The dry powder fire extinguisher is suitable for the initial fire of flammable, flammable liquids, gases and charged equipment. The ammonium phosphate dry powder fire extinguisher can be used for the initial fire of solid materials in addition to the above types of fires. But none can save metal fires.
Instructions
When the fire is extinguished, the fire extinguisher can be hand-carried or shoulder-fired and the fire extinguisher can quickly go to the fire. The fire extinguisher is put down about 5 meters from the burning place. If you are outdoors, you should choose to spray in the upwind direction. If the dry powder fire extinguisher used is of the plug-in type, the operator should tighten the spray gun with one hand, and open the lifting ring on the gas bottle. If the opening of the gas cylinder is hand-wheel type, unscrew it counterclockwise and rotate it to the highest position, then lift the fire extinguisher. When the dry powder sprayed out, quickly aim at the root of the flame. If the dry powder fire extinguisher used is a built-in gas cylinder or a pressure storage type, the operator should first unplug the safety pin on the opening handle, then live the nozzle part at the front end of the spray hose, and the other hand will open the pressure of the pressure handle. Next, turn on the fire extinguisher and extinguish it. When using a fire extinguisher or pressurized fire extinguisher with a spray hose, the pressure handle should always be pressed down by one hand and cannot be released, otherwise the injection will be interrupted.
Use caution
When using ammonium phosphate dry powder fire extinguishers to fight solid flammable materials, fire should be directed at the place where the combustion is most intense, and fire should be performed up and down and left and right. If conditions permit, the user can use the fire extinguisher to spray along the four sides of the combustion, so that the dry powder fire extinguishing agent evenly sprayed on the surface of the combustion until the flame is completely extinguished.
The use of a cart type dry powder fire extinguisher is the same as the use of a portable dry powder fire extinguisher.
"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."
Gravity Die Casting
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.
GDC is suited to medium to high volumes products and typically parts are of a heavier sections than HPDC, but thinner sections than sand casting.
There are three key stages in the process.
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The heated mould [Die or Tool] is coated with a die release agent. The release agent spray also has a secondary function in that it aids cooling of the mould face after the previous part has been removed from the die.
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Molten metal is poured into channels in the tool to allow the material to fill all the extremities of the mould cavity. The metal is either hand poured using steel ladles or dosed using mechanical methods. Typically, there is a mould [down sprue" that allows the alloy to enter the mould cavity from the lower part of the die, reducing the formation of turbulence and subsequent porosity and inclusions in the finished part.
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Once the part has cooled sufficiently, the die is opened, either manually or utilising mechanical methods.
Advantages
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Good dimensional accuracy
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Smoother cast surface finish than sand casting
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Improved mechanical properties compared to sand casting
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Thinner walls can be cast compared to sand casting
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Reverse draft internal pockets and forms can be cast in using preformed sand core inserts
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Steel pins and inserts can be cast in to the part
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Faster production times compared to other processes.
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Once the tolling is proven, the product quality is very repeatable.
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Outsourced Tooling setup costs can be lower than sand casting.
Gravity Casting Parts
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