JPH0223299A - Seal structure of pump - Google Patents

Abstract

PURPOSE:To improve the safety of a seal and miniaturize the form of a connection by nipping an annular closing member formed on one end with a tapered projecting outer surface portion for a seal to be put in intimate contact with a tapered inner surface formed on one inner peripheral edge of the connection. CONSTITUTION:The tapered outer surfaces of lip portions 68, 68 of a gasket 60a are formed at an angle theta1 which is smaller than an angle theta2 made by the tapered inner surfaces 76, 76 of a connection. When an axial fastening force acts on the connection, the gasket 60a has the lip portions 68, 68 elastically deformed by the angular difference theta2-theta1 and self-tightening seal face pressure due to the reaction of metal is obtained in the tapered inner surfaces 76, 76 so that the lip portions make intimate contact with the tapered inner surfaces 76, 76 formed on the inner peripheral edges. Further, when the internal pressure acts on the inner surface, a force applied to the inner surface of the gasket 60a is received by the tapered portions 76, 76, so that seal surface pressure is increased and a self-tightening structure can be provided by utilizing the pressure.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a pump seal structure that seals between each joint of a pump, and more specifically, to a seal structure between each joint of a canned motor pump. Regarding improvements.

[Conventional technology]

In general, a canned motor pump circulates and supplies a portion of pump handling liquid into a motor rotor chamber of a canned motor section to cool the motor section and lubricate the bearings.

That is, in the canned motor pump shown in FIG. 5, the pump section 10 and the motor section 12 are connected via an adapter 14 in order to thermally separate them. This adapter 14 is provided with a pressure equalizing hole 18 in order to prevent cavitation of the auxiliary impeller 16, and communicates the area where the pressure is increased by the main impeller 20 with the rotor chamber 22, thereby pressurizing the rotor chamber 22 side. In this case, since the pressure equalizing hole 18 is a small hole, the flow of liquid from the pump section 10 to the motor section is reduced, so that the bearing i1! In order to cool the motor, a heat exchanger 26 is provided on the outer peripheral wall of the stator assembly 24, and an auxiliary impeller 16 provided in the rotor chamber 22 is used to cool the liquid in the motor section 12. constitutes the circulatory system of

Therefore, the circulation of liquid within the motor section 12 is as follows. First, the liquid pressurized by the auxiliary impeller 16 is introduced into the built-in pipe 30 of the heat exchanger 26 via the first circulation tube 28, where it is cooled by cooling water, and then transferred to the second circulation tube 28. tube 3
2 and into the rotor chamber 22 via the rear bearing housing 34. In this manner, fluid supplied into the rotor chamber 22 through the rear bearing housing 34 flows through the gap between the stator assembly 38 of the stator assembly 24 and the rotor can 42 of the rotor assembly 40 while lubricating the rear bearing 36. Cool the motor. The liquid, whose temperature has increased by several degrees Celsius due to cooling of the motor, lubricates the front bearing 44, returns to the suction part of the auxiliary impeller 16, and repeats the circulation. Note that the cooling water introduced into the heat exchanger 26 flows through the circulation tube 28.3.
The stator assembly 24 is configured to cool the circulating fluid flowing through the stator assembly 2 and at the same time cool the motor by using the outer circumferential wall of the stator assembly 24 as a heat transfer surface.

In this case, the pump part 1 constituting the canned motor pump
0 and the motor section 12 are connected via an adapter 14, and one end of the motor section 12 is connected to the rear bearing housing 3.
Gaskets 48 and 50 are provided at these joints to prevent leakage of high-temperature, high-pressure handling fluids. These gaskets are mainly spiral gaskets and ring joints, which are easy to design because the minimum design tightening pressure and gasket coefficient of the gasket are determined together with the shape by JI S'PASME etc. Therefore, it was widely adopted.

[Problem to be solved by the invention]

However, with these conventional gaskets, the necessary surface pressure is applied to the gasket by tightening them in the axial direction with bolts, etc. Therefore, due to fluctuations in temperature and pressure, the surface pressure of the gasket decreases, causing leaks. ,
Alternatively, since the load on the bolts becomes excessive, the diameter or number of bolts must be increased, resulting in a larger flange diameter, which has the disadvantage of increasing thermal stress.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to form an internal taper at the inner circumferential edge between each joint of a pump, and to sandwich an annular closing member between the joints, the annular closing member having an external taper protrusion that joins to the internal taper. The object of the present invention is to provide a pump seal structure that can improve the safety of the seal and reduce the size of each joint.

[Means to solve the problem]

In order to achieve the above object, the seal structure of the pump according to the present invention consists of a pump part and a motor part, and a part of the handled liquid pressurized by the pump is transferred between a pair of rotor shaft bearings in the motor part and a stator. In a pump that has a circulation system for handling liquid that flows between the rotors and communicates with the back of the impeller of the pump section, a small amount of water is used to seal between the joints of the pump (both at the inner circumferential edge of one of the opposing joints). an inner taper formed in the
In this case, the annular closing member has an outer tapered protrusion formed on at least one end so as to be closely joined to the inner taper, and the annular closing member is sandwiched between the joint parts to seal the joint parts. It is preferable that one of the opposing inner circumferential edges of the parts is formed to have an inner surface tapered, and the annular closing member is integrally provided with an outer surface tapered protrusion on the other side of the joint part so as to be closely joined to the inner surface taper. It is.

Further, one of the opposing inner peripheral edges of the joint part is formed into a cylindrical hole, and the annular closing member is integrally provided with a protrusion part on the other side of the joint part to be inserted into the cylindrical hole. A seal groove having one side tapered may be provided on the outer periphery of the protrusion, and a backup ring having an inner circumferential edge formed with a taper that closely connects with the taper may be inserted into the seal groove together with the O-ring.

[Effect]

According to the sealing structure of the pump according to the present invention, a part of the handled liquid pressurized by the pump is passed through the heat exchanger to lubricate the rear bearing, and then flows through the gap between the stator can of the stator assembly and the rotor can of the rotor assembly. The motor is cooled down, the front bearing is lubricated, and the cycle is repeated by returning to the suction part of the auxiliary impeller. In this case, in the annular closing member held between each joint of the pump, the external tapered protrusion is pressed against the internal taper of the inner peripheral edge by the action of internal pressure from the handling liquid, and is closely joined to achieve a reliable seal.

〔Example〕

Next, the seal structure of the pump according to the present invention will be described in detail below with reference to the accompanying drawings. For convenience of explanation, parts that are the same as those of the conventional structure shown in FIG. 5 are given the same reference numerals, and detailed explanation thereof will be omitted.

FIG. 1 is a sectional view of a main part showing a first embodiment of a pump seal structure according to the present invention. That is, the present invention provides a pump (hereinafter referred to as a canned motor pump) using a pump section 10, a motor section 12, and an adapter 14 that connects them.
The joints of this canned motor pump are joined and sealed via gaskets to prevent leakage of the handled liquid.

That is, the sealing structure of the joint shown in the first embodiment,
The basic structure of the joint was filed by the applicant and was registered as Utility Model Registration No. 1410055 (Utility Model No. 14466, 1983).

The present invention utilizes the structure of the above-mentioned joints in the seal structure of each joint of a canned motor pump, in which an inner taper is formed at the 100-circle peripheral edge of the opposing joints, and the joints are closely joined to the inner taper. A sealing portion is constructed by sandwiching an annular closing member (hereinafter referred to as a gasket) 60 between the joint portions and having externally tapered protruding portions (hereinafter referred to as lip portions 68, 68) on both sides.

In FIG. 1, the canned motor pump has a motor section 12.
Connect both ends of the rear bearing housing 46 and adapter 14.
It consists of three joint parts: a joint part that connects with the pump part IO and a joint part that connects the pump part 10 with the adapter 14, and gaskets 60a, 60b, and 60c are held in these joint parts, respectively. This gasket 6o is made of a material that improves lubrication and sealing performance on the sealing surface, such as MoS2° graphite.
Gold, tl, zinc chromate, fluororesin, oils and fats such as vaseline, etc. are suitably used depending on the usage conditions. Also,
As shown in FIG. 2, a counterbore 72 is formed in the rear bearing housing 46, which is one of the opposing joints, for holding the outer periphery of the gas kerater 60a, and at the inner periphery of the opposing joint. An inner surface taper with an angle θ2 is formed. Furthermore, the rear bearing housing 46
A bearing 36 that supports the rotor shaft 74 is inserted and supported.

Further, the outer surface taper of the lip portion 68.68 of the gasket 60a shown in the second TyJ is formed at an angle θ, and the relationship with the angle θ2 of the inner surface taper 76.76 is θ2>θ. Furthermore, the angle range of θ2 is 10° to 35°
The angular difference between θ1 and θ2 is preferably selected within the range of 0.5° to 5°. However, this gasket 60
a indicates that when an axial tightening force is applied to the joint, the gasket 6
The lip portion 68.68 of 0a is elastically deformed in proportion to the angle difference θ2-θ, and has an inner surface taper 76.7 formed on the inner peripheral edge.
6, a self-sealing surface pressure due to the reaction force of the metal is obtained on the taper 76, 76, and when internal pressure acts on the inner surface, the force applied to the inner surface of the gasket 60a is received by the taper 76. The pressure is increasing, and the structure is self-locking using pressure. Note that this gasket and the gaskets 60b and eoc used in other joints have a similar sealing structure, so a detailed description thereof will be omitted.

Next, a second embodiment will be explained with reference to FIG. That is, in the second embodiment, an inner surface taper 78 having an angle θ2 is formed at the inner peripheral edge of one of the joint parts (the motor part), and an inner surface taper 78 having an angle θ2 is formed on the other joint part (the bearing housing 46) to closely join the inner peripheral edge to the inner peripheral edge. , the externally tapered lip portion 7 of
0 is integrally formed. It should be noted that the relationship between materials and the like is the same as in the first embodiment described above, so a description thereof will be omitted.

Next, a third embodiment will be described with reference to FIG. 4. That is, in the third embodiment, an O-ring and a backup ring are used together in the sealing structure as a seal structure, and this allows the sealing structure to be used in the first embodiment as described above. In the second embodiment, even if the surface pressure decreases due to the elongation of the bolts that fasten each joint, the sealing effect is not affected.

That is, a cylindrical hole 80 is formed in one of the joint parts (motor part 12).
A seal is provided in which a protrusion 82 that is fitted into the cylindrical hole 80 is integrally formed at a local joint (rear bearing housing 46), and one side of the protrusion 82 is tapered on the outer periphery. A groove (hereinafter referred to as 0-ring groove) 62 is provided,
A seal structure is constructed by inserting into this O-ring groove 62, together with an O-ring 66, a backup ring 64 whose inner circumferential edge has a taper that closely joins the taper.

When internal pressure acts on the seal structure constructed in this way, the backup ring 64 is pressed by this acting force. However, even if the gap between the joints changes due to temperature or pressure, the crushing margin of the O-ring does not change, and even if the internal pressure increases abnormally, the backup ring 64 and the O-ring groove 62
Since the tapers of the O-ring are closely connected to each other and move in the radial direction along the taper, there is no need to cut the O-ring due to protrusion, which is the case with conventional O-ring grooves, and the range of application to pressure increase has been expanded.

By adopting the seal structure of the present invention, the load W acting on the joint part is: Wmt '' H+ Hp m-02・P2πb +-G −m-P , (l) Wm
2 = π ・b-G −)' ,,
, (2) where G: seat diameter, P: pressure, b: effective width of gasket seat 2m; gasket coefficient, y: minimum design tightening pressure of gasket (tightening force for effective sealing). Since the seal structure is a self-tightening structure, m and y can be set to zero. Therefore, +1), (
From Formula 21, the seat diameter G becomes the inner diameter or a dimension close to the inner diameter, and AffiW acting on the joint can be reduced.

〔Effect of the invention〕

As is clear from the above-mentioned embodiments, the pump seal structure according to the present invention has an inner surface tapered at the inner circumferential edge of at least one of the opposing joints of the pump, and at least one end of the pump is closely joined to the inner peripheral edge of the pump. By configuring an annular closing member having an outer surface tapered protrusion to be sandwiched between the joint parts, the seat diameter of the seal part can be reduced, and the diameter of the bolt for fastening the joint parts can be reduced.

The number of bolts or bolt installation has a small pitch circle, which eliminates the impediments to achieving a smaller ribbon shape, eliminates leakage due to temperature and pressure fluctuations, and reduces visual inspection, maintenance, etc. It has the advantage of being easy to use. Furthermore, the grooves of conventional gaskets are not required and the shape is simplified, making molding easier, and the overall size can be reduced, resulting in lower production costs.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part showing a first embodiment of a seal structure for a pump according to the present invention, FIG. 2 is an enlarged cross-sectional view of a main part showing a seal structure at the joint on the rear bearing housing side of FIG. 3 is an enlarged cross-sectional view of the main parts showing a second embodiment of the seal structure at the rear bearing housing side joint in FIG. 1, and FIG. 4 is an enlarged sectional view of the seal structure at the rear bearing housing side joint in FIG. FIG. 5 is an enlarged cross-sectional view of a main part of the third embodiment, and FIG. 5 is a cross-sectional view of a main part of a conventional canned motor pump. 14. Adapter 16. ,,auxiliary impeller 1
8. Pressure equalization hole 20. ,,main impeller 22,
,,rotor chamber 24. ,, stator assembly 26,,
, heat exchanger 28, , first circulation tube 30, .
Vibrator 32, second circulation tube 34,...
f& part bear, ring housing 36, . 71 part bearing 38. ,,stator can 40,,,rotor assembly 42. ,,Rotor can 44,,,Front bearing 48.50. ,, gaskets 60a, 60b, 6
0c ,, Gasket 62,, O-ring groove 64
．． ,, back amp ring 66,,, OIJ 7g
88.70. , ,') 7g section 72,,,
Counterbore 74. ,,rotor shaft 76.7B, ,,
Inner taper 80. , , Cylindrical hole 82 , , Projection part 10 , , Pump part 12. ,, Canned motor part IG FIG, 3 FIG.

Claims (3)

[Claims] (1) Consisting of a pump section and a motor section, a part of the liquid that is pressurized by the pump flows through a pair of rotor shaft bearings in the motor section and between the stator and rotor, and communicates with the back of the impeller of the pump section. In a pump that constitutes a circulation system for handling liquid, the pump has an inner surface taper formed on the inner peripheral edge of at least one of the opposing joints to seal between each joint, and at least one end of the pump to be closely joined to the inner surface taper. an annular closure member having an outer surface tapered protrusion;
A sealing structure for a pump, characterized in that the annular closing member is held between the joint parts to seal the joint parts. (2) One of the opposing inner circumferential edges of the joint part is formed to have an internally tapered surface, and the annular closing member has an integrally tapered externally protruding part on the other side of the joint part so as to be closely joined to the internally tapered surface. A seal structure for a pump according to claim 1, wherein the seal structure is provided in a pump. (3) One opposing inner peripheral edge of the joint is formed into a cylindrical hole, and the annular closing member is integrally provided with a protrusion on the other side of the joint to fit into the cylindrical hole. A sealing groove having a tapered side on one side is provided on the outer periphery of the protruding portion, and a backup ring having an inner peripheral edge formed with a taper that closely connects with the taper is inserted into the sealing groove together with an O-ring. Seal structure of the pump according to item 1.