Hot air circulation trolley furnace

1. This series of hot air circulation trolley type resistance furnaces is a national standard energy-saving periodic operation electric furnace. The furnace top is equipped with a hot air circulation fan, mainly used for the quenching and tempering process of high chromium steel, mold steel and other special steels. It can also be used for tempering, aging and heat treatment of high manganese steel castings, steel balls, crusher hammers, rollers, iron chromium wear-resistant materials and other mechanical parts.

2. Main Structure Introduction

This series of complete equipment consists of furnace shell (including car shell), furnace lining (including car lining and furnace bottom plate), trolley walking system, furnace door and its lifting mechanism, heating element, hot air circulation system and electric control system.

The furnace structure is an outer frame structure, and the outer shell structure is assembled and welded from steel sections (channel steel) and steel plates. This structure has the advantages of being sturdy, reliable, aesthetically pleasing, and not easily deformed during long-term high-temperature use. In order to facilitate the detection of furnace temperature uniformity, a detection hole is provided at the rear of the furnace body to facilitate the installation of thermocouples into the furnace. The hole is opened during use and closed during normal operation to prevent the temperature inside the furnace from dissipating and affecting the uniformity of the furnace temperature.

The furnace lining is made using the most advanced structure in the world - full fiber furnace lining. The side walls, top, furnace door, and rear wall of the furnace are all made of fibers. The joint between the lower part of the furnace and the trolley is constructed with heavy high alumina refractory bricks, which can effectively prevent impact. The fibers are prefabricated into modules before installation, and heat-resistant steel anchors are pre installed inside the modules. During installation, weld heat-resistant steel bolts on the furnace wall in a regular manner, and during masonry, simply tighten the prefabricated fiber modules with nuts. The compression capacity of prefabricated modules is as high as 30%, and the staggered masonry method is used during masonry. After installation, the expansion force of the modules is utilized to form a dense whole of the furnace lining, without direct gaps. The insulation performance of the furnace lining can be improved by 20%. Heating elements can be arranged around the furnace. The top masonry of the furnace is also a full fiber structure, and the fiber module masonry method is the same as the surrounding area. Due to the mechanized assembly line production of the modules, all fiber modules have the same size. After installation, they can be slightly reshaped to achieve a smooth and beautiful appearance.

Trolley: Trolley is mainly composed of trolley steel structure, trolley lining, trolley walking mechanism, etc. Trolley steel structure is a frame welded into a certain shape with steel sections and plates. There is a furnace lining constructed with ultra lightweight insulation bricks and high-strength heavy refractory bricks within the framework, and the furnace lining is covered with ZG3Cr18Mn12Si2N furnace bottom plate. The metal furnace bottom plate can isolate the impact of workpiece oxide on the electric heating element and also bear the weight of the object. The sealing between the trolley and the furnace body adopts a sealed palace structure, which has good sealing performance and does not affect the back and forth movement of the trolley, avoiding damage to the furnace body caused by friction or impact. The walking of the trolley is accomplished by the trolley's walking motor, worm reducer, sprocket, and chain driving the trolley's wheels to roll on the steel rails. The power supply for the heating elements on the trolley is provided by specialized equipment, which consists of copper trolley plugs, power supply clamping sockets, etc. The plugs and sockets are fixed by insulation boards and equipped with reliable protective covers.

Furnace door structure: The furnace door device consists of a furnace door, a furnace door lifting structure, and a furnace door clamping device. The furnace door shell is made of welded steel and sheet metal to form a sturdy frame structure, lined with refractory fiber modules. The furnace door has the advantages of good insulation performance and light weight. The lifting device of the furnace door adopts an electric device, mainly composed of guide rails, support arms, reducers, sprockets, transmission shafts, and bearing pairs. The lifting of the furnace door is driven by the forward and backward transmission of the reducer. To ensure safe operation, the furnace door lifting reducer is equipped with a braking device. After the furnace door is lowered into place, it tightly adheres to the furnace mouth under the action of the guide wheel and inclined block, preventing the overflow of heat inside the furnace, reducing the temperature gradient inside the furnace, and ensuring the uniformity of furnace temperature.

Furnace bottom plate: The trolley is equipped with a pressure resistant and high-temperature resistant cast steel furnace bottom plate. The material of the cast steel is ZG3Cr18Mn12Si2N heat-resistant steel with a thickness of δ=35mm and a commonly used temperature of ≤ 1000 ℃, ensuring that it does not deform, oxidize, or crack during use, and also preventing oxides on the workpiece from falling onto the electric heating elements inside the brick wall of the trolley. The normal service life of the furnace plate is ≥ 2 years. To ensure the normal use of the furnace bottom electric heating elements, it is necessary to frequently blow the oxide scale under the furnace bottom plate of the trolley. It is stipulated to blow once a week. During the blowing, the furnace bottom plate should be moved away, and the oxide scale in the electric heating element tank should be blown clean with compressed air. Special attention should be paid to removing conductive debris that may cause short circuits between the electric heating elements.

The heating element of the electric furnace is made of high-temperature resistant resistance alloy strip produced by Beijing Shougang, wound into a corrugated shape (resistance strip material: OCr25A15). A new special installation method is adopted to suspend on both sides of the furnace, the furnace door, the rear wall, and the trolley wire support brick, and fixed with high alumina porcelain retaining rings. The hanging structure of the resistor strip is easy to install, sturdy and reliable, with high thermal efficiency and long service life. Practice has proven that the radiation coefficient of the resistance strip is more than twice that of the resistance wire, greatly improving the thermal efficiency of the heating element.

Circulation system: In order to enhance convective heat transfer inside the furnace, eliminate heat flow blind spots at the four corners of the furnace, and achieve multi-point temperature measurement, the temperature difference inside the furnace is ≤± 5 ℃. A set of hot air circulation system is installed at the top of each of the two zones inside the furnace, and air ducts are set up in different zones. The front and rear air ducts circulate separately. The hot air inside the furnace is sucked in by a high-pressure centrifugal fan and heated along the left and right air ducts by the heating belt before flowing back to the workpiece, thus achieving the purpose of heating the workpiece. At the same time, the hot air is strongly stirred inside the furnace, uniformly filling every corner of the furnace to promote uniform temperature inside the furnace. The material of the fan blades and air ducts is 1Cr18Ni9Ti, with a thickness of ≥ 3.0mm. The material of the fan shaft of this product is 310S (which can be And it has stable high-temperature strength. Imported self-aligning bearings are selected for smooth operation, low noise, and low failure rate. The material of the fan blades is the same as that of the fan shaft.

Electrical part: It consists of two parts: a primary heating circuit and a secondary control circuit. The specific functions include: an automatic air switch, a high-power AC contactor, a fast fuse, a high-power solid-state relay and thermal protection device, a voltmeter, an ammeter, an indicator light, multiple copper core wires, and a current transformer. The automatic air switch and AC contactor are selected from famous brand products, with models YDZB1L series and CJ20 series respectively. The solid-state relay is a complete set of components from Beijing Ximandun, with model H3340ZE. The system has functions such as overcurrent, short circuit, leakage, and overheating protection. And in the case where the solid-state relay is broken down, with the help of a recorder and intermediate relay, the power supply of the heating main circuit can still be cut off to control the temperature inside the furnace. When the electric heating element of a certain phase in a certain area burns out or the fast fuse is disconnected, the corresponding ammeter can intuitively reflect it, making it easy to quickly judge and eliminate the fault; The secondary control circuit consists of digital temperature control instruments, recording instruments, intermediate relays, and thermal relays. The temperature controller adopts the Japanese Shimadzu microcomputer intelligent digital display instrument, model "SR93", which has PID parameter self-tuning function and can adjust the output power according to different heating stages. It can automatically achieve heating, insulation, power-off and other functions according to process requirements. The recorder used is the Shanghai Dahua Zhongyuan Tu temperature recorder, model "XWGJ-101", which has functions such as recording, over temperature alarm, and disconnection alarm. When overheating or disconnection occurs, the power supply to the electric furnace can be cut off through the high-power contactor of the primary circuit, ensuring the safety of the workpiece and equipment to be processed. The digital display instrument can be equipped with an RS-485 communication interface (optional), which facilitates future system upgrades and enables computer group control and distributed management.

The control cabinet shell is made using a computer programming assembly line, and the inside and outside of the cabinet shell are electrostatically sprayed with plastic, so that the control cabinet is both unified and beautiful. The size of the control cabinet is 1800 × 650 × 450mm, and the color of the control cabinet is preliminarily determined to be camel. The control cabinet can also be made according to the requirements of the demander.

Contact phone number: (0)