared temperature probe 9 is perpendicular to the furnace cover 11 and is installed at a position offset from the central axis of the furnace,
There is a temperature measurement observation window 16; the intake pipe 13 is divided into a middle hole and a side hole, the middle hole
It is installed perpendicular to the furnace cover 11 at the central axis of the furnace chamber, and the side hole is from the infrared temperature measuring probe 9
Enter the installation position, the gas from the two inlet pipes enters the middle and outside of the material boat 7
Through the center bottom gas path 21 and exhaust pipe 12 to the outside of the furnace for ignition sealing; intake pipe 13
The protective gas is introduced from the middle hole and the side hole to clean the field of view and the lens;
The inner thermal insulation layer 5 uses carbon black as the internal thermal insulation material, and its thickness is 40mm-50mm
Is better; the outer insulation layer 4 is made of hollow ball alumina bricks, and its thickness is 30 mm-
40 mm is better; the bottom of the inner cover 6 of the furnace is graphite-E layer is a multi-layer carbon felt stack
The thickness is preferably 100 mm-120 mm; heating element 3, boat 7 and other high temperature area components
All are graphite carbon materials;
When heating, the protective gas (generally hydrogen or nitrogen) must be passed through the furnace body to protect
The shielding gas enters and exits from the top of the furnace body.
Before heating, the material 15 of the powder or molding material to be processed is loaded into the boat 7, the boat
It is divided into upper, middle and lower sections, which can be unloaded and loaded sequentially, and the inner cover 6 and furnace are closed.
Cover 1 1. Introduce hydrogen or other protective gas (generally hydrogen) from the intake pipe 13 and open
The external water valve introduces cooling water, connects to the intermediate frequency power supply, and adds single-phase intermediate frequency power at both ends of the inductor 2,
The heating body 3 placed in the inductor 2 generates eddy current to quickly generate heat, and the furnace working temperature is fast
Rapidly and evenly increase, when the temperature reaches a certain value (7000 C-8000 C), infrared temperature probe
9 Through the temperature measurement observation window 16 to measure the temperature of the temperature measurement point 17, all subsequent temperature rises,
The heat preservation process is automatically completed by the electronic control part according to the set procedure. In order to ensure the safe operation of the system
Fully, during the heating process, the operator can adjust the center position of the high temperature area through the observation window 18 at any time.
The actual observation is carried out at the observation point 19 of the temperature center, and the shielding gas enters the intake pipe under the two observation windows
13 places are introduced into the furnace (in this way, the observation lens can be purged to ensure the lens and observation field of view
(Clear), enter the high-temperature zone 20, through the outer and center gas path of the material boat 7 from the bottom of the furnace
The heart gas path 21 is sent to the outside of the furnace through the exhaust pipe 12 for ignition, and the combustion is sealed.
The protective gas is generally reducing gas, the main function is to prevent the atmosphere from entering the furnace,
The carbon materials and materials in the oxidation furnace ensure the furnace life and product quality. The top of the furnace body is equipped with
Jack lifting device for lifting the furnace cover (1).
The upper cover of the material boat 7 under the observation window 16 deviates from the central axis of the furnace ... corresponding to a fixed distance
Set the temperature measurement point 1 7 at the position, that is, the temperature measured by the temperature measurement point 17 is the temperature of the upper surface of the material boat 7,
This position has a certain deviation from the central axis of the furnace, and its purpose is to reduce the heat of the measuring point
Inertia to meet the thermal inertia requirements of the electronic control system, making the system a closed-loop temperature
Control System.
The temperature measuring point 17 of the utility model is at the corresponding position of the upper boat cover, and the high temperature center observation point
19 is at the corresponding position of the center of the axis of the material boat; the temperature measurement point 17 measures the temperature of the upper surface of the boat,
The high-temperature center observation point 19 observes that the temperature of the center of the boat is the internal temperature of the boat. On the rise
During the temperature measurement, since the protective gas is introduced from the temperature measurement observation window 16, the temperature measurement point at a short distance
17 has a certain cooling effect and other reasons, so that the temperature measurement point 17 and the high temperature center observation point 19 are actually
The international temperature has a certain deviation. Practice has proved that the core temperature is transferred by materials through heat transfer
Passed over, it has great thermal inertia (stop the heating power and return to it when the larger work is running
, Overshooting more than one hundred degrees), the control system cannot find the match between electric power and temperature in a short time
Should be related, not suitable for automatic temperature control. The temperature measuring point 17 is different, it reflects the boat table
The surface temperature value, the thermal inertia of this temperature value is very small, which can meet the requirements of the electronic control system for thermal inertia.
By setting proper PID parameters, the value of the temperature measuring point 17 can be accurately adjusted according to the given temperature
Line heating, so that the actual material temperature changes according to the law of the given heating curve, and the temperature measurement point
The deviation between 17 and the observation point 19 of the high temperature center can be reduced by the compensation of the instrument, that is,
Said that the displayed value sent from the temperature measurement point 17 to the meter is close to the high temperature center observation point 19
Actual temperature value.
The above is summarized by performing temperature measurement on the temperature measuring point 17 with small thermal inertia, thus
Make the system a closed-loop automatic temperature measurement and temperature control system, and use the instrument compensation function to
Reduce the deviation and make the instrument display value close to the actual temperature value of the boat material.
Use the protection gas from the upper part of the furnace body into the lower part of the program
There is a big difference in structure between the body entering from the upper middle hole and the side hole out.
The vertical intermediate frequency carbonization furnace of the utility model adopts a water-cooled interlayer all-stainless steel furnace shell to protect
It proves that the furnace body has sufficient mechanical strength during high temperature operation; it has inner and outer insulation layers, the highest
The use temperature is up to 24000 C, it is an ultra-high temperature heating furnace, which can meet the coarse grain tungsten carbide
Powder (1 900 working temperature), composite tungsten carbide powder (2100 working temperature) carbon chemical
Art's requirements for ultra-high temperature.
