Development and use of welding equipment

In the teaching process, when welding fixed bridges, denture brackets, movable appliance accessories and medium and low-melting castings, heat sources are needed. The common heat sources for clinical use are gasoline blowpipe flame, gas blowpipe flame, high frequency induction melting alloy, carbon rod arc melting. Gold, acetylene oxygen blowing flame, tungsten electrode arc melting gold, etc., these heat sources have their own advantages and disadvantages, only suitable for clinical, not suitable for teaching. In the past, the laboratory bought an electric melting device (Hangzhou Lixue Medical Devices Co., Ltd.). Because there are fewer welding torches and more classmates, you compete for me during the experimental class, which increases the risk of experimentation and reduces the quality of teaching. This problem, all the teachers of the dental teaching and research group are based on the principle of saving money and improving the quality of teaching. After many researches and experiments, a combined melting gold welding torch has been developed, which can not only weld fixed bridges, denture brackets, active appliances. Accessories, but also can correctly melt medium and low melting alloys, and can provide services for 40 students at the same time. The production and use of the combined welding torch is now described below.

1 Materials and methods 1. 1 material diameter 10 mm copper pipe; welding torch head 40 (Zhejiang Lishui production); diameter 10 mm rubber pipe several meters; 20 L small gas tank one (Yuyao Qianjiang valve factory production, airtight experiment Pressure 2. 1 M Pa); one air compressor; one automatic pressure control combined (self-made); one set of automatic anti-gasoline return system (homemade); 20 tees.

1. 2 production method 1. 2. 1 modified liquefied gas tank for the oil storage tank in the upper part of the finished liquefied gas tank compressed gas inlet and oil hole. The copper pipe is placed from the air inlet hole. The lower end of the copper pipe is 5 cm away from the bottom of the oil storage tank. The surface of the copper pipe is drilled with dozens of small holes with a diameter of 1 mm, and three layers of medical gauze are wound to absorb the atomized gasoline. Oil device. The copper pipe is welded and sealed around the air inlet of the oil storage tank, the oiling hole is ferrule, and the bolt is sealed after refueling.

1. 2. 2 Automatic pressure induction power switch Select a suitable elastic rubber bladder, the two ends of the capsule are connected to the gas pipeline, and the upper part of the capsule is made of elastic copper platinum pressure switch. When the pressure in the oil storage tank reaches the rated working pressure (0.8 MPa), the upper part of the airbag rises and rises to lift the elastic copper and platinum, the power is cut off, the compressor stops working, and the pressure in the air tank drops to the rated working pressure (0. When the pressure drops below 5 M Pa), the copper and platinum drops, and the power is automatically turned on. The compressor starts to work, and the compressed air is sent to the gas storage tank to maintain the normal working pressure of the gas storage tank to ensure the output of the atomized gasoline.

1. 2. 3 Self-made anti-backflow valve Select a simple closed container with a diameter of 5 cm and a height of 10 cm. The upper and lower ends are respectively connected to the intake pipe and the outlet pipe. The air inlet end is provided with an elastic film valve. When the compressed air needs to be stored, When the tank is inflated, the valve is flushed by the airflow. When the compressor stops working and the airflow in the tank returns to the compressor, the valve is automatically closed by the backflow gas pressure to prevent the oil and gas in the tank from flowing back to the compressor, causing compression. The machine is damaged.

1. 2. 4 Production output working end Connect several tees to the oil mist output total rubber tube to several molten gold welding torches.

1. 2. 5 assembly of each branch connection sequence: air compressor automatic anti-backflow valve furnace pressure induction power switch storage tank output tube melting gold welding torch 1. 3 working principle compressor compressed air through anti-backflow valve, pressure induction power switch The inlet of the oil storage tank is sent to the gas tank oiling device, and the gasoline in the gas storage tank is atomized to increase the oxygen content, so that the gasoline is fully burned and the welding quality of the molten gold is improved. At the same time, the compressed air causes the sealed oil storage tank to generate a certain working pressure, and the atomized gasoline is sent to the rubber output main pipe through the output valve, and the atomized gasoline is branched to each molten gold welding torch through the three-way, when the oil storage tank is inside. When the pressure exceeds the rated working pressure, the pressure sensing switch is automatically powered off and the compressor stops working. When the pressure in the oil storage tank is less than the rated working pressure, the pressure sensing switch is automatically energized, the compressor is started, and the compressed air is input into the oil storage tank to maintain the rated working pressure. In order to prevent the compressor from stopping working, the pressure inside the tank is greater than The input pipe pressure causes oil and gas to flow back, and an automatic anti-backflow valve is connected to the input gas line to prevent the oil and gas from flowing back to damage the compressor.

1. 4 Usage Each student has a welding torch. The switch at the end of the welding gun head is opened as needed to ignite the burner. The flame is divided into four layers: the mixed flame, the combustion flame, the reducing flame and the oxidizing flame. The temperature of the oxidizing flame and the combustion flame is not high, and it is difficult to melt the metal. The reducing flame is light blue, the terminal temperature is the highest, the firepower is the strongest, and the oxygen supply is insufficient, and a small amount of carbon and hydrogen molecules are burned. The reduction helps to prevent oxidation during metal melting. The maximum temperature is up to 1 050. This type of flame is used to melt various types of medium and low melting casting alloys. The fixed bridge, denture bracket, movable appliance attachment welding, generally used in the middle of the reducing flame, pre-heating mixed flame before welding.

2 Teaching effect After more than one year of use, the welding temperature and welding quality of molten gold can fully meet the prescribed standards. The melting standard of medium and low melting casting alloy: copper alloy can be melted into a spherical shape, the surface of the film is orange-red, not too bright; gold The alloy melts into a spherical surface, pale yellow, bright as a mirror, and vibrates as the flame burns. Welding quality standard: The solder is filled with welds to firmly connect the weldments together without false welding. The flow welding phenomenon does not change the contact position of the weldment, and there is no burnt weldment and the working model alveolar ridge. The experimental project has been expanded to improve the teaching quality, teaching results of electric gold melting tools and combined melting gold welding torches.

In addition, saving money, the electric melting device can only serve one person, the cost is 880 yuan, and the combined melting gold welding torch can serve 40 people at the same time, the cost is only 320 yuan.

3 Discussing past experimental projects such as hammer-fixed bridges, denture brackets, movable appliance attachment welding, medium and low-melting castings, etc. Due to the limited number of molten gold plates, only the teachers taught the students, and now there is a combined melting gold. With the welding torch, each student can complete his or her own experimental subjects in the prescribed experimental project and experimental time.

The gas blowpipe flame is assisted by oxygen. When gas and oxygen are used to assist combustion, the oxygen switch must be slowly deflated to prevent the high temperature from being generated at a high temperature. Secondly, the gas is first ignited and finally extinguished. The operation is complicated and the danger is high. The flame of gas plus oxygen is not easy to distinguish the level, only suitable for the melting of medium and low melting alloys. The high-frequency induction melting alloy is a magnetic field generated by high-frequency alternating current, so that the heated alloy itself generates an induced current. Due to the existence of the electric resistance, electric energy can be converted into thermal energy, thereby generating high-energy heat and melting the alloy, although the operation is simple and melted. The alloy is of high quality but expensive and is only suitable for the melting of high and medium melting alloys. Carbon rod arc melting is the use of low voltage (20 36V) high current (90 100A), arc through the two-pole carbon rod, high temperature to melt the alloy, its temperature is up to about 3,000, only suitable for melting of high melting point alloy, and troublesome operation The casting quality is poor. The acetylene oxygen blows the flame, and the acetylene combustible gas is used to assist the combustion of the alloy by oxygen. The temperature can be as high as about 3,500, which is only suitable for the melting of high-melting alloys. Since acetylene is oxygenated to generate carbon dioxide during combustion, the molten alloy is also carburized, and the corrosion resistance of the alloy is lowered, and the brittleness is increased. Tungsten electrode arc melting gold: The principle is that under the oxygen protection pressure, the molten alloy is the positive electrode tungsten electrode as the negative electrode, thereby generating an electric arc to melt the alloy. Alloys that melt different melting points, but not for welding, are not suitable for teaching. Gasoline blowpipe flame principle: It is the use of the foot bellows (commonly known as the leather tiger) to compress the air into the generator, so that the gasoline is atomized and mixed with the gasoline, and is ignited through the air outlet pipe to the burner, 1 foot bellows, only Can use 1 flame tube. The combined molten gold welding torch is based on the principle of using a gasoline blowpipe flame. According to the number of flames used, the gas tank is used to store gasoline, and a certain power of the compressor is used to press the air into the oil storage tank, and then the power is automatically controlled. When the pressure is reached in the tank, the power can be automatically turned off and the compressor stops working. It is suitable for welding, and is suitable for medium and low melting casting. It is safe and reliable, easy to use and low in price.

With the combined gold welding torch, each experimental project can be carried out, and each experimental project can be shortened by 3 hours, which stabilizes the classroom order, improves the teaching quality and saves money.

Ssangyong Android Car Dvd

Car navi player for Ssangyong has accumulated sales of more than 1 million vehicles, including vans and MPV vehicles.

Car mp4 for Ssangyong of the radio sensitivity setting is high, will receive a sound, the table is not clear, but if the sensitivity is low, it can automatically filter out is not clear, if the received FM radio normal. His love of the radio, you can manually save, this function is very convenient.
Bluetooth matching can be a two-way match, the phone can be set to connect the phone to answer or car to answer, of course, Bluetooth music is less than the function, you can play the phone's music by car video for Ssangyong.

Models:car navi player(car dvd with navigation) for Ssangyong REXTON 2014,car mp4 for Ssangyong RODIUS 2014,car video for Ssangyong Actyon sports 2005-2013/Korando 2010-2013 /2014

car navi player for SsangyongSsangyong Android Car Dvd

Ssangyong Android Car Dvd,Ssangyong Android 4.4 Car Dvd,Ssangyong Android 4.1 Car Dvd,Ssangyong Android 5.1.1 Car Dvd

SHEN ZHEN KLYDE ELECTRONICS CO., LTD ,