The furnace is used with PID intelligent temperature program control system, which can automatically indicate, control and record the working state of the furnace temperature of 2. 1. The equipment consists of two fixed furnaces, a furnace body with one end fixed at 14m and a movable heating cover structure. The fixed furnace is equipped with a vacuum muffle tank, and the workpiece is heated in the vacuum muffle tank, so that the furnace temperature uniformity is high (≤ 10℃).
2.2. All-fiber energy-saving furnace lining is more than 30% energy-saving than composite brick-concrete furnace lining. 2.3. The movable furnace cover is equipped with a fixed furnace door with one end sealed with the vacuum muffle tank, and at the same time, two furnace covers are equipped with movable furnace doors. The fixed furnace body is equipped with an open furnace door, one end of which is sealed with the vacuum muffle tank, and the other end is equipped with a sealing device, so that it can be tightly sealed with the furnace mouth when assembled with the movable furnace cover.
2.4. A soft seal with a side knife is adopted between the furnace and the furnace cover. When the furnace cover enters the furnace, the side knife of the furnace is inserted into the fiber of the furnace cover, so that the furnace is sealed and insulated, and the seal is simple and reliable.
2.5. The bearing seat of the muffle groove is provided with a roller groove, and the bearing roller is placed in the groove, so that the muffle groove can advance and retreat freely when it expands with heat and contracts with cold.
2.6. Strong cooling fans and pipes are arranged at the end of the furnace, which can speed up the cooling speed after the heating process of the muffle tank is completed according to the needs and improve the utilization rate of the furnace.
2.7. High-precision intelligent temperature program control system adopts Fuji high-precision PID intelligent program controller in Japan. The heating and heat preservation programs can be set by themselves, and the furnace temperature in each area can be automatically programmed and controlled. Medium-long drawing paper recorder is used for temperature recording, which can record the temperature in all areas of the furnace synchronously. This type is intuitive, convenient and advanced.
2.8. The furnace bottom and the furnace top are equipped with corresponding temperature measurement and control points to control the temperature balance of the furnace within the allowable range, reduce the deformation of the muffle tank during heating and cooling, prolong the service life of the muffle tank and facilitate operation.
2.9. The equipment has high degree of automation, safe and reliable operation, long service life and convenient operation and maintenance; 4. 1 and JB225 1 Basic Technical Conditions of Resistance Furnace
4.2.GB 1006 Basic technical conditions of thermoelectric equipment
Code for Design and Safety of Refractory Fiber Lining in 4.3.JB/T7629-94
4.4.GB9452-2003 Measurement Method of Effective Heating Zone of Heat Treatment Furnace
4.5.SJ3 1426- 1994 Integrity Requirements and Inspection and Evaluation Methods of Trolley Heat Treatment Furnace. The furnace is mainly composed of furnace cover, furnace cover driving mechanism, energy-saving all-fiber refractory lining, high-temperature and high-radiation electric heating elements, soft seal locking mechanism, furnace platform, furnace platform conductive electrode box and intelligent PID temperature program control system.
5. 1. Furnace cover shell:
It is mainly welded by high-quality national standard steel skeleton and steel plate, which ensures the sealing performance and sufficient rigidity of the furnace. All welds are even and smooth, and there are no defects such as pores, inclusions and incomplete fusion. The furnace shell has a straight and beautiful appearance. The extraction rods of the electric heating elements outside the furnace shell are distributed centrally, and a protective cover is arranged outside.
5.2. Furnace cover drive mechanism:
The furnace cover is driven by a self-propelled motor reducer (8m/min);
***5 rows of wheels, 3 rows of driving wheels, 2 rows of driven wheels, wheel material ZG55, axle material 45# forging and tempering;
The assembly bearing adopts heavy-load double-roller bearing and steel bearing seat;
5.3. Energy-saving all-fiber refractory lining:
The side walls of the furnace lining are anchored by high-quality aluminum silicate needle-punched refractory fiber folding modules (the fire resistance limit is greater than 1050℃). The lining with this structure is one of the most widely used lining in large and medium-sized energy-saving furnaces at present. It folds high-temperature ceramic refractory fiber into an organ shape, embeds a metal anchor at the same time, and gives a certain amount of compression to make a fiber module. After installation and molding, the modules are mutually extruded to form a seamless integral thermal insulation lining.
This type of furnace lining is made of all-fiber materials with excellent thermal insulation performance, so it has excellent power saving performance, good structural thermal shock stability and rapid cooling and heat resistance.
The lining of this structure has the advantages of low density (240Kg/m3) and small heat capacity, which is more than 75% lighter than that of light-weight heat-insulating firebrick lining, and the heat capacity is only 1/9 of that of light-weight heat-insulating firebrick lining, which greatly reduces the heat storage of the lining, which means that the lining absorbs less heat, and the furnace with the same power heats up quickly, saving energy significantly, and the external temperature rise of the furnace body is ≤40℃. The thermal conductivity of the lining of this structure is low, and at 600℃, the thermal conductivity is less than or equal to 0.25 W/m.k, which is only 1/8 of that of the light-weight heat-insulating firebrick lining.
The whole furnace is built in strict accordance with the national furnace building standards, which is superior to the national standards.
5.4. High temperature and high radiation electric heating elements;
5.4. 1. adopts high temperature and high radiation electrothermal alloy flat strip (material: 0Cr25Al5), with low surface load (≤ 1.6w/cm2) and long service life.
5.4.2. The resistance belt is wound back and hung on the inner surface of the furnace with a special high-temperature white corundum porcelain screw anchor, which is reasonably arranged around the furnace and at the bottom of the furnace.
5.4.3, the distribution of electric heating elements, according to the furnace before, during and after * * * points six temperature control zone distribution in the furnace, and local concentrated lead out, the periphery has a protective cover.
5.4.4 Electric heating elements have good oxidation resistance, high temperature resistance and high surface load, and are designed with reasonable structural parameters. The electric heating element is firmly installed, durable and reliable, and easy to maintain. When the electric heating element is maintained, it can be directly reshaped, welded and replaced in the visible and tangible position.
5.5. Furnace door:
The oven door is mainly welded by high-quality steel plates, and a high-temperature aluminum silicate needle-punched fiber folding module is installed in the oven door. The furnace door is well sealed, which ensures that the furnace is always in a closed state during the production process, eliminates the escape of high-temperature furnace gas, ensures the uniformity of the furnace temperature and enhances the energy-saving effect.
5.6. Two high-intensity furnaces:
5.6. 1. The cross beam and longitudinal beam of the furnace frame are welded by combination of high-quality section steel and thick steel plate side guards. The expansion joint of the car body is designed reasonably, which minimizes the thermal deformation of the car body in use and can better meet the heat treatment and heating of long workpieces.
5.6.2. The surface of the furnace is built with high-quality high-temperature heavy refractory bricks, which has high high-temperature strength and large bearing capacity. The bottom of the car is built with high-strength lightweight insulation bricks to ensure that the temperature outside the bottom of the car does not exceed 50℃.
5.6.3. Both the furnace and the movable furnace are equipped with double safety limiting mechanisms and interlocking mechanisms with the furnace door to ensure safe operation. The movable furnace body has flexible access, accurate positioning and convenient inspection and maintenance.
5.6.4. The bearing base of muffle furnace tank is installed on the hearth, and there is a roller groove on the base, and the bearing roller is placed in the groove, so that the muffle furnace tank can advance and retreat freely when it expands with heat and contracts with cold.
5.6.5. Strong cooling fans and pipes are arranged at the end of the furnace, which can accelerate the cooling speed after the heating process of muffle tank is completed according to the needs and improve the utilization rate of the furnace.
5.7. Furnace conductive electrode box:
The heating power of the heating element on the hearth is provided by the electrode box at the door, which consists of a fixed knife insert and a movable knife insert. Both the insert knife and the plug are made of copper, and the plug mounting plate is made of poly (diphenyl ether) laminated glass cloth, so the installation and connection are simple and reliable. The accuracy and reliability of the contact of the furnace cover power supply mode are ensured.
5.8. Soft seal of furnace side knife:
Heat-resistant steel side knives are used for soft sealing between the furnace and the furnace body. When the furnace cover enters the furnace, the side knives are inserted into the fibers of the furnace body, so that the furnace is sealed and isolated from the outside. This kind of sealing is simple and reliable, and the sealing effect is good.
5.9.PID intelligent temperature program control system;
5.9. 1. The control system is designed for the heating furnace. The control cabinet is integrated, and the front and rear doors are open. The front wiring has a dust-proof ventilation window at the lower part and a dust-proof exhaust device at the top.
5.9.2. Main functions:
The main loop and control loop of the control part are separated, and both of them are equipped with air switches and circuit breakers as operating units, which is not only beneficial to debugging and maintenance, but also can reliably protect the system from short circuit and overload. The whole control system has the functions of temperature setting, locking, fault alarm and temperature recording.
The temperature control is controlled and adjusted by the imported intelligent expert PID self-tuning program, which can control the continuous output of the solid-state controllable integrated power regulating module and control the furnace temperature in an ideal state, with high control accuracy (65438 0℃) and good furnace temperature uniformity. At the same time, the power can be set manually in a certain range, the power ratio of each section can be coordinated, the use function of the furnace can be expanded, and the thermal inertia can be reduced. Multi-stage furnace can realize almost synchronous heating, heat preservation and cooling of each stage through this function adjustment, so as to meet the temperature balance in the heat treatment process of products in the furnace to the greatest extent and reduce uneven thermal deformation.
The control system has the functions of temperature display and temperature curve recording during heat treatment. The six-point temperature recorder can record the working state of the furnace temperature synchronously. The furnace is divided into six temperature control zones according to the front of the furnace and the back of the furnace, and the position of temperature measurement points is set reasonably, which can avoid the large deformation of the vacuum tank due to uneven heating. Each area of the control system has safety and automatic protection functions, such as audible and visual alarm for over-temperature disconnection, automatic cut-off of heating power supply, etc.
Each control cabinet is equipped with a voltage indicator and a three-phase current indicator.
5.9.3. Main configuration of the system:
Combination cabinets (2 sets) (customized)
PID intelligent temperature program controllers (6)
Power intelligent controllers (6)
Thyristor power regulating module (400A):(6 sets)
High temperature thermocouples (K-split cores) (6 pieces)
Six-point temperature recorder (1 set)
Other instruments and circuits: (famous in China)
Safety guarantee system:
In order to ensure the safe use of the equipment, the control system has various interlocking protection functions and acousto-optic alarm devices.
Alarm function: when the furnace temperature deviation exceeds the set value, alarm and stop heating at the same time to prevent overheating from damaging the furnace body and heating elements. The SCR power regulating module is equipped with a temperature monitoring point, which has the functions of over-temperature, over-current protection, fault alarm and so on. Ensure the personal safety of equipment and operators. 1, PLC system
1. 1. The system uses Siemens programmable controller (PLC for short) to control vacuum pumps, valves, etc. The important operation steps of PLC control are not only internal software interlocking, but also external hardware interlocking of PLC output.
1.2. Schematic diagram of control system composition
Hardware design and implementation of the system.
Siemens S7-200 series (CPU224CN type) PLC is selected as the control center. This series of PLC has digital input and output functions, rich functional instructions, 14 24VDC inputs, 10 relay output terminals EM223 module: extended digital module, 8 24VDC input terminals, 8 output terminals, a total of ***22 input terminals, 18 output terminals, which can meet the control requirements of the whole system.
Siemens S7-200 series PLC is programmed with STEP7 4.0 programming language on PC, and finally downloaded and solidified into CPU. It ensures the operability and reliability of the program.
The flow chart is as follows:
Third, the vacuum system:
The furnace is equipped with two vacuum systems, each of which consists of an H 150 slide valve pump, a ZJB 1200 Roots pump, a KT800 diffusion pump, a 2X-70 rotary vane pump, a cooling pump and a pneumatic high vacuum flapper valve, as shown in the following figure.