(Shougang Special Steel Co., Ltd. Beijing 10 43) Small mobile air compressors have small size and light weight. Mobile is a convenient and cheap price. It is widely welcomed by all walks of life. At present, the country has one and two fires. There are sales in the hardware shop, but there are quite a few Song Li factories. Some users simply don’t know that the air compressor tanks are dangerous. It’s a one-on-one battle. The pressure vessels under safety supervision should be handled after purchase. Reporting hand, Cob one or one state / continued one body one by one small mobile air compressor storage tank belongs to a type of pressure vessel from Figure 1 mobile air compressor storage tank schematic _ in its own gas source Both are subjected to alternating load explosion wounds 1 Intake nozzle 2 Exhaust nozzle 3 Longitudinal weld 4 Ring weld is dangerous. Therefore, safety management must attach great importance to the spring safety valve on many unit tanks. Complete rust pressure 1 movement The main problem of the failure of the air compressor storage tank is that only the pressure sensing contactor pressure sensing contactor is mainly pressed by the pressure guiding tube elastic film. The tank structure and safety accessories are introduced. Spring adjusting screw The female screw moving contact static contact and the wire group of the small mobile air compressor storage tank shown in Figure 1 the tank capacity is adjusted by the adjusting nut to the spring to a certain extent, the nut is generally in the range of 0 60 20 The maximum working pressure within the tank can be locked. When the air pressure in the tank is higher than the upper limit of the spring pressing force, the 1OMP gauge material is mostly Q2 35A16M R209 and other pressure is transmitted to the spring through the film above the pipe. The safety attachment on the spring is spring safety. The pressure gauge of the valve pressure gauge is such that the movable contact and the static contact coupled with the spring are separated from the break contactor (also called pressure relay). The safety valve and the pressure sensing contact electric air compressor are stopped at a pressure lower than the spring pressing force. At the lower limit, the springs constitute a double protection extension that prevents the overpressure of the tank. The dynamic and static contacts are in contact with each other. The air compressor 12 is used. Due to the long-term operation, the components inside the contactor are prone to various types of air compressors under most use conditions. The outlet pressure is a constant-level failure such as an elastic film rupture spring. Due to the long-term pulsation-like fluctuation, the air compressor storage tank is also subjected to constant amplitude alternating load state and loses elasticity or screw skew. The more common fault is that the electric wear of the contact caused by the electrical wear of the contact in the heat-affected zone near the weld line of the storage tank under alternating load is mainly caused by the above-mentioned tendency of the intergranular fracture in the superheated coarse grain region of the contact. The liquid bridge and discharge phenomenon occurs during the breakage and closing of the longitudinal weld. The so-called hot-soil near the liquid is more likely to appear in the heat-exposed zone. The phenomenon of coarse-grained bridge in the coarse-grained zone is generally about to be separated during the contact disconnection process. The metallographic structure is basically the contact between the ferrite and the upper bainite when the contact is started. The contact contact electro-impact hardness value is nearly 2 times of the hardness value of the base material. The temperature rise causes the contact metal to be slightly melted and forms a metal with low stress concentration. The crack sensitivity is greater in the alternating tensioning bridge. Due to the action of the liquid bridge, the contact between the contacts after multiple actions is due to the material properties of the material. Uniformity, such as the presence of a group of molecules in the superimposed field, overcomes the surface tension in the directional electric field, and causes the grain boundary to slide, causing the microcracks to nucleate and splash into the positive electrode portion in the molten state to form a metal material. One step develops into a macroscopic crack such as 197 years for a unit that migrates from the cathode to the anode. This migration is called DC directed sputtering. The ZV-06/1 type air compressor tank is used for non-destructive inspection to find physical processes [' The process causes the cathode contacts to be depleted into pits, and the plurality of flat welds in the heat affected zone of the longitudinal cavity of the anode cylinder are stacked to form a convex metal migration which is an objective of the electrical contact. The deepest crack of the surface crack has reached 3 m beyond the wall thickness. The physical process increases with the increase of metal migration, resulting in a serious (4m) 07 times of the contact being deformed or even the acicular protrusion and the pit being inseparable. 3 tank safety accessories are easy to malfunction. Continuous operation of electric air compressors leads to overpressure and malignant accidents. Volume I China boiler and pressure vessel safety and safety management awareness. Due to the wide range of use of such air compressor tanks, mobility It is also very strong, coupled with the lack of safety knowledge of many purchase users, etc., requires more publicity efforts, and actively promotes the use of various units, especially township enterprises and self-employed persons, to fully realize the danger of such containers. At the same time, it is recommended that each pot inspection department investigates the situation of unlicensed use of mobile air compressor storage tanks in its area, and organizes personnel to carry out non-destructive testing and pressure test on the tank body after passing the inspection, and replenish the storage tanks with unqualified use certificates. It is strictly scrapped. Any unit or individual with a small mobile air compressor shall, according to the inspection period defined by the tank safety status level, conduct regular inspections of the tank by the local pot inspection office. And strictly implement the safety accessory verification system. In short, the safety management and use of small mobile air compressor storage tanks should be paid attention to by the competent authorities at all levels. Date one factory from a water inlet valve water tank boiler design overflow pipe rubber film device boiler water level table boiler manhole exhaust steam pipe seat boiler thermometer installation overflow pipe pass water room water pipe water tank pipe valve water tank water level table water tank people Kong Qiao. The water tank overflow port water requirement is required to block the original design of the overflow pipe of the boiler, and an overflow pipe is connected to the top of the floor-opening water tank. The water tank has a normally open manhole water level overflow pipe and a steam whistle is installed on the Wanmingbu steam pipe seat according to the user's request (the whistle has a diameter and an atmospheric gas port). With the continuous advancement of technology in Qinghai, the share of pressureless boilers in the field of domestic heating is increasing, and even large-scale central heating boilers use pressureless boilers. At the same time, accidents of pressureless boilers are also emerging. The facts give people a hint that any safety is conditional, and the safety of an absolute pressureless boiler cannot be ignored. This paper reviews the explosion facts of a normal-pressure boiler in a bank in Xining, and discusses the safe operation of the non-pressure boiler through technical analysis. A normal-pressure boiling water boiler located in the bank of a bank in Zhonghua Lane, Xining City, exploded around the afternoon of the year and the year. At that time, the furnace worker was not on the scene and injured a child. The boiler is a pressureless domestic boiler purchased from a factory in Xining in the past year. The installation of the patented product is also carried out by the factory. After the installation is completed, the plant has carried out the data technology delivery to the user, and has taken the test to burn the day. It has been running continuously and safely. Years and two months. The boiler and installation are shown in the figure for safety. The top of the boiler is provided with 40 overflow pipes. The exhaust pipe of the ventilator is not tight. The manhole of the boiler is not tight during the installation process, in order to meet the requirements of the use unit. Qualitative analysis of the installation reliability of the section. Because the upper part of the boiler is provided with an open water tank with a sleek overflow pipe, there is a whistle with a large diameter and a blistering rubber film device and a tight boiler hole. When the boiler water level is controlled at the water level gauge When the glass tube is visible, the gas and steam can be discharged into the atmosphere through the above parts. Even if the export of steam is insufficient, when the amount of steam is increased, it will first overflow a lot of steam from the above parts until the whistle sounds. All these phenomena will prompt the stover to take measures such as pressure reduction and pressure reduction, and will not take it because it is too late. A sudden explosion occurred due to measures such as pressure. The boiling water in the boiler can add water to the water tank through the pipeline valve 12. At this time, pay attention to observe the overflow condition of the water tank of the water tank, and prevent the water level of the water tank from being too high. The population of the overflow overflow pipe 10 can pass through the pipeline valve to the water room. The faucet is supplied with boiling water. This is the correct way to use the above installation design requirements. If the water inlet valve is opened to allow cold water to enter the boiler and the hot water is lifted up through the overflow pipe overflow tank, this method of use is obviously wrong for the above installation scheme. This is because the overflow pipe is used as the boiler water outlet. Over time, the accumulated scale will gradually reduce the area of ​​the overflow pipe and will eventually block the boiler, which will cause the boiler to lose its main passage through the atmosphere, which will bring unsafe factors to the boiler operation. Because of this method of adding water to the water tank, the boiler will first (3) even if the boiler and the water tank are full of water at the same time, the boiler scale is blocked (the original effective inner diameter is 50m, the effective inner diameter is only the running expansion water or the generated steam. According to the whistle mouth 8 water 10m), the use unit has always been the overflow pipe 10 when the tank overflows the mouth of the boiler manhole 7 water tank manhole 14 and so on is not the strict opening of the boiler water outlet, all the water is drained from the water tank 2 The overflowing water tank will produce a humming sound. The boiler will have a large amount of scale accumulated in the inner boiler. There are two shelves and the scale will block the pressure of the water column. As long as the boiler is on the site, the water level gauge is below and below the hood. All abnormal conditions of full water will be discovered and treated in time and will not be evenly scaled. The sm indicates that the boiler has been in full water operation and exploded. Uncleaned scale (4) The boiler will only explode when the following conditions are used. When using the unit using the wrong method in this article 2 (2), use the boiler 5 conclusion because the overflow pipe 10 is used as the boiler boiling water outlet for a long time (l Because the scale is the enemy of the safe operation of the boiler, the accumulated scale of the water is blocked or the overflow pipe 10 is basically blocked. The large amount of scale of the boiler is unavoidable. The unit is not regularly used in the boiler and the water tank are full of water. In the case where the fire is being inspected and cleaned by the scale system, the scale is blocked by the overflow pipe and the case is wang. First, the whistle will be screamed or the steam or the water level gauge cock will not periodically identify whether the boiler can continue to be safe. The swelled water will also overflow from the tightness of each hole such as the overflow hole of the tank, and the overflow pipe will be mistaken as the water supply pipe of the water tank, and if the boiler room is unmanned, it will not be processed in time. Boiler boiling water outlet during the operation of the boiler, the furnace workers will be more and more serious, and eventually the explosion will be carried out for the post. Other things are unfilled and the boiler is full of water. Therefore (5) 193 The boiler project was started on June 16, 195. The boiler explosion accident was caused by improper management and serious misconduct. The technical conditions for the use of the "normal pressure hot water boiler" (JB / T73) was implemented on July 1, 1996. A 95) Standard review is also safe (2) The occurrence of this accident makes us realize that anything is reliable because the standard 635 scrape is clear that the boiler is not an absolute non-pressure boiler not under any circumstances (including the body and the opening The connecting pipe of the water tank can be regarded as directly unsupervised with the atmosphere. Incorrect operation of the water heater. A large amount of scale has not been cleared for many years. Therefore, the installation method of the above overflow pipe cannot be considered as an abnormal condition. Of course, the size of the boiler safety equipment can not be different from the calculated value in the above standard. There is still a pressure and there is danger. It is considered that there is no pressure boiler (because the standard does not guarantee that a steel plate will burn out after the product). The point of view that will explode is really ridiculous and ignorant. Otherwise, it is not safe enough. The accident boiler can be continuously safe. It is not difficult to see that the installation method of the overflow pipe and the size of the pressureless boiler have been used for more than 5 years. If the use is improper or the management is not strict, the choice is no problem, as long as the use of 2 (4) is avoided. The safety problem of dangerous pressureless boilers cannot be ignored. The overflow pipe 10 will not be blocked by scale. The boiler will not explode. (3) Strengthen the safety education for the pressureless boiler management personnel and operators. Establish the safety operation rules and management system of the boiler room. 3 Before and after the explosion of the boiler, it is necessary to resolutely overcome the pressureless boiler. Under any circumstances, it is not according to the fact that the furnace worker said that the worm will explode through the overflow pipe at about 2 pm, and the water level of the water boiler is also added to the water tank 2 Did not reduce to normal position (received date 19-1212)...
"Gravity Die Casting. A permanent mould casting process, where the molten metal is poured from a vessle of ladle into the mould, and cavity fills with no force other than gravity, in a similar manner to the production of sand castings, although filling cn be controlled by tilting the die."
Sometimes referred to as Permanent Mould, GDC is a repeatable casting process used for non-ferrous alloy parts, typically aluminium, Zinc and Copper Base alloys.
The process differs from HPDC in that Gravity- rather than high pressure- is used to fill the mould with the liquid alloy.
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There are three key stages in the process.
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