Pouring method of high-quality adjustable-pitch propeller

Abstract

According to the pouring method of the high-quality adjustable-pitch propeller, casting risers are arranged on the outer side of a propeller hub body of the adjustable-pitch propeller and comprise the main risers and the blind risers, and the blind risers are annularly arranged on the outer side of the waist of the propeller hub body at equal intervals; the blind riser is communicated with the outer side of the waist line of the propeller hub through a connecting channel; after pouring is completed, the blind riser continues to heat and preserve heat, a positive temperature gradient is formed at the key thick and large position of the lower end of the propeller hub, and gravity high-temperature feeding is conducted on the thick position, so that the effect of eliminating slag holes, shrinkage cavities and shrinkage porosity in the key area of the propeller hub is achieved; particularly, 100% slag inclusion shrinkage cavities are avoided below the waist line of the propeller hub, the casting quality is improved, and the operation of workers is simple; the operation is convenient.

Description

Technical Field

[0001] The present invention belongs to the technical field of adjustable pitch propellers, and in particular relates to a casting method for a high-quality adjustable pitch propeller. Background Art

[0002] The adjustable pitch propeller (CPP) is a propeller that can rotate relative to the hub. It is composed of a separate hub, blades, cylinder and other components. Compared with the fixed pitch propeller (FPP), the adjustable pitch propeller has obvious advantages:

[0003] 1. Strong adaptability to sailing conditions: When sailing conditions change, by adjusting the propeller pitch ratio H / D, the main engine can maintain its ability to generate maximum power, thereby enabling the ship to obtain greater thrust and faster speed;

[0004] 2. Good economic efficiency of the power unit: Compared with the only efficiency line of the fixed-pitch propeller, the adjustable propeller has an optimal nH / D matching curve, which can take into account the propeller efficiency and the main engine fuel consumption rate, and obtain better economy;

[0005] 3. Improved maneuverability of the ship: In addition to adjusting the ship's speed by changing the main engine speed, the pitch angle of the adjustable propeller blades can also be used to change the forward, reverse, parking and speed changes. The reversing time is short and the reverse thrust is large, which can achieve stepless speed regulation of the ship;

[0006] 4. Extended engine life: Due to the variable pitch function of the adjustable propeller, the number of times the main engine is started, shut down and the speed is changed is reduced, thereby reducing the wear of the main engine's moving parts and thermal fatigue damage to the heated parts, greatly extending the main engine's life.

[0007] The disadvantages are also obvious: difficult to manufacture, expensive to manufacture, and difficult to maintain. But overall, adjustable propellers still have greater advantages than fixed-pitch propellers. Therefore, this puts forward higher requirements for manufacturing adjustable propellers with better quality.

[0008] The hub is the most important part of the adjustable propeller. Its shape is irregular and the quality requirements are high, especially the isolated thick area below the waistline of the hub, which is prone to shrinkage, shrinkage and slag holes according to conventional manufacturing methods. Summary of the invention

[0009] In order to solve the above problems, this paper proposes a casting method for a high-quality adjustable pitch propeller. A casting riser is provided on the outside of the hub body of the adjustable pitch propeller. The casting riser includes a main riser and a blind riser. A plurality of blind risers are equidistantly arranged in an annular manner on the outside of the waist of the hub body. The blind risers are connected to the outside of the waistline of the hub through a connecting channel.

[0010] The specific casting method of the adjustable pitch propeller is as follows: when making the adjustable pitch propeller hub mold, design a suitable blind riser and connecting channel according to the heat section ratio of 2.0-3.0; set a blind riser mold at the waistline of the hub mold; embed a heat-insulating riser sleeve when shaping the hub mold; after unpacking, repair and paint can be applied to the mold for baking and casting; during the casting process, the blind riser collects slag floating on the molten metal when the hub is cast, and forms a slag pool on the top of the blind riser; after the casting is completed, the blind riser continues to generate heat and keep warm, forming a positive temperature gradient at the key thick part of the lower end of the hub, and gravity high-temperature shrinkage is performed on the thickness to achieve the effect of eliminating slag holes, shrinkage holes and shrinkage pine in the key area of ​​the hub. By setting the blind riser for the adjustable pitch propeller hub, the adjustable pitch propeller hub has good quality, especially 100% of the shrinkage holes below the waistline of the hub are free of slag inclusions, which improves the quality of the casting, is simple for workers to operate, and is convenient to operate.

[0011] The shape of the hub body is a vertical cylindrical column with a protruding arc in the middle. The center of the upper end of the hub is connected to the main riser. A hub thick layer is provided at the bottom of the hub body. A number of connecting channels are provided in a ring array on the outside of the hub body. The hub body is provided with a number of hidden risers in a ring-shaped symmetrical manner based on the transverse center line. By arranging hidden risers for the adjustable propeller hub, the adjustable propeller hub has good quality, especially below the waistline of the hub, there is 100% slag-free shrinkage cavity, which improves the quality of the casting and is simple for workers to operate and convenient to operate.

[0012] The main body of the blind riser is in the shape of a vertical strip cavity with arcs at both ends. The outer surface of the blind riser is connected to the hub through a connecting channel. A scum pool is vertically arranged at the top center of the blind riser. The bottom of the blind riser is connected to the bottom of the hub in a flush manner. The scum pool is in the shape of a vertical conduit. The bottom of the scum pool is connected to the top of the blind riser in a flush manner. The top of the scum pool is flush with the top of the main riser. The shape of the formed thermal insulation riser sleeve is a vertical elliptical sleeve. The formed thermal insulation riser sleeve is outsourced and arranged on the outside of the blind riser. The blind riser continues to generate heat and keep warm, forming a positive temperature gradient at the key thick part of the lower end of the hub, and performing gravity high-temperature shrinkage compensation on the thickness to achieve the effect of eliminating slag holes, shrinkage holes and shrinkage in the key area of ​​the hub. The formed thermal insulation riser is used to gradually guide the temperature, and is connected to the blind riser body in a flush manner up and down, thereby ensuring the overall consistency. The scum pool is used to filter out the molten metal, ensuring that more scum can be stored in the blind riser.

[0013] The main riser is in the shape of a cup-shaped conductive body, the bottom end of the main riser is in communication with the top surface of the hub body, a plurality of overflow pipes are arranged in a ring-shaped manner in the middle of the outer side of the main riser, the outer side of the main riser is in communication with the auxiliary riser through the overflow pipe, the auxiliary riser is in the shape of a cup-shaped cylinder, the bottom of the auxiliary riser is connected to the top surface of the hub body, the main riser is arranged in the middle of the outer side of the auxiliary riser in a plug-in communication manner, a filter screen is arranged on the inner surface of the connection between the auxiliary riser and the overflow pipe, the filter screen is fitted with the end face of the overflow pipe, and the casting efficiency and casting quality of the hub are improved through the cooperation of the main riser and the auxiliary riser.

[0014] The connecting channel is a circular conductive flow channel, and a plurality of connecting channels are adjacently arranged in an annular shape at equal intervals on the outer side of the hub.

[0015] Beneficial effects:

[0016] By setting a blind riser on the adjustable propeller hub, the adjustable propeller hub has good quality, especially 100% slag inclusion shrinkage cavity below the hub waistline, which improves the casting quality and is simple and convenient for workers to operate.

[0017] By continuing to generate heat and keep warm through the blind riser, a positive temperature gradient is formed at the key thick area at the lower end of the hub, and gravity high-temperature shrinkage is performed on the thickness to achieve the effect of eliminating slag holes, shrinkage holes and shrinkage in the key areas of the hub.

[0018] The temperature is gradually guided by forming the heat-insulating riser, and it is connected flush with the main body of the concealed riser up and down, thus ensuring the overall consistency.

[0019] The scum pool is used to filter out the molten metal, ensuring that more scum can be stored in the blind riser. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic cross-sectional view of a blind riser of a casting method for a high-quality adjustable pitch propeller;

[0021] In the figure; 1. hub body, 2. hub thick layer, 3. connecting channel, 4. formed insulation riser sleeve, 5. main riser, 6. slag pool, 7. blind riser. DETAILED DESCRIPTION

[0022] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to embodiments and drawings. The embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0023] Hub body 1, hub thick layer 2, connecting channel 3, formed heat-insulating riser sleeve 4, main riser 5, slag pool 6, blind riser 7.

[0024] like Figure 1 As shown;

[0025] The hub body 1 is in the shape of a vertical cylindrical column with a protruding arc in the middle. The upper center of the hub is connected to the main riser 5. A hub thick layer 2 is provided at the bottom of the hub body 1. A plurality of connecting channels 3 are provided in an annular array on the outside of the hub body 1. The hub body 1 is provided with a plurality of hidden risers 7 in an annular symmetrical manner based on the transverse midline. The main shape of the hidden riser 7 is a vertical strip cavity with arcs at both ends. The outer surface of the hidden riser 7 is connected to the hub through the connecting channel 3. A scum pool 6 is vertically provided at the top center of the hidden riser 7. The bottom of the hidden riser 7 is connected to the bottom end of the hub in a flush manner. The scum pool 6 is in the shape of a vertical conduit. The bottom end of the scum pool 6 is connected to the top of the hidden riser 7 in a flush manner. The top of the scum pool 6 is flush with the top of the main riser 5. The molded thermal insulation riser sleeve 4 is in the shape of a vertical elliptical sleeve, and the molded thermal insulation riser sleeve 4 is outsourced and arranged on the outside of the blind riser 7. The main riser 5 is in the shape of a cup-shaped conductive body. The bottom end of the main riser 5 is connected to the top surface of the hub body 1, and a plurality of overflow pipes are arranged in the middle ring form on the outer side of the main riser 5. The outer side of the main riser 5 is connected to the auxiliary riser through the overflow pipe. The auxiliary riser is in the shape of a cup-shaped cylinder, and the bottom of the auxiliary riser is connected to the top surface of the hub body 1. The main riser 5 is arranged in the middle of the outer side of the auxiliary riser in a plug-in conductive manner. A filter screen is provided on the inner surface of the connection between the auxiliary riser and the overflow pipe, and the filter screen is fitted with the end face of the overflow pipe. The connecting channel 3 is a circular conductive flow channel, and a plurality of connecting channels 3 are adjacently and equidistantly arranged in annular shapes on the outside of the hub.

[0026] Implementation examples;

[0027] a. When making the adjustable propeller hub mold, design appropriate blind risers 7 and connecting channels according to the heat section ratio of 2.0-3.0;

[0028] b. Set a hidden riser 7 mold at the waistline of the hub mold;

[0029] c. Pre-embed the heat-insulating riser sleeve when shaping the hub mold;

[0030] d. After unpacking, you can fix the shape and apply paint before baking and pouring;

[0031] e. During the pouring process, the blind riser 7 collects the slag floating on the molten metal when the hub is poured, forming a slag pool on the top of the blind riser 7;

[0032] f. After pouring, the blind riser 7 continues to generate heat and keep warm, forming a positive temperature gradient at the key thick part of the lower end of the hub, and performing gravity high-temperature shrinkage compensation at the thickness to achieve the effect of eliminating slag holes, shrinkage holes and shrinkage in the key area of ​​the hub.

[0033] According to the physical properties of copper alloy, parting is performed at the waistline of the adjustable propeller hub, and suitable forming heat-insulating heating dark risers 7 are placed above and below the parting surface. The dark risers 7 can collect the slag floating on the molten metal during the hub pouring, forming a slag pool at the top of the dark risers 7; and after the pouring is completed, the dark risers 7 continue to heat and insulate, forming a positive temperature gradient at the key thick part of the lower end of the hub, and gravity high-temperature shrinkage compensation is performed at the thickness, so as to achieve the effect of eliminating slag holes, shrinkage holes, and shrinkage pores in the key areas of the hub.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A casting method for a high-quality adjustable pitch propeller, wherein a casting riser is provided on the outer side of a hub body of the adjustable pitch propeller, and the casting riser includes a main riser and a blind riser, and is characterized in that: A plurality of hidden risers are provided in an annular manner at equal intervals on the outside of the waist of the hub body, and the hidden risers are connected to the outside of the waistline of the hub through a connecting channel. The specific casting method of the adjustable pitch propeller is as follows; a. When making the hub mold of the adjustable propeller, design appropriate blind risers and connecting channels according to the heat section ratio of 2.0-3.0; b. Set a blind riser mold at the waistline of the hub mold; c. Pre-embed the heat-insulating riser sleeve when shaping the hub mold; d. After unpacking, you can fix the shape and apply paint before baking and pouring; e. During the pouring process, the blind riser collects the slag floating on the molten metal when the hub is poured, forming a slag pool on the top of the blind riser; f. After pouring, the blind riser continues to generate heat and keep warm, forming a positive temperature gradient at the key thick area at the lower end of the hub, and gravity high-temperature shrinkage compensation is performed on the thickness to achieve the effect of eliminating slag holes, shrinkage holes and shrinkage in the key area of ​​the hub.

2. A casting method for a high-quality adjustable pitch propeller according to claim 1, characterized in that: The shape of the hub body is a vertical cylindrical column with a protruding arc in the middle. The center of the upper end of the hub is connected to the main riser. A hub thick layer is provided at the bottom of the hub body. A plurality of connecting channels are provided in a circular array on the outside of the hub body. The hub body is provided with a plurality of hidden risers in a circular symmetrical manner based on the transverse center line.

3. A casting method for a high-quality adjustable pitch propeller according to claim 1, characterized in that: The main body of the blind riser is a vertical strip cavity with arcs at both ends. The outer surface of the blind riser is connected to the hub through a connecting channel. A scum pool is vertically arranged at the top center of the blind riser, and the bottom of the blind riser is flush with the bottom end of the hub.

4. The blind riser of the adjustable pitch propeller according to claim 3, characterized in that: The scum pool is in the shape of a vertical guide tube, the bottom end of the scum pool is connected to the top end of the blind riser, and the top end of the scum pool is flush with the top end of the main riser.

5. A casting method for a high-quality adjustable pitch propeller according to claim 3, characterized in that: The shape of the molded heat-insulating riser sleeve is a vertical elliptical sleeve, and the molded heat-insulating riser sleeve is arranged on the outside of the blind riser in an outsourcing manner.

6. The blind riser of an adjustable pitch propeller according to claim 2, characterized in that: The main riser is in the shape of a cup-shaped conductor, the bottom end of the main riser is in communication with the top surface of the hub body, a plurality of overflow pipes are provided in the form of a ring in the middle of the outer side of the main riser, and the outer side of the main riser is in communication with the auxiliary riser through the overflow pipes.

7. The blind riser of the adjustable pitch propeller according to claim 6, characterized in that: The auxiliary riser is in the shape of a cup-shaped cylinder, the bottom of the auxiliary riser is connected to the top surface of the hub body, the main riser is provided in the middle of the outer side of the auxiliary riser in a plug-in conduction manner, and a filter screen is provided on the inner surface of the connection between the auxiliary riser and the overflow pipe, and the filter screen is in contact with the end surface of the overflow pipe.

8. The blind riser of the adjustable pitch propeller according to claim 3, characterized in that: The connecting channel is a circular conductive flow channel, and a plurality of connecting channels are adjacently arranged in an annular shape at equal distances on the outer side of the hub.

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