A screw pump for LNG ships

Abstract

The present invention discloses an LNG marine screw pump, comprising a pump body, a motor and a muffler mounted on the pump body, the pump body comprising a rotor assembly, a shell sleeved outside the rotor assembly, a front cover assembly located at one end of the rotor assembly and mounted on the shell, a side cover assembly located at the other end of the rotor assembly and mounted on the shell, a rear cover mounted on the side cover assembly, and a bearing gland mounted on the front cover assembly, wherein the rotor assembly is sealed in the pump body by a lip seal in conjunction with a special mechanical seal to achieve gas-liquid sealing; the rotor assembly comprises an active threaded rod and a driven threaded rod, the active threaded rod and the driven threaded rod are connected and transmitted by gears, and the active threaded rod and the driven threaded rod are meshed with each other, and the motor is mounted on the active threaded rod. The rotor assembly in the device is sealed in the pump body by a lip seal in conjunction with a special mechanical seal to achieve gas-liquid sealing, and the sealing effect is better.

Description

Technical Field

[0001] The invention belongs to the technical field of screw pumps, and in particular relates to a screw pump for LNG ships. Background Art

[0002] During use, the screw pump can fill gas or liquid into the interior of the pump body through the inlet of the screw pump. The gas or liquid follows the operation of the pump body itself to achieve circulation operation, and then the liquid or gas follows the rotation of the pump body to be discharged through the outlet set on the pump body.

[0003] Patent application number CN202122951404.7 is a long-life screw pump. In order to solve the problem in the prior art that the pump body is prone to generate excessively high temperatures during operation, thereby reducing the service life of the pump body, the following technical solution is provided, including a motor for driving, a pump body connected to the motor, and a support structure arranged at the bottom of the pump body. A left support plate and a right support plate are extended on both sides of the support structure. A water channel structure is installed on the left support plate and the right support plate to connect to the inside of the pump body to cool the pump body; the water channel structure includes a water inlet channel arranged on the left support plate and a water outlet channel arranged on the right support plate.

[0004] However, the sealing effect of the screw pump in the prior art and the design of the threaded rod thereof are not significant when used in vacuum pumping technology. Summary of the invention

[0005] In view of the above problems in the prior art, an object of the present invention is to provide a screw pump for LNG ships.

[0006] The present invention provides the following technical solutions:

[0007] A screw pump for LNG ships comprises a pump body, a motor and a muffler mounted on the pump body, wherein the pump body comprises a rotor assembly, a shell sleeved outside the rotor assembly, a front cover assembly located at one end of the rotor assembly and mounted on the shell, a side cover assembly located at the other end of the rotor assembly and mounted on the shell, a rear cover mounted on the side cover assembly, and a bearing gland mounted on the front cover assembly, wherein the rotor assembly is sealed in the pump body by a lip seal in conjunction with a special mechanical seal to achieve gas-liquid sealing; the rotor assembly comprises a driving threaded rod and a driven threaded rod, the driving threaded rod and the driven threaded rod are connected and transmitted by gears, and the driving threaded rod and the driven threaded rod are meshed with each other, and the motor is mounted on the driving threaded rod.

[0008] Specifically, the front cover assembly includes a front cover, a rotor assembly movably mounted on the front cover through a bearing and a bearing seat, a lip seal assembly placed in the bearing seat and in contact with the rotor assembly, and an intake side sealing plate assembly mounted on the inner wall of the front cover and in contact with the rotor assembly.

[0009] Specifically, the intake side sealing plate assembly includes an intake side sealing plate installed on the front cover, a sealing ring sleeve placed in the intake side sealing plate and sleeved on the outside of the rotor assembly, the sealing ring sleeve is provided with a plurality of grooves, the sealing ring is placed in the grooves, and the sealing ring contacts the inner wall of the intake side sealing plate.

[0010] Specifically, the lip seal assembly is composed of two lip seals which are arranged back to back and in parallel. The lip seal is composed of an annular connector and a rubber ring. The rubber ring is arranged on the inner ring of the annular connector so that the rubber ring is tightly attached to the rotor assembly. The lip seal assembly cooperates with the intake side sealing plate assembly to form a lip seal.

[0011] Specifically, the annular connector is made of stainless steel, the rubber ring is made of silicone rubber, and the lip seal assembly forms a labyrinth seal.

[0012] Specifically, the side cover assembly includes a side cover, a rotor assembly installed on the side cover through bearing 2, a moving ring installed on the rotor assembly, and the moving ring rotates with the rotation of the rotor assembly, an intake side sealing plate assembly installed on the inner wall of the side cover and in contact with the rotor assembly, a static ring sleeve installed on the intake side sealing plate, the static ring is placed in the static ring sleeve, and a rubber ring is placed between the static ring and the static ring sleeve, and a corrugated ring is provided between the static ring and the static ring sleeve, and the corrugated ring presses the static ring tightly in the static ring sleeve, so that the static ring does not rotate with the rotation of the rotor assembly; the static ring sleeve, static ring, corrugated ring, rubber ring and intake side sealing plate assembly cooperate with each other to form a special mechanical seal.

[0013] Specifically, the pitch on the rotor assembly includes equal pitch, gradual pitch and variable pitch, the equal pitch is the first pitch close to one end of the side cover assembly; the variable pitch is the last pitch close to one end of the front cover assembly; the pitch is gradual between the equal pitch and the variable pitch; the number of the gradual pitch is n, the pitch of the equal pitch is a (mm), the pitch of the variable pitch is b (mm), then the pitch of the gradual pitch is:

[0014]

[0015] Specifically, the spiral line type of the rotor assembly is a rotor line matching sharp corner grinding type.

[0016] Specifically, the cycloid satisfies the cycloid segment equation:

[0017] r 11 =[R F ,R A ],

[0018]

[0019] The parameters in the cycloid segment equation are defined as:

[0020] r 11——the length of the radial vector of a point on the cycloid;

[0021] θ 11 — the polar angle of a point on the cycloid;

[0022] R F =d2——tooth root circle radius; d——tooth root circle diameter;

[0023] R A =D2——tooth tip circle radius; D——tooth tip circle diameter;

[0024] R E =e2=(R A +R F )2——pitch circle radius; e——pitch circle diameter, axis spacing;

[0025] The root circle satisfies the root circle segment equation:

[0026] r 22 =R F ,

[0027] θ 22 =[0,η S ]

[0028] η s =θ 2s +β m1 =θ 2s -θ 2m +π

[0029]

[0030] The parameters in the tooth root circle equation are defined as:

[0031] r 22 ——radial length of a point on the tooth root circle;

[0032] θ 22 ——polar angle of a point on the tooth root circle;

[0033] R0——base circle radius;

[0034] θ 2s ——polar angle of the starting point of the tooth root circle;

[0035] θ 2m ——phase polar angle of tooth root circle;

[0036] β m1 ——initial phase angle of tooth root circle;

[0037] The involute satisfies the involute segment equation:

[0038] r3=[R F ,RA ],

[0039]

[0040] Among them, the initial phase angle of the involute The first rotation form of the involute line equation, point (r3,θ3) is on the positive X axis, polar coordinate form: Therefore:

[0041] The parameters in the involute segment equation are defined as:

[0042] r3——the length of the radius vector at a point on the involute;

[0043] θ3——polar angle of a point on the involute,

[0044] ——the development angle of a point on a segment of an involute;

[0045] β m ——initial phase angle of involute;

[0046] ——the development angle of a point on the other segment of the involute;

[0047] The addendum circle satisfies the addendum circle segment equation:

[0048] r 44 =R A ,

[0049] θ 44 =[η e ,2π]

[0050] The parameters

[0051] η e =θ 4e +β m =θ 4e -θ 4m +π

[0052]

[0053] The parameters in the involute segment equation are defined as:

[0054] r 44 ——radial length of a point on the tooth tip circle;

[0055] θ 44 ——polar angle of a point on the tooth addendum circle;

[0056] θ 4e ——polar angle of the end point of the addendum circle;

[0057] θ 4m ——Phase polar angle of tooth addendum circle.

[0058] The beneficial effects of the present invention are:

[0059] 1. The rotor assembly in this device is sealed in the pump body by lip seal and special mechanical seal to achieve gas-liquid sealing, with better sealing effect;

[0060] 2. In this device, the pitch and spiral line shape of the threaded rod are designed, thereby improving the vacuum extraction efficiency of the screw pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0062] Figure 1 is a three-dimensional diagram of the present invention;

[0063] Figure 2 is a top view of the pump body of the present invention;

[0064] Figure 3 yes Figure 2 Cross-sectional view at AA in the middle;

[0065] Figure 4 is a three-dimensional diagram of the air intake side sealing plate assembly of the present invention;

[0066] Figure 5 is a three-dimensional diagram of the sealing ring sleeve in the present invention;

[0067] Figure 6 is a three-dimensional diagram of the lip seal assembly of the present invention;

[0068] Figure 7 It is a structural schematic diagram of the side cover assembly in the present invention;

[0069] Figure 8 It is a schematic diagram of the structure of the stationary ring and the corrugated ring in the present invention;

[0070] Fig. 9 is a schematic diagram of the pitch on the rotor assembly of the present invention;

[0071] Fig.10 is a schematic diagram of a spiral line on a rotor assembly in the present invention;

[0072] The markings in the figure are: 1, pump body; 2, motor; 3, muffler; 4, cycloid; 5, root circle; 6, addendum circle; 7, involute;

[0073] 101, rear cover; 102, housing; 103, side cover assembly; 104, rotor assembly; 105, bearing gland; 106, front cover assembly;

[0074] 1031, side cover; 1032, bearing 2; 1033, dynamic ring; 1034, corrugated ring; 1035, static ring sleeve; 1036, static ring;

[0075] 1041, a moving threaded rod; 1042, a driven threaded rod;

[0076] 1061, front cover; 1062, lip seal assembly; 1063, bearing 1; 1064, air intake side sealing plate assembly; 1065, bearing seat;

[0077] 10621, lip seal; 10622, annular connector; 10623, rubber ring;

[0078] 10641. Inlet side sealing plate; 10642. Sealing ring sleeve; 10643. Groove. DETAILED DESCRIPTION

[0079] Embodiment 1

[0080] like Figure 1 As shown, the present invention provides an LNG marine screw pump, comprising a pump body 1, a motor 2 and a muffler 3 installed on the pump body 1.

[0081] Please focus on Figure 2 and Figure 3 The pump body 1 includes a rotor assembly 104, a shell 102 sleeved outside the rotor assembly 104, a front cover assembly 106 located at one end of the rotor assembly 104 and installed on the shell 102, a side cover assembly 103 located at the other end of the rotor assembly 104 and installed on the shell 102, a rear cover 101 installed on the side cover assembly 103, and a bearing cover 105 installed on the front cover assembly 106.

[0082] The rotor assembly 104 is sealed in the pump body 1 by a lip seal and a special mechanical seal to achieve gas-liquid sealing.

[0083] The rotor assembly 104 includes a driving threaded rod 1041 and a driven threaded rod 1042 . The driving threaded rod 1041 and the driven threaded rod 1042 are connected and transmitted via gears. The driving threaded rod 1041 and the driven threaded rod 1042 are meshed with each other. The motor 2 is mounted on the driving threaded rod 1041 .

[0084] The front cover assembly 106 includes a front cover 1061, a rotor assembly 104 movably mounted on the front cover 1061 through a bearing 1063 and a bearing seat 1065, a lip seal assembly 1062 placed in the bearing seat 1065 and in contact with the rotor assembly 104, and an intake side sealing plate assembly 1064 mounted on the inner wall of the front cover 1061 and in contact with the rotor assembly 104.

[0085] Please focus on Figure 4 and Figure 5 The air intake side sealing plate assembly 1064 includes an air intake side sealing plate 10641 installed on the front cover 1061, a sealing ring sleeve 10642 placed in the air intake side sealing plate 10641 and sleeved on the outside of the rotor assembly 104, and a plurality of grooves 10643 are provided on the sealing ring sleeve 10642, and the sealing ring is placed in the groove 10643, and the sealing ring is in contact with the inner wall of the air intake side sealing plate 10641.

[0086] Please focus on Figure 6 The lip seal assembly 1062 is composed of two lip seals 10621 that are arranged in parallel and back to back. The lip seal 10621 is composed of an annular connector 10622 and a rubber ring 10623. The rubber ring 10623 is arranged on the inner ring of the annular connector 10622, so that the rubber ring 10623 is tightly attached to the rotor assembly 104.

[0087] Specifically, the annular connector 10622 is made of stainless steel, the rubber ring 10623 is made of silicone, and the lip seal assembly 1062 forms a labyrinth seal, thereby ensuring the sealing performance inside the pump body 1 to the greatest extent.

[0088] Please focus on Figure 7 and Figure 8 The side cover assembly 103 includes a side cover 1031, a rotor assembly 104 is mounted on the side cover 1031 through a bearing 1032, a moving ring 1033 mounted on the rotor assembly 104, and the moving ring 1033 rotates with the rotation of the rotor assembly 104, an intake side sealing plate assembly 1064 mounted on the inner wall of the side cover 1031 and in contact with the rotor assembly 104, a static ring sleeve 1035 is mounted on the intake side sealing plate 10641, a static ring 1036 is placed in the static ring sleeve 1035, and a rubber ring is placed between the static ring 1036 and the static ring sleeve 1035, and a corrugated ring 1034 is provided between the static ring 1036 and the static ring sleeve 1035, and the corrugated ring 1034 presses the static ring 1036 against the static ring sleeve 1035, so that the static ring 1036 will not rotate with the rotation of the rotor assembly 104, thereby further ensuring the sealing inside the pump body 1.

[0089] The lip seal assembly 1062 in the present device cooperates with the air intake side sealing plate assembly 1064 to form a lip seal; and the static ring sleeve 1035, static ring 1036, corrugated ring 1034, rubber ring and air intake side sealing plate assembly 1064 cooperate with each other to form a special mechanical seal; compared with the commonly used dynamic ring to form a seal in the prior art, the special mechanical seal of the present device has a more significant sealing effect.

[0090] Embodiment 2

[0091] like Fig. 9 As shown, the LNG marine screw pump disclosed in the second embodiment includes a different pitch design, while other devices, installation positions, and usage methods are the same as those of the first embodiment.

[0092] The pitch on the rotor assembly 104 includes equal pitch, gradual pitch and variable pitch, wherein the equal pitch is the first pitch close to one end of the side cover assembly 103; the variable pitch is the last pitch close to one end of the front cover assembly 106; the pitch is gradual between the equal pitch and the variable pitch; the number of the gradual pitch is n, the pitch of the equal pitch is a (mm), the pitch of the variable pitch is b (mm), and therefore the pitch of the gradual pitch is:

[0093]

[0094] Under the above pitch design, compared with the equal pitch design in the prior art, the pumping efficiency is better under the pitch design of the device.

[0095] Embodiment 3

[0096] like Fig.10 As shown, the LNG marine screw pump disclosed in the third embodiment is the same as that in the first embodiment except that the screw type design is different, while the other devices, installation positions, and usage methods are the same as those in the first embodiment.

[0097] The screw shape of the rotor assembly 104 of the device is a rotor profile with a sharp corner grinding shape, that is, a combination of a cycloid 4 , a tooth root circle 5 , an involute 6 and a tooth top circle 7 .

[0098] The cycloid 4 satisfies the cycloid segment equation:

[0099] r 11 =[R F ,R A ],

[0100]

[0101] The parameters in the cycloid segment equation are defined as:

[0102] r 11 ——the length of the radial vector of a point on the cycloid;

[0103] θ11 — the polar angle of a point on the cycloid;

[0104] R F =d2——tooth root circle radius; d——tooth root circle diameter;

[0105] R A =D2——tooth tip circle radius; D——tooth tip circle diameter;

[0106] R E =e2=(R A +R F )2——pitch circle radius; e——pitch circle diameter, axis spacing. The root circle 5 satisfies the root circle segment equation:

[0107] r 22 =R F ,

[0108] θ 22 =[0,η S ]

[0109] η s =θ 2s +β m1 =θ 2s -θ 2m +π

[0110]

[0111] The parameters in the tooth root circle equation are defined as:

[0112] r 22 ——radial length of a point on the tooth root circle;

[0113] θ 22 ——polar angle of a point on the tooth root circle;

[0114] R0——base circle radius;

[0115] θ 2s ——polar angle of the starting point of the tooth root circle;

[0116] θ 2m ——phase polar angle of tooth root circle;

[0117] β m1 ——The initial phase angle of the tooth root circle.

[0118] The involute 6 satisfies the involute segment equation:

[0119] r3=[R F ,R A ],

[0120]

[0121] Among them, the initial phase angle of the involute The first rotation form of the involute line equation, point (r3,θ3) is on the positive X axis, polar coordinate form: Therefore:

[0122] The parameters in the involute segment equation are defined as:

[0123] r3——the length of the radius vector at a point on the involute;

[0124] θ3——polar angle of a point on the involute,

[0125] ——the development angle of a point on a segment of an involute;

[0126] β m ——initial phase angle of involute;

[0127] ——The development angle of a point on the other segment of the involute.

[0128] The tooth tip circle 7 satisfies the tooth tip circle segment equation:

[0129] r 44 =R A ,

[0130] θ 44 =[η e ,2π]

[0131] The parameters

[0132] η e =θ 4e +β m =θ 4e -θ 4m +π

[0133]

[0134] The parameters in the involute segment equation are defined as:

[0135] r 44 ——radial length of a point on the tooth tip circle;

[0136] θ 44 ——polar angle of a point on the tooth addendum circle;

[0137] θ 4e ——polar angle of the end point of the addendum circle;

[0138] θ 4m ——Phase polar angle of tooth addendum circle.

[0139] Under the design of the screw type and the screw pitch, compared with the screw type design of the prior art, the vacuuming efficiency is better under the screw type design of the device.

[0140] Specifically, after the change, the air extraction rate is increased from the original 1080m 3 / h increased to 1250m 3 / h. The pump chamber temperature was reduced from the original maximum of 200 degrees Celsius to 150 degrees Celsius, and the noise was reduced from the original 80 decibels to below 70 decibels.

[0141] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A LNG marine screw pump, comprising a pump body (1), a motor (2) mounted on the pump body (1) and a muffler (3), It is characterized in that The pump body (1) comprises a rotor assembly (104), a housing (102) sleeved outside the rotor assembly (104), a front cover assembly (106) located at one end of the rotor assembly (104) and mounted on the housing (102), a side cover assembly (103) located at the other end of the rotor assembly (104) and mounted on the housing (102), a rear cover (101) mounted on the side cover assembly (103), and a bearing gland (105) mounted on the front cover assembly (106), wherein the rotor assembly (104) is sealed in the pump body (1) by a lip seal in conjunction with a special mechanical seal to achieve gas-liquid sealing; the rotor assembly (104) comprises a driving threaded rod (1041) and a driven threaded rod (1042), the driving threaded rod (1041) and the driven threaded rod (1042) being connected and driven by gears, and the driving threaded rod (1041) and the driven threaded rod (1042) are meshed with each other, and the motor (2) is mounted on the driving threaded rod (1041); The helical line shape of the rotor assembly (104) is a combination of a cycloid (4), a tooth root circle (5), an involute (6) and a tooth top circle (7); The cycloid (4) satisfies the cycloid segment equation: , The parameters in the cycloid segment equation are defined as: ——the length of the radial vector of a point on the cycloid; — the polar angle of a point on the cycloid; ——tooth root circle radius; ——tooth root diameter; ——tooth tip circle radius; ——tooth tip diameter; ——pitch circle radius; ——pitch diameter, axis spacing; The root circle (5) satisfies the root circle segment equation: , The parameters in the tooth root circle equation are defined as: ——radial length of a point on the tooth root circle; ——polar angle of a point on the tooth root circle; ——base circle radius; ——polar angle of the starting point of the tooth root circle; ——phase polar angle of tooth root circle; ——initial phase angle of tooth root circle; The involute (6) satisfies the involute segment equation: ， Among them, the initial phase angle of the involute The first rotation form of the involute line equation, point On the positive X axis, Polar coordinate form: Therefore: The parameters in the involute segment equation are defined as: ——the length of the radius vector at a point on the involute; — the polar angle of a point on the involute, ; ——the development angle of a point on a segment of an involute; ——initial phase angle of involute; ——the development angle of a point on the other segment of the involute; The tooth addendum circle (7) satisfies the tooth addendum circle segment equation: , The parameters The parameters in the involute segment equation are defined as: ——radial length of a point on the tooth tip circle; ——polar angle of a point on the tooth addendum circle; ——polar angle of the end point of the addendum circle; ——Phase polar angle of tooth addendum circle.

2. The LNG marine screw pump according to claim 1, characterized in that: The front cover assembly (106) comprises a front cover (1061), a rotor assembly (104) movably mounted on the front cover (1061) through a bearing 1 (1063) and a bearing seat (1065), a lip seal assembly (1062) disposed in the bearing seat (1065) and in contact with the rotor assembly (104), and an intake side sealing plate assembly (1064) mounted on the inner wall of the front cover (1061) and in contact with the rotor assembly (104).

3. The LNG marine screw pump according to claim 2, characterized in that: The air intake side sealing plate assembly (1064) comprises an air intake side sealing plate (10641) mounted on the front cover (1061), a sealing ring sleeve (10642) disposed in the air intake side sealing plate (10641) and sleeved on the outside of the rotor assembly (104), wherein the sealing ring sleeve (10642) is provided with a plurality of grooves (10643), a sealing ring is disposed in the groove (10643), and the sealing ring is in contact with the inner wall of the air intake side sealing plate (10641).

4. The LNG marine screw pump according to claim 3, characterized in that: The lip seal assembly (1062) is composed of two lip seals (10621) arranged in parallel and facing each other, wherein the lip seal (10621) is composed of an annular connecting piece (10622) and a rubber ring (10623), wherein the rubber ring (10623) is arranged on the inner ring of the annular connecting piece (10622), so that the rubber ring (10623) is in close contact with the rotor assembly (104); the lip seal assembly (1062) cooperates with the air intake side sealing plate assembly (1064) to form a lip seal.

5. The LNG marine screw pump according to claim 4, characterized in that: The annular connector (10622) is made of stainless steel, the rubber ring (10623) is made of silicone rubber, and the lip seal assembly (1062) forms a labyrinth seal.

6. The LNG marine screw pump according to claim 3, characterized in that: The side cover assembly (103) comprises a side cover (1031), a rotor assembly (104) mounted on the side cover (1031) via a second bearing (1032), a moving ring (1033) mounted on the rotor assembly (104), the moving ring (1033) rotating with the rotation of the rotor assembly (104), an air intake side sealing plate assembly (1064) mounted on the inner wall of the side cover (1031) and in contact with the rotor assembly (104), a stationary ring sleeve (1035) mounted on the air intake side sealing plate (10641), and a stationary ring (1036) disposed on the stationary ring sleeve (103 5), a rubber ring is placed between the static ring (1036) and the static ring sleeve (1035), and a corrugated ring (1034) is provided between the static ring (1036) and the static ring sleeve (1035), and the corrugated ring (1034) presses the static ring (1036) tightly against the static ring sleeve (1035), so that the static ring (1036) does not rotate with the rotation of the rotor assembly (104); the static ring sleeve (1035), the static ring (1036), the corrugated ring (1034), the rubber ring and the air intake side sealing plate assembly (1064) cooperate with each other to form a special mechanical seal.

7. The LNG marine screw pump according to claim 1, characterized in that: The pitches on the rotor assembly (104) include equal pitch, gradual pitch and variable pitch, wherein the equal pitch is the first pitch close to one end of the side cover assembly (103); the variable pitch is the last pitch close to one end of the front cover assembly (106); the pitches between the equal pitch and the variable pitch are gradual pitches; the number of gradual pitches is n, the pitch of the equal pitch is a, the pitch of the variable pitch is b, and the pitch of the gradual pitch is: 。

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