Mechanical seal for sanitary centrifugal pump

Abstract

The invention discloses a mechanical seal for a sanitary centrifugal pump. The mechanical seal comprises a static ring assembly, a movable ring assembly, an elastic assembly and a driving seat (1), the sealing end face of the static ring (5) is provided with a first sealing end (7) and a second sealing end (8), the second sealing end (8) is provided with a first plane with a plurality of recesses (9), the recesses (9) are used for storing fluid media, and the first sealing end (7) is a second plane; in the working state and the state that the medium does not reach the sealing surface of the static ring (5) and the movable ring (4), the medium stored in the recess (9) of the second sealing end (8) enables the first plane and the movable ring (4) to realize liquid sealing, and the first sealing is tightly attached to the sealing surface of the movable ring (4); the mechanical seal solves the problem of abrasion caused by dry friction of a sealing surface during high-speed starting, improves the sealing performance and prolongs the service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical seal, in particular to a mechanical seal for sanitary centrifugal pump. BACKGROUND

[0002] At present, remote speed control is generally used for sanitary pump, and the starting speed of pump body is much faster than the conveying speed of medium, which results in that the medium has not reached the sealing end face when the pump is running, forming dry friction state without lubrication and cooling, and seriously shortening the service life of the seal. The sealing end face of conventional static ring and dynamic ring is mostly flat or simple groove type (such as trapezoidal groove, dovetail groove), and the friction resistance and lubrication effect are difficult to balance, and there is lack of design for high-speed dry friction working condition.

[0003] In addition, in the contact of mechanical seal end face, especially under low load conditions, the contact between surfaces can be approximated as the contact of multiple micro-convex bodies. This low stress contact condition often leads to the problems of small actual contact area and large contact pressure of single micro-convex body. When the seal ring is running, these small contact points will generate high temperature in the friction process, because the heat is only released on the small contact points. The temperature rise of these small contact points can be as high as several hundred degrees Celsius, and the duration is only a few microseconds. This phenomenon is called "flash temperature", because it only appears on a very small area, it may cause local thermal damage and surface damage of the seal ring, thereby affecting the sealing performance and service life. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a mechanical seal for sanitary centrifugal pump, which solves the problem of wear caused by dry friction of sealing surface during high-speed starting, and improves the sealing performance and service life.

[0005] The technical scheme of the present application is to provide a mechanical seal for a sanitary centrifugal pump, which has the following structure: a static ring assembly, a dynamic ring assembly, an elastic assembly and a driving seat; the driving seat is sleeved on the outer shaft and is axially positioned against the annular step surface of the shaft and is circumferentially positioned with the shaft by a positioning pin to rotate synchronously; the dynamic ring assembly is sleeved on the outer shaft and is circumferentially positioned with the other end of the driving seat to rotate synchronously, and the dynamic ring assembly and the driving seat have a sliding structure in the axial direction; the elastic assembly is sleeved on the outer dynamic ring assembly and the driving seat and pushes the dynamic ring assembly and the static ring assembly to be close to each other; the static ring assembly is sleeved on the outer shaft and is spaced from the outer wall of the shaft; the dynamic ring assembly comprises a dynamic ring, and the static ring assembly comprises a static ring and a static ring seat, characterized in that: the sealing end surface of the static ring is provided with a first sealing end and a second sealing end, the second sealing end is provided with a plurality of recessed first planes, the recesses are used to store fluid medium, and the first sealing end is a second plane; in the static state, the first plane, the second plane of the static ring and the sealing end surface of the dynamic ring are close to each other under the pushing of the elastic assembly; in the working state and when the medium does not reach the sealing surface of the static ring and the dynamic ring, the medium stored in the recesses of the second sealing end makes the first plane and the dynamic ring realize liquid sealing, and the first sealing end is close to the sealing surface of the dynamic ring; in the working state and when the medium reaches the sealing surface of the static ring and the dynamic ring, the recesses of the second sealing end supplement new medium to fill up, and the first plane, the second plane and the dynamic ring realize liquid sealing.

[0006] The medium passing through the first plane, the second plane and the sealing surface of the dynamic ring is evaporated by the heat generated by the friction of the sealing surface, avoiding entering the inside of the mechanical seal.

[0007] The recesses have a micropore structure, the micropore depth is 0.08-0.12mm, and the radius is 0.04-0.06mm.

[0008] The stored medium in the recesses of the second sealing end exchanges heat with the friction pair of the dynamic ring and the static ring, which is used to reduce the temperature generated by the dry friction of the friction pair of the dynamic ring and the static ring in the starting state.

[0009] The first sealing end has an annular structure, the second sealing end also has an annular structure, the annular structure of the first sealing end and the annular structure of the second sealing end are coaxial, and the second sealing end is located on the inner side of the first sealing end.

[0010] The static ring is installed in the center hole of the static ring seat in an axial floating structure.

[0011] The outer wall of one end of the static ring located on the sealing end surface is provided with an annular step, and the annular step is provided with a sealing gasket and an end seal.

[0012] After the above structure is adopted, the present application has the following advantages:

[0013] 1. The recessed planes can store a portion of the fluid medium when the pump is stopped. In the initial stage of pump starting, the stored medium is released to form a temporary lubricating film between the sealing surfaces, realizing seamless sealing transition from starting to normal medium delivery, avoiding the serious wear caused by dry friction in the starting moment of traditional seals.

[0014] 2. Since the sealing surface of the static ring has a first sealing end and a second sealing end, and the second sealing end is provided with a plurality of recessed first planes, the recesses are used to store fluid medium, so that in the initial stage of pump starting, the medium has not reached the sealing surface, the medium in the recess can play a role of liquid seal and cooling, thereby supplementing the dry seal during the time when the medium reaches the sealing surface, and the medium in the recess can effectively reduce the dry seal during this period. The problem of "dry friction" or "boundary friction" caused by the fact that the medium has not filled the sealing cavity to form a lubricating liquid film when the pump is just started is effectively solved.

[0015] 3. The medium stored in the recess can effectively reduce the temperature of the micro-convex points of the friction pair, thereby reducing friction and wear. Under the action of the micro-holes, the temperature change trend of the surface of the friction pair is the same as the change trend of the contact area, so that the "hot spot" temperature of the micro-convex body of the friction pair is relatively uniform, and the thermal damage of the end surface caused by temperature rise is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a sectional view of the mechanical seal for the sanitary centrifugal pump of the present application.

[0017] Figure 2 is a sectional view of the static ring of the present application.

[0018] Figure 3 is a front view of the static ring of the present application.

[0019] Figure 4 is an enlarged view of part A of Figure 3 .

[0020] Figure 5 is a connection diagram of the static ring and the static ring seat.

[0021] The drawings show:

[0022] 1. Drive seat, 2. Shaft, 3. Positioning pin, 4. Dynamic ring, 5. Static ring, 6. Static ring seat, 7. First sealing end, 8. Second sealing end, 9. Recess. DETAILED DESCRIPTION

[0023] The present application will be further described below in conjunction with the drawings.

[0024] For example, Figures 1-5As shown, the mechanical seal for sanitary centrifugal pump of the present application comprises a static ring assembly, a dynamic ring assembly, an elastic assembly and a driving seat 1; the driving seat 1 is sleeved outside the rotating shaft 2, and one end is axially positioned against the annular stepped surface of the rotating shaft 2 and synchronously rotates with the rotating shaft 2 through the positioning pin 3, the dynamic ring assembly is sleeved outside the rotating shaft 2 and one end is circumferentially positioned against the other end of the driving seat 1 and synchronously rotates, and the dynamic ring assembly and the driving seat 1 have a sliding structure in the axial direction, the elastic assembly is sleeved outside the dynamic ring assembly and the driving seat 1 and pushes the dynamic ring assembly and the static ring assembly to be close to each other, and the static ring assembly is sleeved outside the rotating shaft 2 and has a spacing with the outer wall of the rotating shaft 2; the dynamic ring assembly comprises a dynamic ring 4, and the static ring assembly comprises a static ring 5 and a static ring seat 6.

[0025] As shown in Figure 2 and Figure 3 As shown, the sealing end face of the static ring 5 is provided with a first sealing end 7 and a second sealing end 8, the second sealing end 8 is provided with a first plane of a plurality of recesses 9, and the recesses 9 are used for storing fluid medium, and the first sealing end 7 is a second plane.

[0026] The first sealing end 7 is in an annular structure, the second sealing end 8 is also in an annular structure, the annular structure of the first sealing end 7 and the annular structure of the second sealing end 8 are coaxial, and the second sealing end 8 is located on the inner side of the first sealing end 7. The first sealing end 7 and the second sealing end 8 are located on one end face of the static ring 5. The first sealing end 7 is located on the outer side, and the second sealing end 8 is located on the inner side.

[0027] The second sealing end 8 is provided with a first plane of a plurality of recesses 9, and the recesses 9 are used for storing fluid medium, which means that the recesses 9 are in a micropore structure, the micropore depth is 0.08-0.12mm, and the radius is 0.04-0.06mm, and the micropore depth of the embodiment is preferably 0.01mm and the radius is 0.05mm.

[0028] The working principle of the mechanical seal for sanitary centrifugal pump of the present application is as follows:

[0029] In the static state, the first plane and the second plane of the static ring 5 are close to the sealing end face of the dynamic ring 4 under the pushing of the elastic assembly, at this time the dynamic ring 4 has not started to rotate, and the sealing end face of the dynamic ring 4 is close to the sealing end face of the static ring 5. All or part of the recesses 9 on the first plane of the static ring 5 store the medium left over from the previous work, and since the sealing end face of the dynamic ring 4 is close to the sealing end face of the static ring 5, the medium in the recesses 9 is in a sealed or closed environment and will not evaporate and disappear within a period of time.

[0030] In the working state and the medium does not reach the sealing surface state of the static ring 5 and the dynamic ring 4, at this time the pump has been running, the dynamic ring 4 has been rotated, and the medium has not reached the sealing surface. At this time, the medium stored in the recess 9 of the second sealing end 8 makes the first plane and the dynamic ring 4 achieve liquid sealing, and the first sealing and the sealing surface of the dynamic ring 4 are in close contact.

[0031] In the working state and the medium reaches the sealing surface state of the static ring 5 and the dynamic ring 4, the recess of the second sealing end 8 is filled with new medium, and the first plane, the second plane and the dynamic ring 4 achieve liquid sealing.

[0032] The medium passing through the sealing surface of the first plane, the second plane and the dynamic ring 4 is evaporated by the heat generated by the friction of the sealing surface, avoiding entering the inside of the mechanical seal.

[0033] The stored medium in the recess 9 of the second sealing end 8 exchanges heat with the friction pair of the dynamic ring 4 and the static ring 5, which is used to reduce the temperature generated by the dry friction of the friction pair of the dynamic ring 4 and the static ring 5 in the starting state.

[0034] The static ring 5 is installed in the center hole of the static ring seat 6 in an axial floating structure. The outer wall of the static ring 5 located at one end of the sealing end face is provided with an annular step, and the annular step is provided with a sealing gasket and an end seal.

Claims

1. A mechanical seal for sanitary centrifugal pumps, comprising a static ring assembly, a dynamic ring assembly, an elastic assembly and a driving seat (1); the driving seat (1) is sleeved outside the rotating shaft (2) and is axially positioned against the annular stepped surface of the rotating shaft (2) at one end and is synchronously rotated with the rotating shaft (2) through the circumferential positioning of the positioning pin (3), the dynamic ring assembly is sleeved outside the rotating shaft (2) and is synchronously rotated with the other end of the driving seat (1) through the circumferential positioning, while the dynamic ring assembly and the driving seat (1) have a sliding structure in the axial direction, the elastic assembly is sleeved outside the dynamic ring assembly and the driving seat (1) and pushes the dynamic ring assembly and the static ring assembly to be close to each other, and the static ring assembly is sleeved outside the rotating shaft (2) and is spaced from the outer wall of the rotating shaft (2); the dynamic ring assembly comprises a dynamic ring (4), and the static ring assembly comprises a static ring (5) and a static ring seat (6), characterized in that: The sealing end face of the static ring (5) is provided with a first sealing end (7) and a second sealing end (8), the second sealing end (8) is provided with a first plane with a plurality of recesses (9) for storing fluid medium, and the first sealing end (7) is a second plane; In the static state, the first plane and the second plane of the static ring (5) are tightly attached to the sealing end face of the dynamic ring (4) under the pushing of the elastic assembly; In the working state and when the medium does not reach the sealing face of the static ring (5) and the dynamic ring (4), the medium stored in the recess (9) of the second sealing end (8) makes the first plane and the dynamic ring (4) achieve liquid sealing, and the first sealing end is tightly attached to the sealing face of the dynamic ring (4); In the working state and when the medium reaches the sealing face of the static ring (5) and the dynamic ring (4), the recess of the second sealing end (8) is filled with new medium, and the first plane and the second plane and the dynamic ring (4) achieve liquid sealing.

2. The mechanical seal for sanitary centrifugal pumps according to claim 1, characterized in that: The medium passing through the sealing face of the first plane, the second plane and the dynamic ring (4) is evaporated by the heat generated by the friction of the sealing face, avoiding entering the inside of the mechanical seal.

3. The mechanical seal for sanitary centrifugal pumps according to claim 1, characterized in that: The recess (9) is in a microporous structure, the micropore depth is 0.08-0.12mm, and the radius is 0.04-0.06mm.

4. The mechanical seal for sanitary centrifugal pumps according to claim 1, characterized in that: The stored medium in the recess (9) of the second sealing end (8) exchanges heat with the friction pair of the dynamic ring (4) and the static ring (5), which is used to reduce the temperature generated by the dry friction of the friction pair of the dynamic ring (4) and the static ring (5) in the starting state.

5. The mechanical seal for sanitary centrifugal pumps according to claim 1, characterized in that: The first sealing end (7) is in a ring structure, the second sealing end (8) is also in a ring structure, the ring structure of the first sealing end (7) and the ring structure of the second sealing end (8) are coaxial, and the second sealing end (8) is located inside the first sealing end (7).

6. The mechanical seal for sanitary centrifugal pumps according to claim 1, characterized in that: The static ring (5) is installed in the center hole of the static ring seat (6) in an axial floating structure.

7. The mechanical seal for sanitary centrifugal pumps according to claim 1, characterized in that: The outer wall of one end of the static ring (5) located at the sealing end face is provided with an annular step, and the annular step is provided with a sealing gasket and an end seal.

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