JPH0581567U - Cassette type double mechanical seal - Google Patents

Abstract

(57) [Summary] [Purpose] All components of the mechanical seal on the sealed space A side and the non-sealed space B side are integrated to facilitate assembly and disassembly. [Structure] A pair of rotating rings 120, 120 aligned in the axial direction
Are elastically urged in opposite directions by a spring 150 arranged therebetween, and two sets of mechanical seals 100A, 100B that abut against a pair of fixed rings 110, 110 arranged in the urging direction of each rotary ring 120 are provided. Having both the fixed rings 110, 11
0 are airtightly fitted to the inner peripheries of the pair of outer cases 160, 160, and the opposite ends 161 and 161 of both outer cases 160, 160 are connected by linking means 170.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention integrates a double mechanical seal that axially seals with two sets of mechanical seals arranged axially between the sealed space side and the anti-sealed space side.

[0002]

[Prior Art]

 2. Description of the Related Art Conventionally, as a shaft sealing device mounted on, for example, a submersible pump, as shown in FIG. 2, a space between an impeller-side space or a sealed space A and a motor-side space or an anti-sealed space B is arranged in an axial direction. There is a double mechanical seal that axially seals with a pair of mechanical seals 10A and 10B.

The fixed rings 11 of the mechanical seals 10A and 10B are fitted to the impeller-side housing 18A and the motor-side housing 18B via cup gaskets 12, respectively, and the rotary ring 13 is attached to the housings 18A and 18B. A coil spring 15 is supported on the outer peripheral surface of the shaft 19 penetrating the inner periphery of 18B via the bellows 14 made of an elastomer, which are axially opposed to each other, and compressed between the rotary rings 13 and 13. Are elastically urged in opposite directions in the axial direction, and slide-contact with the end faces of the respective fixed rings 11 with an appropriate surface pressure to form a sealed sliding surface S. Each of the bellows 14 has an inner diameter cylindrical portion 14a having an appropriate tightening margin with respect to the outer peripheral surface of the shaft 19 by the drive ring 16, and the end portion 14b on the rotary ring 13 side is rotated by the case 17 respectively. The ring 17 is pressure-bonded to the back surface of the ring 13. The case 17 and the drive ring 16 engage with each other in the circumferential direction, so that the rotary ring 13 rotates integrally with the shaft 19.

[0004]

[Problems to be solved by the device]

 However, when the double mechanical seal having the above-mentioned conventional structure is to be incorporated into equipment such as a pump, the respective components constituting both mechanical seals 10A and 10B must be sequentially fitted according to a predetermined procedure. Not only was the mounting work complicated, but the management of each part when not mounted was also complicated. In addition, when the end faces of the fixed ring 1 and the rotary ring 3 that are the sliding surfaces S are damaged during the management when not mounted and during the above-mentioned assembling, the sealing performance will be greatly impaired, so be careful. I have to.

The present invention has been made in view of the above problems, and an object of the present invention is to integrate the respective parts of the double mechanical seal to facilitate assembly and disassembly.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a pair of axially arranged rotary rings that are elastically biased in opposite directions by springs arranged between the two rotary rings so as to bias each rotary ring. In a double mechanical seal having two sets of mechanical seals that abut against a pair of fixed rings arranged in the same direction, the two fixed rings are hermetically fitted to the inner circumferences of the pair of outer cases, respectively. It is intended to provide a cassette type double mechanical seal in which opposite ends of the two are joined by linking means. In this case, it is more preferable that both rotary rings are biased by the springs through the inner cases, and the opposite ends of the both inner cases abut each other.

[0007]

[Action]

 According to the above configuration, by connecting both outer cases with the link means, all the constituent parts of both mechanical seals can be integrated, and management in an unattached state to the device and assembling work into the device are easy. Can be Further, by making the opposite ends of the both inner cases abut against each other, the mounting positions of both rotary rings are defined at the time of mounting, and it is possible to prevent variations in the biasing force of the springs.

[0008]

【Example】

 FIG. 1 shows an embodiment of a cassette type double mechanical seal that is mounted as a shaft sealing device for a pump. 100A is a mechanical seal on the impeller side, which is the sealed space A side, and 100B is a motor side, which is an anti-seal. A mechanical seal on the space B side, 200A is an impeller side housing, 200B is a motor side housing, and 210 is a shaft which is inserted into the inner circumference of both housings 200A and 200B and rotates the impeller by the driving force of the motor.

The two sets of mechanical seals 100 A and 100 B are, for example, a fixed ring 110 made of SiC, which is a hard sliding material, and a rotary ring 120 that is also made of SiC and abuts the fixed ring 110 in the axial direction. And a bellows 130 as a shaft packing made of an elastomer such as NBR, and a steel material integrally fixed by caulking to the rotary ring 120 with the outer diameter portion 131 of the bellows 130 being properly compressed in the axial direction. It includes a side case 140 and a spring 150 that elastically biases the rotating ring 120 in the axial direction via the inner case 140 and the outer diameter side back surface of the bellows 130. The spring 150 is shared by both the mechanical seals 100A and 100B, that is, the pair of rotating rings 120, 120 arranged in the axial direction are opposite to each other by the spring 150 arranged between the rotating rings 120, 120. It is elastically urged against the pair of fixed rings 110, 110 arranged at both ends in the axial direction which is the urging direction.

Reference numerals 160 and 160 respectively denote a pair of steel outer casings fixed to the housings 200A and 200B via O-rings 190 made of an elastomer such as NBR. Outer diameter flanges formed at opposite ends thereof. The parts 161 are integrally coupled to each other via a screw member 170 serving as a linking means, and an inner diameter flange part 162 having an L-shaped cross section and formed in a stepped shape at the opposite end part thereof is connected to the both mechanical seals. The fixed rings 110 of the cables 100A and 100B are fitted via the O-rings 180, respectively. On the outer peripheral wall surface of each outer case 160, a through hole 163 is formed to allow the fluid (lubricating oil) on the outer peripheral side of the mechanical seals 100A and 100B to flow. Further, the fixed ring 110 of the mechanical seal 100A is firmly fixed to the inner diameter flange portion 162 by the washer 164 from the front side thereof, and is prevented from receiving the pressure on the sealed space A side from the rear side and moving.

The fixed ring 110 has a notch 111 formed on the inner surface of the rear surface thereof and an inward projection 165 formed on the inner diameter flange 162, which is loosely engaged with the outer case 160. The outer case 160 itself and the outward protrusion 166 formed on the inner diameter flange portion 162 are loosely fitted by engaging with the notches 201 formed on the inner diameter portions of the housings 200A and 200B. It has been stopped. On the other hand, a notch 121 is also formed in the inner diameter portion of the back surface of the rotary ring 120, and the notch 121 and the protrusion 132 formed on the bellows 130 are loosely engaged with each other, so that the rotary ring 120 and the bellows 130 are joined together. Relative rotation is prevented.

The inner case 140 encloses the entire outer peripheral surface of the bellows 130 to provide a proper tightening allowance for the shaft 210 at the inner diameter portion 133 thereof. The parts 141 and 141 are in contact with each other.

In the cassette type double mechanical seal configured as described above, all the components of the two sets of mechanical seals 100A, 100B are arranged on the inner circumference of the outer cases 160, 160, and the inner diameter flange portion 162, It is held between 162 and is integrated in advance when it is not attached to the pump.

When assembling the double mechanical seal into the pump, first, the O-ring 190 is mounted on the motor-side housing 200B, and then the inner diameter flange portion 162 of the outer case 160 on the mechanical seal 100A side is axially pressed. Then, the inner side flange portion 162 of the outer case 160 on the mechanical seal 100B side is press-fitted along the outer periphery of the shaft 210 until it is pressed against the motor-side housing 200B. At this time, alignment is performed so that the outward protrusion 166 of the outer case 160 on the mechanical seal 100B side enters the notch 201 of the motor-side housing 200B. As a result, the inner diameter flange portion 162 of the outer case 160 on the mechanical seal 100B side is airtightly fitted to the motor side housing 200B via the O-ring 190.

At the time of the press-fitting, the inner diameter portion 133 of the bellows 130 receives frictional resistance by sliding in pressure contact with the outer peripheral surface of the shaft 210, but the inner case 140 holding each bellows 130, Since the rear end portions 141 and 141 of the spring 140 are in contact with each other, the position of the bellows 130, 130 does not shift axially relative to the outer cases 160, 160 due to the frictional resistance, and the spring 150 does not move. The compressed length of is not affected. Further, if lubricating oil is applied to the outer peripheral surface of the shaft 210 in advance, the friction resistance of the inner diameter portion 133 of the bellows 130 made of an elastomer can be reduced and the shaft can be easily press-fitted. At this time, the lubricating oil remaining between the inner diameter portion 133 of the bellows 130 and the shaft 210 is discharged with time by the tightening force of the inner diameter portion 133 of the bellows 130 after the press-fitting is completed. Crimp on.

After the press-fitting is completed, the O-ring 190 is mounted on the impeller-side housing 200A, and then the housing 200A can be assembled to the motor-side housing 200B. At this time, alignment is performed so that the outward protrusion 166 of the outer case 160 on the mechanical seal 100A side enters the notch 201 of the impeller-side housing 200A. As a result, the inner diameter flange portion 162 of the outer case 160 on the mechanical seal 100A side is airtightly fitted to the impeller side housing 200A via the O-ring 190, so that the double mechanical seal can be mounted on the pump. Complete. When fixing the impeller-side housing 200A, the dimensions are set so that a slight gap δ is formed between the housing 200A and the facing end surface of the inner diameter flange portion 162 of the outer case 160 on the mechanical seal 100A side. If this is done, the accuracy in mounting can be buffered.

In the mounting work, unlike the case where the components of the mechanical seals 100A and 100B are individually assembled in sequence, a jig for press fitting may touch the fixed ring 110 and the rotary ring 120. Since the sealing sliding surface S is not damaged by both 110 and 120, the mounting can be performed in a short time. In addition, both mechanical seals 100A and 100B can be collectively removed from the pump by the procedure reverse to the above, and if the outer case 160, 160 is separated by unfastening the screw member 170, the fixed ring 110 and Since the rotary ring 120 is easily disassembled, maintenance is also easy.

Further, in this embodiment, since the fixed ring 110 and the rotary ring 120 are formed of the same material and have the same shape, the fixed ring and the rotary ring have different materials and shapes as in the conventional structure of FIG. By comparison, the manufacturing unit price can be reduced.

[0018]

[Effect of the device]

 As described above, according to the cassette type double mechanical seal according to the present invention, all the constituent parts of the two sets of mechanical seals can be integrated in advance by connecting the both outer cases with the link means, so that Not only can management and mounting work on equipment be facilitated in the unmounted state, but it is also possible to prevent accidental damage to the sealing sliding surface during mounting work, and the opposite ends of both inner cases. With the configuration in which the two abut against each other, the mounting positions of both rotary rings are specified at the time of mounting, so it is possible to prevent variations in the biasing force of the spring and obtain stable sealing performance. Produce the effect.

[Brief description of drawings]

FIG. 1 is a half sectional view showing an embodiment of a cassette type double mechanical seal according to the present invention in relation to a pump which is a mounted side.

FIG. 2 is a half cross-sectional view showing an example of a conventional double mechanical seal in relation to the pump on the mounted side.

[Explanation of symbols]

 100A, 100B Mechanical seal 110 Fixed ring 120 Rotating ring 130 Bellows 140 Inner case 141 Rear end (opposing end) 150 Spring 160 Outer case 161 Outer diameter flange (opposing end) 170 Screw member (linking means) 200A Impeller side Housing 200B Motor side housing 210 Shaft A Sealed space B Anti-sealed space

Claims (2)

[Scope of utility model registration request] 1. A pair of rotating rings arranged in the axial direction are elastically biased in opposite directions by springs arranged between the rotating rings, and a pair of rotating rings are arranged in the biasing direction of each rotating ring. In a double mechanical seal having two sets of mechanical seals that abut against a fixed ring, the both fixed rings are airtightly fitted to the inner circumferences of the pair of outer cases, and the opposite ends of the both outer cases are opposed to each other. A cassette type double mechanical seal characterized by being connected by link means. 2. The cassette type according to claim 1, wherein both rotary rings are biased by springs through the inner cases, and opposite ends of the both inner cases abut against each other. Double mechanical seal.