JPH0617023Y2 - Rotary pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a rotary pump having a mechanical seal interposed between a rotor drive shaft and a casing, particularly a rotary pump used for transporting foods and drugs. Related to the improvement of.

(Prior Art and Problems Thereof) In the rotary pump in which the mechanical seal is interposed between the rotor drive shaft and the casing as described above,
A coil spring is used to press the rotary ring that rotates integrally with the rotor drive shaft of the mechanical seal and the casing-side fixed ring into pressure contact with each other in the axial direction. Generally, both ends of the coil spring used in a compressed state have an appropriate length. An eccentric plane was formed in the salient portion so as to make surface contact with the surface that receives the end of the spring. When such a conventional general coil spring is used for the mechanical seal of the rotary pump, both ends of the coil spring are in surface contact with, for example, the rotor and the rotating ring, so that the stability of the spring is increased. However, there were the following problems.

That is, the transport liquid that has flowed into the internal cavity of the mechanical seal through the gap between the rotor and the casing enters the surface contact portion between the surface that receives the end portion of the coil spring and the end flat surface of the spring. , Will stay. Especially when the transportation liquid is food, even if a small amount of the accumulated food is putrefused or deteriorated, it may adversely affect the food transported thereafter. At the end of the procedure, it was obliged to completely disassemble the pump and clean the inside of the pump. However, disassembling and cleaning such a pump and assembling work after cleaning require a great deal of labor and time, resulting in an increase in product cost.

(Means for Solving Problems) The present invention proposes a rotary pump capable of solving the above-mentioned conventional problems, which is characterized in that a rotary pump is provided between a rotor drive shaft and a casing. A rotary pump having a mechanical seal including a casing-side fixed ring, a rotary ring that rotates integrally with a rotor drive shaft, and a coil spring that axially urges one of the rings toward the other ring. A portion of the coil spring that abuts on the spring end receiving surface at both ends has a chevron cross-sectional shape that forms a sharp ridge line contacting the spring end receiving surface. An annular recessed groove is formed on the step surface of the rotating ring, which is one of the spring end receiving surfaces, which is one of the abutting spring end receiving surfaces. There is a point.

(Embodiment) An embodiment of the present invention will be described below with reference to the attached exemplary drawings.

In FIGS. 1 and 2, 1A and 1B are rotor drive shafts driven by a motor (not shown), and rotors 3A and 3B are spline-fitted to the spline shaft portion 2 near the tip thereof, respectively. Rotor fixing nuts 5 are screwed and fastened to the tip screw shaft portions 4, respectively. Reference numeral 6 denotes a casing, and a casing main body 11 having a suction pipe connecting portion 9 and a discharge pipe connecting portion 10 of a pump chamber 8 in which the pump tooth portions 7 of the rotors 3A and 3B are loosely fitted and rotated, and a casing main body 11 The casing cover 12 covers the protruding rotors 3A and 3B and the nut 5.

Between the casing body 6 and the rotor drive shafts 1A and 1B, a mechanical seal 13 for preventing leakage of the transport liquid and a mechanical seal 14 for preventing leakage of sterilizing steam are interposed. . The mechanical seal 13 includes a fixed ring 15 fixed to the casing body 11, a rotary ring 17 axially movably coupled to the boss portion 16 of the rotors 3A and 3B, and the rotary ring 17 and the rotors 3A and 3B. It is composed of a coil spring 18 interposed between the fixed ring 15 and the casing main body 11, and is interposed between the fixed ring 15 and the casing body 11, and between the fixed ring 15 and the rotor drive shafts 1A and 1B. O-rings 19 and 20 as liquid-sealing rings are respectively interposed between and.

21a and 21b are both mechanical seals 13 and 14
It is a steam supply / discharge passage provided in the casing body 11 in order to circulate sterilizing steam into a space 22 formed between the rotor drive shafts 1A, 1B and the casing body 11. Reference numeral 23 denotes an annular passage formed in the end surface of the casing body 11 so as to surround the pump chamber 8,
Steam supply / discharge passages 24a, 24b for circulating the sterilizing steam in the annular passage 23 are provided in the casing body 11.
The casing cover 12 is internally and externally double sealed so as to sandwich a portion facing the annular passage 23.
Rings 25 and 26 are fitted.

The mechanical seal 13 will be described with reference to FIGS. 3 and 4.
In more detail, the fixing ring 15 is made of a cemented carbide sealing material such as ceramic, and the casing body 1
It has a notch recess 28 into which the whirl-stop pin 27 protruding from the first fixing ring receiving portion 11a is fitted. Also, the O
The ring 19 is fitted in an annular groove 29 formed on the inner peripheral surface of the casing body 11, and is pressed against the bottom surface of the annular groove 29 and the central portion of the outer peripheral surface of the fixed ring 15. Then, from the center of the outer peripheral surface where the O-ring 19 is in pressure contact, the rotary ring 1
The outer peripheral surface 15a of the fixing ring 7 on the 7 side is tapered so that the diameter becomes smaller toward the tip side.
The inner diameter of the casing main body portion 11b facing 5a and forming the annular groove 29 is configured to be as large as possible, and a relatively wide annular flow passage 30 is formed therebetween.

A seal ring 31 made of tungsten carbide or the like and slidably in contact with the end surface of the fixed ring 15 is fitted in and fixed to the rotary ring 17.
An annular groove 32 in which the O-ring 20 is loosely fitted is formed on the inner side of. A small-diameter protrusion 17b is provided so as to form a step surface 17a for receiving the coil spring 18. The small-diameter protrusion 17b has a low turbos portion 1
6 is provided with a cutout recess 34 into which the whirl-stop pin 33 is fitted, and is integrated with the low turbos portion 16 in a state where the rotating ring 17 can move axially within a certain range with respect to the low turbos portion 16. It is configured to rotate.

Further, the coil spring 18 is connected to the rotating ring 17 so as to communicate with the rotor side end of the annular groove 32.
Radial through-flow passages 35 extending in the axial direction on both sides of the receiving step surface 17a are provided at two locations in the diametrical direction, and at the corners between the step surface 17a and the small-diameter protruding portion 17b. An annular recessed groove 36 that is continuous over the entire circumference is provided.

The coil spring 18 is shown in FIGS. 3 and 5 to 7.
As shown in the figure, the rotor end surface 3a and the rotating ring 17 are
Area portion 37 that may be in pressure contact with the step surface 17a, for example, the area portion 3 that extends from both ends 18a to approximately 270 degrees.
The wire 38 of No. 7 is processed so that the side facing the rotor end surface 3a and the step surface 17a of the rotating ring 17 has a chevron cross section. Therefore, this coil spring 18
Is the rotor end surface 3a and the step surface 17a of the rotating ring 17.
On the other hand, line contact is made at the sharp ridge line 18b.

Incidentally, as shown in FIGS. 1 to 3, a cylindrical protruding portion 11c of the casing body 11 forming the inner peripheral wall of the pump chamber 8.
A communication passage 40 that connects the vicinity of the high-pressure discharge portion in the pump chamber 8 and the hollow portion 39 that houses the mechanical seal 13 to each other.
Is provided. In FIG. 2, reference numeral 41 is an inlet, and 42 is an outlet.

In the rotary pump configured as described above, both rotors 3A, 3B are driven by both rotor drive shafts 1A, 1B.
2 are synchronized rotationally driven in opposite directions as indicated by arrows in FIG. 2, whereby the pump teeth 7 that rotate in the pump chamber 8 respectively act to suck the liquid into the pump chamber 8 from the suction port 41. At the same time, it is pressurized and sent out to the discharge port 42, but a part of the pressurized liquid flows from the communication passage 40 into the hollow portion 39 that houses the mechanical seal 13, and flows inside the hollow portion 39. After that, through the gap between the casing body 11 and the rotors 3A and 3B, the gas flows out to the low pressure side of the pump chamber 8, that is, to a portion near the suction port 41. That is, a part of the liquid pressurized via the pump chamber 8 circulates and flows to the suction port 41 side via the cavity 39.

On the other hand, the rotary ring 17 of the mechanical seal 13 is fixed by the biasing force of the coil spring 18 while rotating integrally with the rotor drive shafts 1A and 1B and the rotor turbos portion 16 via the rotation stop pin 33 and the notch recess 34. 15
Since the fixed ring 15 and the rotating ring 17 (seal ring 31) are pressed toward each other, the fixed ring 15 and the rotating ring 17 (seal ring 31) come into sliding contact with each other in a pressed state to prevent the liquid from flowing between the two rings. or,
A rotary ring 17 is liquid-sealed between the fixed ring 15 and the casing body 11 by an O-ring 19 and rotates integrally with each other.
A liquid seal is provided between the rotor drive shaft 1A and the rotor drive shaft 1B by an O-ring 20.

Therefore, the liquid that has flowed into the cavity 39 as described above flows out between the casing main body 11 and the rotor drive shafts 1A and 1B so that the mechanical seal 13 and the O
Although the liquid is completely sealed by the rings 19 and 20, the liquid that has flowed into the hollow portion 39 passes through the through flow path 35 and becomes O.
It flows in the annular groove 32 on the cavity 39 side of the ring 20 and in the gaps between the rotary ring 17 and the rotor drive shafts 1A, 1B and the rotor turbos portion 16. Further, the liquid flowing into the cavity 39 can easily flow in the annular groove 29 on the cavity 39 side of the O-ring 19 due to the existence of the wide annular channel 30.

Further, since the rotor end surface 3a and the rotating ring step surface 17a and the coil spring 18 are only in line contact with each other at the sharp ridge line 18b of the spring 18, the rotor end surface 3a and the rotating ring step surface 17a are in contact with each other. The liquid comes into contact with and flows over substantially the entire surface. Also, the rotary ring step surface 1 in a state of being covered by the coil spring 18
Since the entrance corner between 7a and the small-diameter protrusion 17b is wide due to the existence of the annular recessed groove 36, the liquid can easily flow also in this entrance corner.

That is, the transport liquid that has flowed into the cavity 39 that houses the mechanical seal 13 is transferred into the O-ring annular groove 32 inside the rotating ring 17, the rotating ring 17, the rotor drive shafts 1A and 1B, and the rotor turbos portion 16. Between them, inside the O-ring annular groove 29 outside the fixed ring 15, the coil spring 18, the rotor end surface 3a, and the rotary ring step surface 17
There is no fear that it will enter the corners or the like between the contact surfaces with a or between the rotary ring step surface 17a and the small diameter protruding portion 17b and stay there. Therefore, after the liquid transportation work by the rotary pump is completed, for example, when the cleaning liquid is replaced with the transportation liquid and pressure-fed by the rotary pump, the cleaning water flowing in the pump flows into the hollow portion 39 as described above. , The O-rings 19 and 20, and the rotor end surface 3a and the rotating ring step surface 17a with which the ends of the coil springs 18 come into contact and flow to substantially the entire surfaces thereof, and the cavity 39 You can surely clean every corner inside.

In the embodiment, the rotary ring 17 is connected to the rotor drive shaft 1A,
1B (rotor turbos portion 16) is movably coupled in the axial direction, and this rotating ring 17 is configured to be pressed and biased by the coil spring 18 toward the fixed ring 15. The rotating ring 17 has a rotor drive shaft 1A. , 1B (rotor turbos portion 16), the fixing ring 15 is movably coupled to the casing body 11 in the axial direction of the rotor drive shafts 1A, 1B, and the fixing ring 15 is rotated toward the rotating ring 17 by a coil spring. You may comprise so that it may be pressed and biased.

(Operation and Effect of the Invention) According to the rotary pump of the present invention as in the above embodiment, the coil spring that presses the fixed ring and the rotary ring of the mechanical seal interposed between the casing and the rotor drive shaft. Is a spring end receiving surface (in the embodiment, the rotor end surface 3a and the rotating ring step surface 1).
Since it comes into line contact with 7a) at a sharp ridge, the liquid that has flowed into the internal cavity of the mechanical seal enters between the contact surface between the end of the coil spring and the spring receiving surface as in the conventional case. There is no fear of staying in. Moreover, compared with the case of using a coil spring with a circular cross-section material as it is, the corners on both sides of the line contact point with the spring receiving surface are wide open obtusely, so as described above When washing water is circulated in the pump by operating the pump, the corners on both sides of the line contact point can be completely washed with the washing water, and it is necessary to disassemble and wash the pump as in the past. Disappears. Moreover, since the annular recessed groove is formed on the step surface of the rotating ring, which is one of the spring end receiving surfaces, of the both spring end receiving surfaces with which both ends of the coil spring abut, the vicinity of the step surface is formed. The liquid circulation area becomes wider, the liquid can easily flow, and a further cleaning action can be exhibited. Therefore, the labor and time for maintaining the inside of the pump for cleaning can be significantly reduced, and the cost of the product can be reduced.

The structure of the present invention is further effective by using the communication passage 40 for positively flowing a part of the pressurized liquid into the mechanical seal internal cavity 39 as described in the embodiment. Can be magnified.

[Brief description of drawings]

1 is a vertical side view, FIG. 2 is a vertical front view at a boundary between a casing body and a casing cover, and FIG. 3 is an enlarged vertical side view showing a mechanical seal portion for preventing transport liquid leakage in detail. FIG. 5 is a perspective view showing a fixed ring and a rotary ring of the mechanical seal, FIG. 5 is a perspective view of one end of the coil spring for mechanical seal, FIG. 6 is a front view of the spring, and FIG. It is an expanded sectional view of an important section. 1A, 1B ... Rotor drive shaft, 2 ... Spline shaft part, 3
A, 3B ... rotor, 5 ... rotor fixing nut, 6 ...
Casing, 7 ... Pump teeth, 8 ... Pump chamber, 11 ... Casing body, 12 ... Casing cover, 13 ... Mechanical seal for preventing leakage of transport liquid, 14 ... Mechanical seal for preventing leakage of sterilizing steam, 15 ... Fixing ring ,
17 ... Rotating ring, 18 ... Coil spring, 18b ...
Sharp ridge lines, 19, 20 ... O-rings, 27, 33 ... Whirl-stop pins, 29, 32 ... Annular grooves, 31 ... Seal rings,
35 ... Through flow path, 36 ... Annular recessed groove, 39 ... Mechanical seal internal cavity, 40 ... Communication passage, 41 ... Suction port, 42
… Discharge port.

Claims (1)

[Scope of utility model registration request] 1. A fixed ring on the casing side, a rotary ring rotating integrally with the rotor drive shaft, and one of the two rings pressed axially to the other ring side between the rotor drive shaft and the casing. In a rotary pump having a mechanical seal composed of a urging coil spring, the sharp end portions of the coil spring, which contact the spring end receiving surface, are in line contact with the spring end receiving surface. An annular recessed groove is formed on the step surface of the rotating ring, which is one of the spring end receiving surfaces on which both ends of the coil spring abut, and which has a mountain-shaped cross section formed on the ridge line. It is a rotary pump.