JP2013113098A - Pump and method for assembling pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump capable of reducing labor hours in manufacturing by facilitating the attachment and detachment of a connecting pipe.SOLUTION: A balance pipe 31 has a suction-side member 39 provided in a casing 7 and communicating with a suction port side; a discharge-side member 40 provided in a casing 8 and communicating with a discharge port side; and a connecting pipe 41 connected between the suction-side member 39 and the discharge-side member 40. The suction-side member 39 and the discharge-side member 40 have insert portions to which the ends of the connecting pipe 41 are inserted respectively. The insert portion of the discharge-side member 40 has a moving space 57 which allows the connecting pipe 41 to be moved in a length direction B after assembling the balance pipe 31.

Description

  The present invention relates to a pump provided with balance piping.

  Conventionally, for example, in a multistage ring-cut pump, as shown in FIG. 21, since the axial thrust F1 from the discharge side to the suction side acts on the main shaft 121, the balance thrust F2 in the opposite direction to the axial thrust F1. And a balance mechanism 122 that balances the axial thrust F1 and the balance thrust F2.

  The balance mechanism 122 includes a balance disk 123 provided on the main shaft 121, a balance sheet 125 provided on the casing 124 and facing the balance disk 123, and a balance pipe 131.

  The casing 124 has a suction casing 139 and a discharge casing 140. In the casing 124, a suction side chamber 127 that communicates with the suction port 126, a balance chamber 129 that is positioned on the bearing box 128 side of the balance mechanism 122, and a discharge side chamber 130 that communicates with the balance chamber 129 are formed. .

  The balance pipe 131 balances the pressure in the suction side chamber 127 and the pressure in the discharge side chamber 130. The balance pipe 131 includes a connection pipe 132 and connection flanges 133 and 134 provided at both ends of the connection pipe 132. Have. One flange 133 is attached to the suction casing 139 by a plurality of bolts 135, and the other flange 134 is attached to the discharge casing 140 by a plurality of bolts 136.

  Note that a sealing material (not shown) such as a gasket is sandwiched between one flange 133 and the suction casing 139 and between the other flange 134 and the discharge casing 140. Accordingly, the balance chamber 129 communicates with the suction port 126 via the discharge side chamber 130, the balance pipe 131, and the suction side chamber 127.

  While the pump 120 is operating, the axial thrust F1 from the discharge side to the suction side acts on the main shaft 121 due to the pressure difference between the front and rear of the rotating impeller 138 (that is, the suction side and the discharge side). The balance thrust F2 in the opposite direction to the axial thrust F1 acts on the balance disk 123, and the axial thrust F1 is counterbalanced by the balance between the axial thrust F1 and the balance thrust F2.

  At this time, a part of the liquid that has passed through the final stage impeller 138 flows through the balance chamber 129, the discharge side chamber 130, the balance pipe 131, and the suction side chamber 127 and merges with the liquid that flows in from the suction port 126. As a result, the pressure in the balance chamber 129 becomes substantially the same as the suction pressure of the pump 120, the balance thrust F2 is generated by the pressure difference generated before and after the balance disk 123, and the balance thrust F2 balanced with the axial thrust F1 is obtained.

  A multistage ring-cut pump including the balance pipe 131 as described above is described in Patent Document 1 below.

JP2000-205165A

  However, in the above conventional type, since the connection pipe 132 is attached to the casing 124 by the flanges 133 and 134 and the bolts 135 and 136, there is a problem that it takes time to install and remove the connection pipe 132.

  Further, when the pump 120 is manufactured, the distance G between the flanges 133 and 134 of the balance pipe 131 needs to be accurately maintained. Therefore, the dimensional accuracy at the time of manufacturing must be increased, and it is troublesome to manufacture the pump 120. There is a problem that requires.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a pump and a pump assembling method in which connection pipes can be easily attached and detached, and the labor for manufacturing can be reduced.

To achieve the above object, the present invention provides a casing having a fluid suction port and a discharge port, a main shaft rotatably supported in the casing, an impeller mounted on the main shaft, and a main shaft. A pump with a thrust balance device equipped with a balance pipe that reduces the axial thrust generated,
The balance pipe is connected between the suction side member provided in the casing and communicating with the suction port side, the discharge side member provided in the casing and communicating with the discharge port side, and the suction side member and the discharge side member. Connecting pipes,
Each of the suction side member and the discharge side member has an insertion part that is inserted with an end of the connection pipe and sealed with a sealing material,
Either one of the suction side member and the discharge side member has a moving space that allows the connection pipe to move in the length direction after the assembly of the balance pipe.

  According to this, by inserting one end of the connection pipe into the insertion part of the discharge side member and inserting the other end of the connection pipe into the insertion part of the suction side member, the connection pipe is connected to the suction side member and the discharge side member. Easily connected between.

  Also, the other end of the connection pipe is removed from the insertion part of the suction side member, and one end of the connection pipe is removed from the insertion part of the discharge side member, so that the connection pipe is connected to the suction side member and the discharge side. It is easily removed from between the members.

  In addition, since either one of the suction side member and the discharge side member has a moving space, there is some variation in the length of the connection pipe and the distance between the suction side member and the discharge side member. Alternatively, the connection pipe can be attached by inserting one end of the connection pipe into the insertion part of the discharge side member and the other end of the connection pipe into the insertion part of the suction side member.

  At this time, the length of the connecting pipe and the variation in the distance between the suction side member and the discharge side member are absorbed in the moving space. There is no need to increase the positional accuracy with respect to the discharge side member, and the labor for manufacturing and assembling the pump can be reduced.

In the pump according to the second aspect of the present invention, when the connecting pipe is moved by the moving space,
The connection pipe is detachable from the other insertion part different from the one insertion part having the moving space.

  According to this, one end of the connection pipe is inserted into the insertion part of the discharge side member and the other end of the connection pipe is inserted into the insertion part of the suction side member. By moving to the back of the moving space of the part, it can be removed from the other insertion part that does not have the moving space. Thereafter, the connecting pipe is moved in the opposite direction, and is removed from the one insertion portion having the moving space. Thereby, connection piping can be easily removed from a discharge side member and a suction side member.

  In addition, when installing the connecting pipe, insert the connecting pipe as far as the moving space of one of the plugs. Thereafter, the connecting pipe is moved in the opposite direction and inserted into the other insertion portion. Thereby, connection piping can be easily attached to a discharge side member and a suction side member.

In the pump according to the third aspect of the present invention, the insertion portion having a moving space is provided on the discharge side member.
According to this, when the balance pipe is attached to the casing and the pump is operating, a part of the fluid flowing in the casing from the suction side to the discharge side flows through the connection pipe from the discharge side member and sucks from the connection pipe. Flow to side member. At this time, since the fluid flow and the frictional force between the connection pipe and the fluid pressure are higher on the discharge side than on the suction side, a one-way force from the discharge side to the suction side acts on the connection pipe.

  Therefore, the connecting pipe does not inadvertently move from the suction side to the discharge side against the unidirectional force, and one end of the connection pipe does not reach the depth of the movement space of the discharge side member. Accordingly, it is possible to prevent the connection pipe from being inadvertently moved to the discharge side to the depth of the moving space during operation and coming off from the suction side member.

The pump according to the fourth aspect of the present invention is provided with a movement restricting member that restricts movement of the connecting pipe in the length direction after the assembly of the balance pipe.
According to this, since the movement of the connecting pipe in the length direction is restricted by the movement restricting member, it is possible to prevent the connecting pipe from falling off from the suction side and the discharge side member.

Moreover, as for the pump in this 5th invention, an insertion part is an insertion hole,
The end of the connection pipe is inserted into the sealing material,
The sealing material is inserted between the outer peripheral surface of the end portion of the connection pipe and the inner peripheral surface of the insertion hole, and is formed in an annular shape having a thin wedge-shaped cross section at the distal end portion in the insertion direction. Being pressed,
Formed on the inner periphery of the sealing material are a straight surface that is located on the distal end side in the insertion direction and has a constant inner diameter, and a tapered surface that gradually increases in diameter from the straight surface toward the base end on the side opposite to the insertion direction. It is what has been.

According to this, since the sealing material has a wedge-shaped cross section, the sealing material can be firmly inserted between the outer peripheral surface of the end portion of the connection pipe and the inner peripheral surface of the insertion hole, and the sealing performance is improved.
Further, the outer peripheral surface of the sealing material is in pressure contact with the inner peripheral surface of the insertion hole, and the inner peripheral surface of the sealing material is in pressure contact with the outer peripheral surface of the end portion of the connection pipe. Under the present circumstances, since the surface pressure of the straight surface of the sealing material with respect to the outer peripheral surface of the end of the connection pipe is higher than the surface pressure of the tapered surface, the sealing performance is further improved. Further, since the straight surface is more strongly pressed against the outer peripheral surface of the end portion of the connecting pipe than the tapered surface, the connecting pipe is fixed, and the connecting pipe can be prevented from inadvertently moving in the length direction.

Further, in the pump according to the sixth invention, the discharge side member is detachably inserted into the discharge side insertion portion formed in the casing,
A support member that supports the balance pipe is provided in the casing.

  According to this, it can prevent that balance piping remove | deviates from a casing by providing a supporting member. The discharge-side member is inserted into the discharge-side insertion portion of the casing, and the attachment of the discharge-side member to the casing is thus made an insertion type, so that the balance pipe can be easily attached to the casing.

Further, in the pump according to the seventh invention, the suction side member is detachably inserted into the suction side insertion portion formed in the casing,
The insertion / removal direction of the suction side member with respect to the suction side insertion portion and the insertion / removal direction of the discharge side member with respect to the discharge side insertion portion are the same direction,
The support member supports the balance pipe so as to limit movement in the insertion / removal direction,
The depth of the suction side insertion part is deeper than the insertion dimension of the suction side member to the suction side insertion part,
The depth of the discharge side insertion portion is formed deeper than the insertion dimension of the discharge side member into the discharge side insertion portion.

  According to this, an extra insertion space is formed between the insertion side tip of the suction side member and the back end of the suction side insertion portion, and similarly, the insertion side tip of the discharge side member and the discharge side insertion portion An extra insertion space is also formed between the rear end portion of the two.

  Due to the dimensional error of the support member or the suction side member or the discharge side member, the connecting pipe is displaced in the insertion / removal direction, and the insertion size of the suction side member or the insertion side of the discharge side member is larger than the normal insertion size. However, since this increase is absorbed by the insertion space, the balance pipe can be easily attached to the casing of the pump.

Moreover, this 8th invention is the assembly method of the pump of any one of the said 1st invention to the 7th invention,
Install the impeller on the main shaft,
An impeller integrated with the main shaft is rotatably mounted in the casing,
Attach the discharge side member to the casing,
Move the connection pipe to the discharge side and insert one end of the connection pipe into the insertion part of the discharge side member.
Move the connection pipe to the suction side, insert the other end of the connection pipe into the insertion part of the suction side member provided in the casing,
The gap between the one end of the connection pipe and the insertion part of the discharge side member and the gap between the other end of the connection pipe and the insertion part of the suction side member are each sealed with a sealing material.

  According to this, balance piping can be easily attached to a casing.

  As described above, according to the present invention, it is easy to attach and detach the connection pipe, and it is possible to reduce the labor of manufacturing the pump.

It is sectional drawing of the multistage pump in the 1st Embodiment of this invention. It is sectional drawing of balance piping provided in the multistage pump. FIG. 3 is an XX arrow view in FIG. 2. It is sectional drawing of the insertion part to the casing of the suction side and discharge side member of balance piping equally. It is sectional drawing of the both ends of the connection piping of balance piping equally. It is sectional drawing of the discharge side elbow of a balance piping. It is a sectional view of the suction side elbow of the balance pipe. It is sectional drawing of the sealing material of balance piping equally. It is a figure which shows the assembly method of balance piping equally. It is a figure which shows the assembly method of balance piping equally. It is a figure which shows the assembly method of balance piping equally. It is a figure which shows the assembly method of balance piping equally. It is a figure which shows the assembly method of balance piping equally. It is a figure which shows the assembly method of balance piping equally. It is sectional drawing of the both ends of the connection piping of the balance piping of the multistage pump in the 2nd Embodiment of this invention. It is sectional drawing of the discharge side elbow of the balance piping of the multistage pump in the 3rd Embodiment of this invention. It is a side view of the balance piping of the multistage pump in the 4th Embodiment of this invention. It is sectional drawing of the both ends of the connection piping of the balance piping of the multistage pump in the 5th Embodiment of this invention. It is sectional drawing of the insertion part to the casing of the discharge side member of the balance piping of the multistage pump in the 6th Embodiment of this invention. It is sectional drawing of the multistage pump in the 7th Embodiment of this invention. It is sectional drawing of the conventional multistage pump.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
First, a first embodiment will be described with reference to FIGS. As shown in FIG. 1, reference numeral 1 denotes a single-body ring-cut multi-stage pump, which has a casing 2 having a suction port 3 and a discharge port 4 for water 21 (an example of fluid), and is rotatable in the casing 2. A main shaft 5 to be supported, a plurality of impellers 6a to 6c mounted on the main shaft 5, and a balance thrust F2 in the opposite direction to the axial thrust F1 from the discharge side to the suction side acting on the main shaft 5 are generated. And a thrust balance device 30 for reducing the axial thrust F1.

  The casing 2 includes a suction casing 7 having a suction port 3, a discharge casing 8 having a discharge port 4, and a plurality of ring-cut intermediate casings 9 a and 9 b sandwiched between the suction casing 7 and the discharge casing 8. It is divided into and. The suction port 3 is formed at the distal end portion of the suction side nozzle portion 52 provided in the suction casing 7, and the discharge port 4 is formed at the distal end portion of the discharge side nozzle portion 53 provided in the discharge casing 8.

  The casings 7, 8, 9 a, 9 b are fastened by fastening means 11 in the axial direction of the main shaft 5. The fastening means 11 has a plurality of fastening bolts 12 inserted through the suction casing 7 and the discharge casing 8 located at both ends, and nuts 18 screwed into both ends of the fastening bolt 12.

  The main shaft 5 is inserted into the casing 2, is received by the bearing device 13, and is sealed with mechanical seals 16 and 17 at the shaft sealing portions on the suction side and the discharge side. Each impeller 6a-6c has the outflow port 19 and the inflow port 20, and the outflow port 19 is located in the radial direction outer side of the main shaft 5 rather than the inflow port 20. As shown in FIG.

  A suction passage 22 is formed in the suction casing 7 to guide the water 21 from the suction port 3 to the inlet 20 of the first stage impeller 6a. The suction passage 22 is formed in an annular shape so as to surround the outer periphery of the main shaft 5, and communicates with the mechanical seal 16 on the suction side through a narrow passage 26.

  In each intermediate casing 9a, 9b, there is formed an intermediate flow path 23 for guiding water 21 from the outlet 19 of each impeller 6a-6c to the inlet 20 of each subsequent impeller 6b, 6c. The intermediate flow path 23 has a diffuser 24 that is formed on the outer side of the outlet 19 of each impeller 6a to 6c and has a plurality of blades in the circumferential direction.

  A discharge passage 25 and a balance chamber 28 are formed in the discharge casing 8. The discharge flow path 25 is a flow path that guides the water 21 that has passed through the final-stage diffuser 24 to the discharge port 4, and is formed in a direction that swirls around the axis of the main shaft 5. The balance chamber 28 is formed in an annular shape so as to surround the outer periphery of the main shaft 5.

  The thrust balance device 30 includes a balance disk 33, a balance sheet 34, and a balance pipe 31 that balances the pressure in the suction flow path 22 and the pressure in the balance chamber 28. The balance disk 33 is a disk-shaped member that is provided on the main shaft 5 and is rotatable together with the main shaft 5, and is housed in the balance chamber 28.

  The balance sheet 34 is an annular member that is provided and fixed in the discharge casing 8, and faces the balance disk 33 from the direction side of the axial thrust F1. The balance disk 33 has a sliding surface that can slide on the balance sheet 34.

  When the surface of the balance disk 33 facing the axial thrust F1 is the front surface and the surface of the balance thrust F2 is the back surface, a narrow first space 35 is formed in the balance chamber 28 on the front surface side of the balance disk 33. A second space 36 is formed on the back side of the balance disk 33. The first space 35 communicates with the outlet 19 of the final stage impeller 6 c through the communication path 37. The second space 36 communicates with the discharge-side mechanical seal 17 through a narrow passage 38.

  As shown in FIGS. 1 to 3, the balance pipe 31 is attached to the suction casing 7 and communicates with the suction flow path 22 (an example of the suction port side) and the discharge casing 8 to be balanced. It has a discharge side member 40 communicating with the chamber 28 (an example of the discharge port side), and a connection pipe 41 connected between the suction side member 39 and the discharge side member 40.

  The suction side member 39 has a suction side pipe 42 and a suction side elbow 43 (an example of a suction side joint), and the discharge side member 40 has a discharge side pipe 48 and a discharge side elbow 49 (an example of a discharge side joint). doing. One end of the connection pipe 41 communicates with the discharge side pipe 48 via the discharge side elbow 49, and the other end of the connection pipe 41 communicates with the suction side pipe 42 via the suction side elbow 43.

  The tip of the suction side pipe 42 is screwed into and connected to the suction side elbow 43. The suction casing 7 is formed with a suction-side insertion hole 44 (an example of a suction-side insertion portion), and a proximal end portion of the suction-side tube 42 is removably inserted into the suction-side insertion hole 44. As shown in FIG. 4, the depth D of the suction side insertion hole 44 is formed deeper than the normal insertion dimension E of the suction side tube 42 into the suction side insertion hole 44, and thus, An extra insertion space 88 is formed between the insertion-side tip and the back end of the suction-side insertion hole 44. The inner end of the suction side insertion hole 44 communicates with the suction flow path 22 through a suction side communication hole 45 having a smaller diameter than the suction side insertion hole 44.

  A groove 46 is formed on the outer peripheral surface of the proximal end portion of the suction side tube 42, and an O-ring 47 is fitted into the groove 46. The suction surface of the suction side tube 42 and the inner peripheral surface of the suction side insertion hole 44 are formed. The gap is sealed with an O-ring 47.

  The distal end portion of the discharge side pipe 48 is screwed into and connected to the discharge side elbow 49. In addition, a discharge side insertion hole 50 (an example of a discharge side insertion portion) is formed in the discharge casing 8, and a base end portion of the discharge side tube 48 is inserted into the discharge side insertion hole 50 in a detachable manner. The depth D of the discharge side insertion hole 50 is formed to be deeper than the normal insertion dimension E of the discharge side tube 48 into the discharge side insertion hole 50, whereby the insertion side tip of the discharge side tube 48 and the discharge side are formed. An extra insertion space 89 is formed between the inner end of the insertion hole 50. Note that the inner end of the discharge side insertion hole 50 communicates with the balance chamber 28 through a discharge side communication hole 51 having a smaller diameter than the discharge side insertion hole 50.

  A groove 46 is formed on the outer peripheral surface of the proximal end portion of the discharge side tube 48, and an O-ring 47 is fitted into the groove 46, and the outer peripheral surface of the discharge side tube 48 and the inner peripheral surface of the discharge side insertion hole 50 are formed. The gap is sealed with an O-ring 47.

2 and 4, the insertion / removal direction A of the suction side tube 42 with respect to the suction side insertion hole 44 and the insertion / removal direction A of the discharge side tube 48 with respect to the discharge side insertion hole 50 are the same direction.
As shown in FIGS. 5 and 6, the discharge-side elbow 49 has a first screw hole 55 into which the discharge-side pipe 48 is screwed and a first difference into which one end portion (discharge-side end portion) of the connection pipe 41 is inserted. It has the insertion hole 56 (an example of one insertion part). The first screw hole 55 and the first insertion hole 56 communicate with each other from the orthogonal direction inside the discharge-side elbow 49.

  The first insertion hole 56 has a movement space 57 that allows the connection pipe 41 to move in the length direction B after the balance pipe 31 is assembled. The diameter of the first insertion hole 56 is set slightly larger than the outer diameter of one end portion of the connection pipe 41.

  As shown in FIGS. 5 and 7, the suction-side elbow 43 includes a second screw hole 60 into which the suction-side pipe 42 is screwed and a second screw hole 60 into which the other end (suction-side end) of the connection pipe 41 is inserted. It has the insertion hole 61 (an example of the other insertion part different from the one insertion part which has a movement space), and the communicating hole 62. As shown in FIG. The second screw hole 60 and the second insertion hole 61 are orthogonal to and communicated with each other through the communication hole 62 inside the suction side elbow 43.

  The diameter of the second insertion hole 61 is set slightly larger than the outer diameter of the other end of the connection pipe 41, and the diameter of the communication hole 62 is set smaller than the outer diameter of the other end of the connection pipe 41. In addition, a stepped portion 63 (an example of a movement restricting member) that protrudes radially inward is formed at the boundary portion between the second insertion hole 61 and the communication hole 62 over the entire circumference.

  As shown in FIGS. 2 and 5, the connection pipe 41 is a straight pipe, one end of which is inserted into the first insertion hole 56 of the discharge side elbow 49, and the other end is the second of the suction side elbow 43. It is possible to move in the length direction B while being inserted into the insertion hole 61. When the connection pipe 41 is moved by the moving space 57 in the direction B1 from the suction side to the discharge side in the length direction B, the other end of the connection pipe 41 is detached from the second insertion hole 61 of the suction side elbow 43. It is possible to remove. Further, the movement of the connection pipe 41 in the direction B2 opposite to the direction B1 is limited by the stepped portion 63.

  The dimensional relationship will be described here. The distance L1 of the moving space 57 of the first insertion hole 56 of the discharge-side elbow 49 (that is, the connection pipe 41 is connected in a state where the other end of the connection pipe 41 is in contact with the stepped portion 63. The depth L2 of the second insertion hole 61 of the suction side elbow 43 (that is, the distance from one end of the pipe 41 to the back end of the moving space 57) (that is, the second insertion hole from the end face of the suction side elbow 43). The length of the connection pipe 41 is set so as to be larger than the distance to the rear end of 61.

  A gap between one end of the connection pipe 41 and the first insertion hole 56 is sealed with a first sealing material 66, and a gap between the other end of the connection pipe 41 and the second insertion hole 61 is a second. Sealed with a sealing material 67.

  Both ends of the connection pipe 41 are inserted into the first and second sealing materials 66 and 67, respectively. The first seal material 66 is connected to the outer peripheral surface of one end of the connection pipe 41 and the inner periphery of the first insertion hole 56. It is inserted into a seal insertion part 68 formed between the surface and pressed in the insertion direction C by a pressing member 69.

  The second seal material 67 is inserted into a seal insertion portion 68 formed between the outer peripheral surface of the other end portion of the connection pipe 41 and the inner peripheral surface of the second insertion hole 61, and a pressing member 69. Is pressed in the insertion direction C.

  As shown in FIG. 8, each of the first and second sealing members 66 and 67 is formed in an annular shape having a wedge-shaped cross section that is thinner toward the tip in the insertion direction C. On the inner circumferences of the first and second sealing materials 66 and 67, a straight surface 71 located at the tip in the insertion direction C and having a constant inner diameter, and the straight surface 71 opposite to the insertion direction C, respectively. A tapered surface 72 that gradually increases in diameter toward the proximal end portion is formed. As shown in FIGS. 6 and 7, each seal insertion portion 68 has a truncated cone shape, that is, the same shape as the first and second sealing materials 66 and 67, and the first and second It is formed in the opening side edge part of the insertion holes 56 and 61.

  As shown in FIG. 5, each push member 69 is a disk-like member having a through hole 74 through which the connection pipe 41 is inserted at the center, and a plurality of bolts 75 are used to suck and discharge side elbows 43, 49.

  In the discharge-side elbow 49, both ends of the connection pipe 41 are inserted into the first and second insertion holes 56 and 61, respectively, and the balance pipe 31 is assembled. Then, the connection pipe 41 is moved in the length direction B. A movement restriction pin 77 (an example of a movement restriction member) for restriction is provided. The movement limiting pin 77 is detachably screwed into a screw hole 78 formed in the discharge-side elbow 49, and a tip end portion projects into the movement space 57 of the first insertion hole 56 from the radial direction. The gap between the movement limiting pin 77 and the discharge side elbow 49 is sealed with a sealing material such as a sealing tape.

  As shown in FIGS. 1 and 2, the discharge casing 8 is provided with a support member 79 that supports the balance pipe 31 so as to limit movement in the insertion / removal direction A. A base end portion of the support member 79 is detachably connected to the discharge casing 8 by a plurality of bolts 81. Further, the connection pipe 41 is detachably connected to the distal end portion of the support member 79 by a U bolt 82 and a nut 83.

  A first flushing pipe 85 is connected between the discharge-side mechanical seal 17 and the discharge-side elbow 49, and a second flushing pipe 85 is connected between the suction-side mechanical seal 16 and the suction-side elbow 43. A tube 86 is connected.

Hereinafter, the operation of the above configuration will be described.
First, the assembly method of the multistage pump 1 is demonstrated based on the following procedures (1)-(12).
(1) The impellers 6 a to 6 c are attached to the main shaft 5, and the impellers 6 a to 6 c integrated with the main shaft 5 are rotatably installed in the casing 2. At this time, the bearing device 13, the mechanical seals 16 and 17, the balance disk 33, the balance sheet 34 and the like are also attached, and the pump body is assembled.

Thereafter, as shown in FIG. 9, the support member 79 is attached to the discharge casing 8 using the bolt 81.
(2) Next, as shown in FIG. 10, the distal end portion of the discharge side tube 48 is screwed into the first screw hole 55 of the discharge side elbow 49 to assemble the discharge side member 40, and the distal end portion of the suction side tube 42 is The suction side member 39 is assembled by screwing into the second screw hole 60 of the suction side elbow 43.

(3) As shown in FIG. 11, using the U bolt 82 and the nut 83, the connection pipe 41 is loosely temporarily assembled to the support member 79 while being maintained in a state of being movable in the length direction B.
(4) One end of the connection pipe 41 is inserted into the first sealing material 66 and the through hole 74 of the pressing member 69, and the other end of the connection pipe 41 is inserted into the second sealing material 67 and the through hole 74 of the pressing member 69. And the first and second sealing members 66 and 67 and the pressing member 69 are externally fitted to the connection pipe 41.

(5) As shown in FIG. 12, the base end portion of the discharge side pipe 48 of the discharge side member 40 is inserted into the discharge side insertion hole 50, and the discharge side member 40 is attached to the discharge casing 8.
(6) The connection pipe 41 temporarily assembled to the support member 79 in the procedure (3) is moved from the suction side to the discharge side direction B1, and one end of the connection pipe 41 is moved to the first difference of the discharge elbow 49. Insert into the insertion hole 56. At this time, as shown in FIG. 12, one end of the connection pipe 41 is inserted until it reaches the innermost part of the moving space 57 of the discharge side elbow 49.

(7) As shown in FIG. 13, the proximal end portion of the suction side pipe 42 of the suction side member 39 is inserted into the suction side insertion hole 44, and the suction side member 39 is attached to the suction casing 7.
(8) As shown in FIG. 14, the connection pipe 41 is moved in the direction B2 opposite to the direction B1 (that is, the direction from the discharge side to the suction side), and the other end of the connection pipe 41 is moved to the suction side elbow. 43 is inserted into the second insertion hole 61. At this time, the connection pipe 41 is inserted until the other end abuts against the stepped portion 63 of the suction side elbow 43.

(9) As shown in FIG. 2, the U-bolt 82 and the nut 83 are tightened to fix the connection pipe 41 to the support member 79.
(10) As shown in FIG. 5, the first seal member 66 is inserted into the seal insertion portion 68 of the discharge-side elbow 49, the bolt 75 is tightened, and the first seal member 66 is inserted in the insertion direction C by the push member 69. The second sealing material 67 is inserted into the seal insertion portion 68 of the suction side elbow 43, the bolt 75 is tightened, and the second sealing material 67 is pressed in the insertion direction C by the pressing member 69. Thereby, between the one end part of the connection piping 41 and the 1st insertion hole 56 of the discharge side elbow 49 and between the other end part of the connection piping 41, and the 2nd insertion hole 61 of the suction side elbow 43. Sealed with first and second sealing materials 66 and 67, respectively.

(11) The movement limiting pin 77 is screwed into the screw hole 78 of the discharge side elbow 49 and attached.
(12) As shown in FIG. 1, the first flushing pipe 85 is connected between the discharge-side mechanical seal 17 and the discharge-side elbow 49, and the second flushing pipe 86 is connected to the suction-side mechanical seal 16. And the suction side elbow 43.

  According to the assembly method as shown in the above (1) to (12), as shown in FIG. 5, the first insertion hole 56 of the discharge-side elbow 49 has an extra moving space 57. Even if there is some variation in the length of the connection pipe 41 and the interval between the suction side member 39 and the discharge side member 40, as shown in the procedures (6) and (8), one end of the connection pipe 41 is connected to the first end. By inserting the other end of the connection pipe 41 into the second insertion hole 61, the connection pipe 41 can be easily connected between the elbows 43 and 49.

  At this time, the variation in the length of the connection pipe 41 and the variation in the interval between the suction side member 39 and the discharge side member 40 are absorbed by the moving space 57. It is not necessary to increase the dimensional accuracy and the positional accuracy of the suction side member 39 and the discharge side member 40, and the labor for manufacturing and assembling the balance pipe 31 can be reduced.

  Further, as shown in the above procedure (11), by attaching the movement restricting pin 77 to the discharge side elbow 49, the tip of the movement restricting pin 77 protrudes into the moving space 57 of the first insertion hole 56. . When one end of the connection pipe 41 abuts against the tip of the movement restriction pin 77, the connection pipe 41 is restricted from inadvertently moving from the suction side to the discharge side direction B1. Further, the other end of the connection pipe 41 abuts on the stepped portion 63, so that the connection pipe 41 is prevented from inadvertently moving in the direction B2 opposite to the direction B1. Accordingly, the connection pipe 41 is prevented from inadvertently moving in the length direction B (that is, the direction B1, B2), and the other end of the connection pipe 41 is inadvertently inserted into the second elbow 43 of the suction side elbow 43. It is possible to prevent the connection pipe 41 from being removed from between the elbows 43 and 49 by being removed from the hole 61.

  Further, as shown in FIG. 2, by attaching the support member 79 to the casing 2 and supporting the balance pipe 31 with the support member 79, it is possible to prevent the balance pipe 31 from coming off the casing 2.

  Further, the suction side tube 42 of the suction side member 39 is inserted into the suction side insertion hole 44, and the discharge side tube 48 of the discharge side member 40 is inserted into the discharge side insertion hole 50. The attachment of the balance pipe 31 to the casing 2 is facilitated by making the attachment method of the suction side and discharge side members 39, 40 into the insertion type.

  Further, an extra insertion space 88 is formed between the insertion side distal end portion of the suction side tube 42 and the rear end portion of the suction side insertion hole 44. Similarly, the insertion side distal end portion of the discharge side tube 48 An extra insertion space 89 is formed between the inner end of the discharge side insertion hole 50.

  Here, due to a dimensional error of the height H of the support member 79, the connection pipe 41 is supported while being displaced in the insertion / removal direction A, and the insertion dimension of the suction side pipe 42 or the insertion dimension of the discharge side pipe 48 is the normal insertion dimension. Even if it increases from E, this increase is absorbed by the insertion spaces 88 and 89.

Thereby, even if the connection pipe 41 is in a state of being supported while being displaced in the insertion / removal direction A, the balance pipe 31 can be easily attached to the casing 2 of the multistage pump 1.
Further, as shown in FIG. 8, since the first and second sealing members 66 and 67 have wedge-shaped cross sections, respectively, as shown in FIG. By pressing in the insertion direction C by the member 69, the first and second sealing members 66 and 67 are connected to the respective seal insertion portions 68 (that is, the outer peripheral surface of the end portion of the connection pipe 41 and the first and second insertion holes 56. , 61 between the connection pipe 41 and the suction-side elbow 43 or between the connection pipe 41 and the discharge-side elbow 49 is improved.

  At this time, the outer peripheral surfaces of the first and second seal members 66 and 67 are in pressure contact with the inner peripheral surfaces of the seal insertion portions 68 (that is, the inner peripheral surfaces of the insertion holes 56 and 61), and the first and second The inner peripheral surfaces of the sealing materials 66 and 67 are in pressure contact with the outer peripheral surface of the end portion of the connection pipe 41. At this time, the surface pressure of the straight surfaces 71 (see FIG. 8) of the first and second sealing members 66 and 67 against the outer peripheral surface of the end portion of the connection pipe 41 is higher than the surface pressure of the tapered surface 72 (see FIG. 8). Therefore, the sealing performance is further improved.

  The reason why the surface pressure of the straight surface 71 is higher than the surface pressure of the tapered surface 72 as described above is that when the sealing materials 66 and 67 are pushed in by the pushing member 69, the sealing materials 66 and 67 near the straight surface 71. This is because the filling degree is higher than the filling degree of the sealing materials 66 and 67 near the tapered surface 72.

  That is, when the sealing members 66 and 67 are pushed in by the pushing member 69, first, the vicinity of the straight surface 71 is first subjected to the wedge resistance (the sealing materials 66 and 67 are first filled), and then the vicinity of the tapered surface 72. Since the sealing materials 66 and 67 are filled with the wedge resistance, the filling degree of the sealing materials 66 and 67 near the straight surface 71 becomes higher than the filling degree of the sealing materials 66 and 67 near the tapered surface 72.

  Moreover, the structure which formed the straight surface 71 and the taper surface 72 in the inner periphery of the sealing materials 66 and 67 is the movement to the pipe length direction of the sealing materials 66 and 67 which were let the connection piping 41 pass at the time of the assembly of the balance piping 31. It is also the structure which makes it easy and improves workability | operativity.

  That is, considering the sealing properties of the sealing materials 66 and 67, the inner diameters of the sealing materials 66 and 67 and the outer diameter of the connecting pipe 41 are slightly fitted, so that the entire inner surfaces of the sealing materials 66 and 67 are straight surfaces. This is because the contact surface between the sealing materials 66 and 67 and the connection pipe 41 is smaller than that of 71, the frictional force is reduced, and the movement of the sealing materials 66 and 67 on the connection pipe 41 is facilitated.

  In addition, since the straight surface 71 is stronger than the tapered surface 72 and presses against the outer peripheral surface of the end portion of the connection pipe 41, the connection pipe 41 can be more reliably prevented from inadvertently moving in the length direction B. .

  After the balance pipe 31 is attached by the procedures (1) to (12) as described above, the multistage pump 1 is operated, so that the impellers 6a to 6c and the balance disk 33 together with the main shaft 5 are operated as shown in FIG. The water 21 is sucked from the suction port 3, flows through the suction flow path 22 from the inlet 20 of each impeller 6 a to 6 c to the outlet 19, and flows through the final stage diffuser 24. It flows through the passage 25 and is guided to the discharge port 4. At this time, axial thrust F <b> 1 is generated on the main shaft 5.

  When the multistage pump 1 is operating as described above, a part of the water 21 flowing out from the outlet 19 of the final stage impeller 6 c passes through the communication path 37 to the first space 35 in the balance chamber 28. 2 and flows into the second space 36 through the gap between the balance disk 33 and the balance sheet 34 from the first space 35, and from the second space 36, as shown in FIG. 2, the discharge side communication hole 51, the discharge side insertion hole 50, The discharge side pipe 48, the discharge side elbow 49, the connection pipe 41, the suction side elbow 43, the suction side pipe 42, the suction side insertion hole 44, and the suction side communication hole 45 flow into the suction flow path 22, and from the suction port 3. It merges with the inflowing water 21.

Here, if the pressure in the first space 35 is P1, the pressure in the second space 36 is P2, and the pressure in the suction flow path 22 (ie, the suction pressure) is P0, the second space 36, the suction flow path 22 and Are communicated via the balance pipe 31, so that each pressure is maintained in the following relationship.
P1> P2≈P0
As a result, as shown in FIG. 1, a balance thrust F2 is generated on the main shaft 5 via the balance disk 33, and the axial thrust F1 and the balance thrust F2 are balanced against each other.

  Further, as shown in FIG. 2, the pressure of the water 21 flowing in the multistage pump 1 has a higher pressure on the discharge side than the suction side, and the frictional force between the flow of the water 21 and the connection pipe 41. A one-way force F3 from the discharge side to the suction side acts. Therefore, the connection pipe 41 does not inadvertently move from the suction side to the discharge side against the unidirectional force F3, and one end of the connection pipe 41 is at the innermost part of the moving space 57 of the discharge side elbow 49. Never reach. That is, since the movement space 57 of the discharge side elbow 49 is in a position opposite to the one-way force F <b> 3, it is possible to prevent the other end portion of the connection pipe 41 from being detached from the suction side elbow 43.

  Further, as shown in FIG. 1, a part of the water 21 flowing into the second space 36 due to the pressure difference between the mechanical seal 17 and the balance pipe 31 passes through the narrow passage 38 from the second space 36 on the discharge side. After being supplied into the mechanical seal 17 and flowing through the mechanical seal 17, it flows into the discharge-side elbow 49 from the mechanical seal 17 via the first flushing pipe 85, or such a flow direction is On the contrary, it flows in the mechanical seal 17 from the discharge side elbow 49 via the first flushing pipe 85. As a result, the discharge-side mechanical seal 17 is flushed (washed).

  Similarly, a part of the water 21 flowing into the suction flow path 22 due to the pressure difference between the mechanical seal 16 and the balance pipe 31 is supplied from the suction flow path 22 through the narrow passage 26 into the suction side mechanical seal 16. Then, after flowing through the mechanical seal 16, it flows into the suction side elbow 43 from the mechanical seal 16 via the second flushing pipe 86, or, contrary to such a flow direction, the suction side elbow 43 flows through the mechanical seal 16 through the second flushing pipe 86. Thereby, the suction side mechanical seal 16 is flushed.

  In the present embodiment, the first and second flushing pipes 85 and 86 are connected to the balance pipe 31, but are connected to a plug seat or the like provided on the casing 2 that provides pressure necessary for flushing. May be.

  Moreover, when removing the balance piping 31 from the multistage pump 1, what is necessary is just to perform the reverse of the assembly procedure (1)-(12) mentioned above. At this time, after the movement restricting pin 77 is removed from the discharge-side elbow 49, each bolt 75 is removed, and the first and second seal members 66 and 67 are removed from each seal insertion portion 68. Next, the U bolt 82 and the nut 83 are removed from the support member 79, and as shown in FIG. 13, the connection pipe 41 is moved from the suction side to the discharge direction B1 for 57 minutes, and one end of the connection pipe 41 is moved. The moving space 57 is brought into contact with the innermost part. Thereby, the other end of the connection pipe 41 can be removed from the second insertion hole 61 of the suction side elbow 43.

  Thereafter, the suction side pipe 42 is removed from the suction side insertion hole 44, the suction side member 39 is removed from the suction casing 7, and the connection pipe 41 is moved in the direction B2 opposite to the direction B1. Can be removed from the first insertion hole 56 of the discharge-side elbow 49, and the connection pipe 41 can be easily detached from both elbows 43 and 49.

  In the said 1st Embodiment, although the suction side member 39 and the discharge side member 40 are provided in the casing 2 as a separate member, you may use a part of casing 2 as a suction side member or a discharge side member, for example, As in a seventh embodiment to be described later, a suction side nozzle portion 52 that is a part of the casing 2 may be used as a suction side member, or a discharge side nozzle portion that is a part of the casing 2. 53 may be used as the discharge side member.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG.
The discharge-side elbow 49 includes a first screw hole 55, a cylindrical first insertion protrusion 93 (an example of one insertion part) that is inserted into one end of the connection pipe 41, and a first communication hole. 94. One end of the first communication hole 94 opens at the distal end surface of the first insertion protrusion 93, and the other end communicates perpendicularly to the first screw hole 55 in the discharge-side elbow 49.

The first insertion protrusion 93 has a movement space 57 that allows the connection pipe 41 to move in the length direction B after the balance pipe 31 is assembled.
The suction-side elbow 43 includes a second screw hole 60, a cylindrical second insertion protrusion 97 (an example of the other insertion portion) that is inserted into the other end of the connection pipe 41, and a second communication. Hole 98. One end of the second communication hole 98 opens at the distal end surface of the second insertion protrusion 97, and the other end communicates perpendicularly to the second screw hole 60 in the suction side elbow 43. Further, a stepped portion 99 (an example of a movement restricting member) protruding outward in the radial direction is formed on the outer peripheral surface of the second insertion protrusion 97 over the entire periphery.

  The first insertion protrusion 93 of the discharge side elbow 49 is inserted into one end of the connection pipe 41, and the second insertion protrusion 97 of the suction side elbow 43 is inserted into the other end of the connection pipe 41. The connection pipe 41 is connected between the elbows 43 and 49 in a state in which the connection pipe 41 is movable in the length direction B.

  When the connection pipe 41 is moved in the direction B1 from the suction side to the discharge side by the movement space 57, the other end of the connection pipe 41 can be removed from the second insertion protrusion 97 of the suction side elbow 43. Further, the movement of the connection pipe 41 in the direction B2 opposite to the direction B1 is limited by the stepped portion 99.

  Here, the dimensional relationship will be described. The distance L1 of the moving space 57 of the discharge-side elbow 49 (that is, the moving space from one end of the connecting pipe 41 in a state where the other end of the connecting pipe 41 is in contact with the stepped portion 99). The length of the connecting pipe 41 is set such that the distance to the back end of 57 is larger than the insertion dimension L3 of the second insertion protrusion 97 of the suction side elbow 43.

  A space between the inner peripheral surface of one end of the connection pipe 41 and the outer peripheral surface of the first insertion protrusion 93 of the discharge-side elbow 49 is sealed with the first sealing material 101, and the inner end of the other end of the connection pipe 41 is inside. A space between the peripheral surface and the outer peripheral surface of the second insertion protrusion 97 of the suction side elbow 43 is sealed with a second sealing material 102. Each of the first and second sealing materials 101 and 102 is an O-ring, and is fitted into a groove 103 formed on the outer peripheral surface of the first and second insertion protrusions 93 and 97.

  The first insertion protrusion 93 of the discharge-side elbow 49 has a movement restriction screw 100 (an example of a movement restriction member) that restricts movement of the connection pipe 41 in the length direction B after the balance pipe 31 is assembled. Is provided. The movement limiting screw 100 is detachably screwed into a screw hole 78 formed in the first insertion protrusion 93. The clearance between the movement limiting screw 100 and the discharge-side elbow 49 is sealed with a sealing material such as an O-ring.

Hereinafter, the operation of the above configuration will be described.
Since the first insertion protrusion 93 of the discharge-side elbow 49 has an extra movement space 57, even if there is some variation in the length of the connection pipe 41, the first end of the connection pipe 41 is connected to the first end. By inserting the other end of the connection pipe 41 into the second insertion protrusion 97, the connection pipe 41 can be easily connected between the elbows 43 and 49. At this time, the variation in the length of the connection pipe 41 as described above is absorbed by the moving space 57.

  Further, by attaching the movement limiting screw 100 to the first insertion protrusion 93 of the discharge-side elbow 49, one end of the connection pipe 41 abuts on the movement limiting screw 100, and the connection pipe 41 is moved from the suction side to the discharge side. Inadvertent movement in the direction B1 is restricted. Further, the other end of the connection pipe 41 abuts on the stepped portion 99, so that the connection pipe 41 is prevented from inadvertently moving in the direction B2 opposite to the direction B1. Thereby, the connection pipe 41 is prevented from inadvertently moving in the length direction B, and the connection pipe 41 can be prevented from falling off between the elbows 43 and 49.

  Further, when removing the connection pipe 41 from between the elbows 43 and 49, the movement limiting screw 100 is removed from the discharge side elbow 49, and the connection pipe 41 is directed from the suction side to the discharge side as shown by the phantom line in FIG. The moving space 57 is moved to B1 for 57 minutes, and one end of the connection pipe 41 is brought into contact with the innermost portion of the moving space 57. Thereby, the other end of the connection pipe 41 can be removed from the second insertion protrusion 97 of the suction side elbow 43.

  Thereafter, the connection pipe 41 is moved in the direction B2 opposite to the direction B1 to remove one end of the connection pipe 41 from the first insertion protrusion 93 of the discharge side elbow 49. Thereby, the connection piping 41 can be easily removed from both elbows 43 and 49.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG.
The movement limiting pin 77 is detachably screwed into a screw hole 78 formed in the discharge-side elbow 49 and protrudes into the movement space 57 from the length direction B of the connection pipe 41.

According to this, the one end of the connection pipe 41 abuts against the tip of the movement restriction pin 77, so that the connection pipe 41 is restricted from inadvertently moving from the suction side to the discharge direction B1.
(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIG.

  A pair of movement restricting convex members 105 a and 105 b (an example of a movement restricting member) facing each other in the length direction B are provided on the outer peripheral surface of the connection pipe 41. In a state where the balance pipe 31 is attached to the casing 2, a U bolt 82 is fitted between the pair of movement restricting convex members 105 a and 105 b.

  According to this, when one movement restricting convex member 105a abuts on the U bolt 82, the connection pipe 41 is restricted from inadvertently moving from the suction side to the discharge side direction B1. Further, when the other movement restricting convex member 105b abuts on the U bolt 82, it is restricted that the connecting pipe 41 is inadvertently moved in the direction B2 opposite to the direction B1. This prevents the connection pipe 41 from inadvertently moving in the length direction B.

  When removing the connection pipe 41 from between the elbows 43 and 49, the movement restriction on the connection pipe 41 is released by removing the U-bolt 82 from the support member 79 and separating it from between the movement restriction convex members 105a and 105b. Then, the connecting pipe 41 may be moved in the length direction B.

  In the fourth embodiment, the movement limiting convex members 105a and 105b are provided in the connection pipe 41 as an example of the movement limiting member. However, instead of the movement limiting convex members 105a and 105b, the movement limiting concave part is connected to the connection pipe. It may be formed on the outer peripheral surface of 41 and the U bolt 82 may be attached to the support member 79 and fitted into the movement restricting recess.

(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIG.
The tips of the suction side and discharge side pipes 42 and 48 are bent into an L shape at right angles. The second screw hole 60 and the second insertion hole 61 of the suction side joint 107 provided at the distal end portion of the suction side pipe 42 are formed on the same axis as the connection pipe 41. Similarly, the first screw hole 55 and the first insertion hole 56 of the discharge side joint 108 provided at the distal end portion of the discharge side pipe 48 are formed on the same axis as the connection pipe 41.

According to this, the same operation and effect as the first embodiment can be obtained.
(Sixth embodiment)
Next, a sixth embodiment will be described with reference to FIG.

  The discharge side member 40 includes a discharge side pipe 48, a discharge side elbow 49 (not shown), and an adapter 110. The discharge side elbow 49 is attached to one end of the discharge side pipe 48. The adapter 110 is a cylindrical member having an outer diameter larger than the outer diameter of the discharge side tube 48, and is connected to the other end of the discharge side tube 48 by screwing the other end of the discharge side tube 48. Has been. Further, the thickness of the adapter 110 in the radial direction is formed to be thicker than the thickness of the discharge side pipe 48.

  The adapter 110 is removably inserted into the discharge side insertion hole 50. A groove 46 is formed on the outer peripheral surface of the adapter 110, and an O-ring 47 is fitted in the groove 46. The gap between the outer peripheral surface of the adapter 110 and the inner peripheral surface of the discharge side insertion hole 50 is sealed by the O-ring 47. Has been.

  According to this, it is possible to form the groove 46 having a sufficient depth in the adapter 110, and it is not necessary to increase the thickness of the discharge side pipe 48 in order to form the groove 46. The thickness can be reduced.

  In the sixth embodiment, the adapter 110 is connected to the discharge side pipe 48 of the discharge side member 40. Similarly, the adapter 110 may be connected to the suction side pipe 42 of the suction side member 39. Good.

(Seventh embodiment)
Next, a seventh embodiment will be described with reference to FIG.
In the first embodiment, as shown in FIGS. 1 and 2, the suction side member 39 is configured by the suction side pipe 42 and the suction side elbow 43. In the seventh embodiment, FIG. As shown, the suction side pipe 42 and the suction side elbow 43 are not provided, and the suction side nozzle portion 52 that is a part of the suction casing 7 is used as the suction side member.

  The suction-side nozzle portion 52 includes a second insertion hole 61 (an example of the other insertion portion) into which the other end portion (suction-side end portion) of the connection pipe 41 is inserted, and a depth of the second insertion hole 61. A communication hole 111 communicating from the end to the inner peripheral surface of the suction side nozzle portion 52 is provided. At the boundary portion between the second insertion hole 61 and the communication hole 111, a stepped portion 63 (an example of a movement limiting member) that protrudes radially inward is formed over the entire circumference. The suction side push member 69 is connected to the outer peripheral surface of the suction side nozzle portion 52 by a bolt 75.

According to this, the same operation and effect as the first embodiment can be obtained.
In this embodiment, the support member 79 is provided in the discharge casing 8, but when the impellers 6a to 6c have a small number of stages and the balance pipe 31 has a short length, the discharge side pipe 48 is connected to the discharge side. Since the possibility of falling out from the insertion hole 50 is reduced, the support member 79 may not be provided.

  In each of the above embodiments, as shown in FIGS. 5, 15, 16, and 18, the tip of the suction side pipe 42 is screwed into and connected to the suction side elbows 43 and 107, and FIG. As shown in FIGS. 16, 18, and 20, the distal end portion of the discharge side pipe 48 is screwed into and connected to the discharge side elbows 49 and 108, but is not limited to such a screw type, For example, the tip of the suction side pipe 42 is inserted and connected to the suction side elbows 43 and 107, and the tip of the discharge side pipe 48 is inserted and connected to the discharge side elbows 49 and 108. There may be a flange type.

  In each of the above embodiments, as shown in FIG. 2, the connection pipe 41 is constituted by a single straight pipe, but a plurality of divided pipes divided in the length direction B are connected by a pipe joint. One straight pipe may be used as the connection pipe 41.

  In each of the above embodiments, as shown in FIG. 1, the single-stage ring-cut type multistage pump 1 has been described as an example of the pump. However, the pump is not limited to this type of pump, but another type of pump. It may be.

  In each of the embodiments described above, the thrust balance device 30 having the balance disk 33, the balance sheet 34, and the balance pipe 31 has been described. However, the thrust balance having the balance mechanism 33 and the balance pipe 31 other than the balance disk 33 and the balance sheet 34 is exemplified. The device 30 may be used.

In each of the above embodiments, the water 21 is given as an example of the fluid flowing through the pump. However, a liquid or gas other than the water 21 may be used.
Further, in each of the above embodiments, as shown in FIGS. 5 and 18, the first insertion hole 56 of the discharge side member 40 has the movement space 57, but the second side of the suction side member 39. The insertion hole 61 may have a moving space 57. Similarly, as shown in FIG. 15, the first insertion protrusion 93 of the discharge side member 40 has a movement space 57, but the second insertion protrusion 97 of the suction side member 39 has a movement space. 57 may be included.

  In the first to sixth embodiments, one support member 79 is attached to the casing 2. However, a plurality of support members 79 are attached, and the balance pipe 31 is supported by the plurality of support members 79. May be.

  Moreover, you may use the balance piping 31 of the structure which combined said each embodiment.

DESCRIPTION OF SYMBOLS 1 Multistage pump 2 Casing 3 Inlet 4 Outlet 5 Main shaft 6a-6c Impeller 21 Water (fluid)
30 Thrust balance device 31 Balance piping 39 Suction side member 40 Discharge side member 41 Connection piping 44 Suction side insertion hole (suction side insertion portion)
50 Discharge side insertion hole (Discharge side insertion part)
52 Suction side nozzle (suction side member)
56 1st insertion hole (one insertion part)
57 Moving space 61 Second insertion hole (the other insertion part)
63 Stepped part (movement restriction member)
66 First sealing material (seal material on the discharge side)
67 Second sealing material (suction side sealing material)
69 Pushing member 71 Straight surface 72 Tapered surface 77 Movement restriction pin (movement restriction member)
79 Support member 93 1st insertion protrusion (insertion part)
97 2nd insertion protrusion (insertion part)
99 Stepped part (movement restriction member)
100 Movement limit screw (movement limit member)
101 1st sealing material 102 2nd sealing material 105a, 105b Movement restriction convex member (movement restriction member)
A Insertion / removal direction B Length direction C Insertion direction D Depth of suction side and discharge side insertion holes (depth of insertion part)
E Insertion dimension F1 Axial thrust

Claims (8)

Thrust balance with casing with fluid inlet and outlet, main shaft rotatably supported in casing, impeller mounted on main shaft, and balance piping to reduce axial thrust generated on main shaft A pump with a device,
The balance pipe is connected between the suction side member provided in the casing and communicating with the suction port side, the discharge side member provided in the casing and communicating with the discharge port side, and the suction side member and the discharge side member. Connecting pipes,
Each of the suction side member and the discharge side member has an insertion part that is inserted with an end of the connection pipe and sealed with a sealing material,
One of the suction side member and the discharge side member has a moving space that allows the connecting pipe to move in the length direction after the assembly of the balance pipe. When the connection pipe is moved by the moving space,
The pump according to claim 1, wherein the connection pipe is removable from the other insertion part different from the one insertion part having the moving space. The pump according to claim 1 or 2, wherein the insertion portion having the moving space is provided in the discharge side member. The pump according to any one of claims 1 to 3, further comprising a movement restriction member that restricts movement of the connection pipe in the length direction after the balance pipe is assembled. The insertion part is an insertion hole,
The end of the connection pipe is inserted into the sealing material,
The sealing material is inserted between the outer peripheral surface of the end portion of the connection pipe and the inner peripheral surface of the insertion hole, and is formed in an annular shape having a thin wedge-shaped cross section at the distal end portion in the insertion direction. Being pressed,
Formed on the inner periphery of the sealing material are a straight surface that is located on the distal end side in the insertion direction and has a constant inner diameter, and a tapered surface that gradually increases in diameter from the straight surface toward the base end on the side opposite to the insertion direction. The pump according to any one of claims 1 to 4, wherein the pump is provided. The discharge side member is removably inserted into the discharge side insertion portion formed in the casing,
The pump according to any one of claims 1 to 5, wherein a support member that supports the balance pipe is provided in the casing. The suction side member is removably inserted into the suction side insertion portion formed in the casing,
The insertion / removal direction of the suction side member with respect to the suction side insertion portion and the insertion / removal direction of the discharge side member with respect to the discharge side insertion portion are the same direction,
The support member supports the balance pipe so as to limit movement in the insertion / removal direction,
The depth of the suction side insertion part is deeper than the insertion dimension of the suction side member to the suction side insertion part,
7. The pump according to claim 6, wherein the depth of the discharge side insertion portion is formed deeper than the insertion dimension of the discharge side member into the discharge side insertion portion. A method for assembling the pump according to any one of claims 1 to 7,
Install the impeller on the main shaft,
An impeller integrated with the main shaft is rotatably mounted in the casing,
Attach the discharge side member to the casing,
Move the connection pipe to the discharge side and insert one end of the connection pipe into the insertion part of the discharge side member.
Move the connection pipe to the suction side, insert the other end of the connection pipe into the insertion part of the suction side member provided in the casing,
Assembling the pump characterized by sealing with a sealing material between one end of the connection pipe and the insertion part of the discharge side member and between the other end of the connection pipe and the insertion part of the suction side member. Method.

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