Lost Wax Investment Castings For Impellers
There are generally two structures: one is the front half-open type, which is composed of the rear cover plate and blades. The impeller efficiency of this structure is low, and a sealing ring with an adjustable gap is required to improve the efficiency; the other is the rear half-open type. It is composed of the front cover plate and blades.
Product Introduction
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Lost Wax Investment Castings for Impellers |
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Item |
Material |
Production Process |
Sintering Temperature |
Mold |
Custom |
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Lost Wax Investment Castings for Impellers |
Customized according to customer requirements |
Investment Casting |
1680℃ |
To be customized |
Yes |
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Available Materials |
Carbon steel, alloy steel, aluminum alloy, low carbon stainless steel, titanium alloy (Ti, TC4), copper alloy, high temperature alloy (718, 713) |
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Smoothness |
Dimensional accuracy |
Product density |
Appearance treatment |
Appropriate weight |
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Roughness 1～5μm |
(±0.1%～±0.5%) |
7.8g/CM³ |
According to customer requirements |
3g～4kg) |
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Impeller Classification
Centrifugal pump impeller mainly has the following four forms (a) closed type; (b) front half open type; (c) rear half-open type; (d) open type
1—impeller; 2—rear cover; 3—hub; 4—front cover; 5—impeller sealing ring; 6—reinforcing rib
(a) Closed impeller
It consists of blades, front and rear cover plates. The closed impeller has higher efficiency and is more difficult to manufacture, and is most widely used in centrifugal pumps. It is suitable for conveying clear water, solution, and other clean liquids with low viscosity and no particles.
(b) Semi-open impeller
There are generally two structures: one is the front half-open type, which is composed of the rear cover plate and blades. The impeller efficiency of this structure is low, and a sealing ring with an adjustable gap is required to improve the efficiency; the other is the rear half-open type. It is composed of the front cover plate and blades. Since the same sealing ring as the closed impeller can be applied, the efficiency is basically the same as that of the closed impeller, and the blades also have a sealing function (back blade or auxiliary impeller) in addition to conveying liquid. The semi-open impeller is suitable for transporting liquids containing suspended solids such as solid particles and fibers. The semi-open impeller is less difficult to manufacture, lower in cost and has strong adaptability. It is gradually used in centrifugal pumps for refining and chemical industries and is used to transport clean water and liquids similar to clean water.
(d) Open impeller
There are only blades and blade ribs, and no front and rear cover impellers (the number of open impeller blades is less than 2-5 pieces). The impeller has low efficiency and is rarely used. It is mainly used to transport liquids with high viscosity and slurry liquids.
The blades of centrifugal pump impellers are generally backward curved blades. There are two types of blades: cylindrical and twisted. The use of twisted blades can reduce the load on the blades, improve the suction performance of the centrifugal pump, and improve the anti-cavitation ability, but it is difficult to manufacture and the cost is high.
Centrifugal pumps for oil refineries and the chemical industry require the impeller to be a cast or fully welded integral impeller. Welded impellers are developed and are mostly used in chemical special centrifugal pumps made of metal materials with poor casting performance (such as iron and its alloys). The geometric accuracy and surface finish of the welded impeller is better than that of Lost Wax Investment Castings for Impellers, which is beneficial to improve the efficiency of centrifugal pumps.
Shape Classification
1. Centrifugal impellers
The blade shape of a centrifugal fan impeller has several types such as single plate type, arc type and airfoil type. The airfoil blade has good aerodynamic characteristics, high efficiency, good strength, and high rigidity. The disadvantage is that the manufacturing process is complicated, and when the gas with high dust concentration is transported, the blades are easy to wear. After the blades are worn out, impurities enter the inside of the blades, which makes the impeller lose its balance and generate vibration. Flat plate straight blades are easy to manufacture, but have poor flow characteristics. Compared with airfoil blades, flat curved backward blades have lower efficiency near the highest efficiency point, but the efficiency of other operating points is quite close.
2. Forward impeller
Forward impellers generally use arc-shaped blades. Among backward impellers, large-scale fans mostly use airfoil blades. For coal-fired boiler-induced draft fans with low dust removal efficiency, arc-shaped or flat-plate blades can be used. There are many centrifugal fans with flat blades.
3. Blade shape
(a) flat blade; (b) arc narrow blade; (c) arc blade; (d) airfoil blade; (e) flat curve backward blade
Detection Systems
Copper Silica Sol Investment Casting
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