NL1044289B1

NL1044289B1 - Engageable and disengageable shaft seal assembly

Info

Publication number: NL1044289B1
Application number: NL1044289A
Authority: NL
Inventors: Adrianus Johannes Luksenburg Jonathan
Original assignee: Marflex Holding B V
Priority date: 2022-04-05
Filing date: 2022-04-05
Publication date: 2023-10-25

Abstract

ENGAGEABLE AND DISENGAGEABLE SHAFT SEAL ASSEMBLY Contrary to mechanica! seals that have to be operational, i.e. have to seal the shaft of a pump, continuously, the seal assembly according to the present disclosure is configured to be engaged and disengaged at will, to enable the use of its sealing function only for example during certain maintenance activities on the pump. The seal according to the invention can be engaged and disengaged both when a shaft is stationary or white it is moving. The seal assembly according to the invention also includes embodiments for continuous operation.

Description

ENGAGEABLE AND DISENGAGEABLE SHAFT SEAL ASSEMBLY

FIELD OF THE INVENTION

The present disclosure relates generally to seals for pump shafts, and particularly to shaft seals that don't need to be operational continuously and, hence, can be switched easily from a disengaged to an engaged status and vice versa,

BACKGROUND OF THE INVENTION

Mechanical seals are generally used to prevent liquid from escaping along a rotating or reciprocating shaft of a pump or other type of relevant equipment. In this respect, hereinafter, the term pump shall be construed 10 also cover any other type of equipment for which sealing of a moving part may be necessary or desirable. Centrifugal pumps and positive displacement pumps comprise a moving, which usually comprises rotating or translating, shaft while mechanically containing and maintaining fluid or gas on the ‘wet side’ of the pump. This type of mechanical seals need to perform their sealing function continuously when the pump is in operation. As a result of this, the sealing components of mechanical seals tend to be prone to a significant degree of wear,

BRIEF DESCRIPTION OF THE INVENTION

Contrary to mechanical seals that have to be operational, le. have to seal the shaft of a pump, continuously, the seal according to the present disclosure is configured to be engaged and disengaged at will, to enable the use of its sealing function only for example during certain maintenance activities on the pump. The seal according to the invention can be engaged and disengaged both when a shaft is stationary or while itis moving.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be better understood from reading the following description of non-limiting embodiments, with reference to the attached schematic drawings, wherein: - Fig. 1is a perspective top view of an embodiment of the seal according to the invention in the disengaged or deactivated status; - Fig. 2.15 a perspective view of an embodiment of the seal according to the invention in an engaged or activated status; - Fg 3 ís a vertical cross section through some of the components of an embodiment of the seal according to the invention in the disengaged status; - Fig. is a vertical cross section through some of the components of an embodiment of the seal according to the invention in the engaged status; - Fig. 5is a vertical cross section through the center of an embodiment of the seal according to the invention in the disengaged status; - Fig. 61s 3 vertical cross section through the center of an embodiment of the seal according to the invention in the engaged status.

In the drawings identical or similar parts have been given identical or similar reference numbers.

DETAILED DESCRIPTION QF THE INVENTION

A few embodiments of the sealing method and device according to the invention will now be described in detail with reference to the attached drawings.

Fig. 1 is a perspective top view of an embodiment of the seal according to the invention in the disengaged or deactivated status. In the present context the term “disengaged” shall be construed to mean not in the position to actually perform its sealing task, while

‘engaged’ shall be construed to mean the opposite. This embodiment of the seal assembly comprises a cylindrical upper sleeve 2 positioned directly around the drive shaft 1 of a pump.

The seal cylinder 3 comprises two stubs 31a and 31b, also referred to as shaft ends, that protrude essentially radially outward on opposite sides of the seal cylinder 3. The first stub 31a engages with the first cam 6a and the second stub 31b engages with the second cam 6b of a tilting cam assembly comprising these two cams and a cam connecting shaft 61 between these cams. Tilting of the cam assembly is done by moving a translating lever 8 outwards. In various embodiments of the seal according to the invention the translating lever 8 comprises external threading that engages with internal threading of the translating lever housing 9 and which is configured to result in a translating movement of the translating lever when the hexagonal head 10 of the translating lever is rotated. in order to engage with the translating lever, the first cam 6a comprises a lug 62 with a slot that engages with the translating lever 8. For this reason this first cam 6a may also be referred to as the driven cam 6a. All the parts described above are located inside or at the periphery of the main seal housing 7. In several embodiments of the seal assembly according to the invention, the translating movement of the translating member 8 can be accomplished by hand without or with the use of one or more hand tools,

Fig. 2 is a perspective top view of an embodiment of the seal according to the invention in an engaged status, The fact that the seal as shown in Fig. 2 is In the engaged position is immediately clear by looking at the position of the head 10 of the translating lever 8. In this position, the translating lever extends well outside the periphery of the main seal housing 7. This provides a readily observable tell-tale indication of the status of the seal according to the invention and is one of its unigue characteristics.

As can be seen in Fig. 2 the cam 6a comprises a curved elongated slot which forces the first stub 31a to move upward when the first cam Ga is tilted, Thanks to the connector 61 the second cam 8b moves in sync with the first cam and forces the second stub 31b to move upward in sync with the first stub 31a. Upward movement of the first and the second stubs 31a and 31b results in upward movement of the seal cylinder 3 which is a required movement for the seal to be activated, i.e. engaged.

Fig. 3 is a schematic vertical cross section through some of the components of an embadiment of the seal according to the invention in the disengaged position, Fig. 3 8 provides a clear view of the tilting mode of the cam assembly. Furthermore it schematically shows the engagement of the translating lever 8 with the lug 62 and the way the translating lever 8 is engaged with the translating lever housing 2.

Fig. 4 is a schematic vertical cross section through some of the components of the embodiment of the seal according to the invention as shown in Fig. 3, but now in the engaged position. The cam 6a has been tilted around the cam connecting shaft 61 counterclockwise almost to the maximum, which caused the stub 314 to be pushed close to its top position. The translating lever protrudes outwards, which in this context shall mean outside the periphery of the main body of the housing 7 of the seal.

Fig. 5 is a schematic vertical cross section through the center of an embodiment of the seal according to the invention in the disengaged status and Fig. 6 is a schematic vertical cross section through the center of the same embodiment of the seal according to the invention in the engaged position. Along its inner circumference the upper sleeve 2 comprises a groove to receive a sealing element, for example an O-ring, that provides the actual sealing of the crevice between the shaft and the upper sleeve. The seal assembly further comprises a seal cylinder 3 with a groove along its inner circumference to accommodate a sealing element, for example an O-ring. When the seal cylinder is moved axially to its top position the latter O-ring or other type of internal sealing element of the seal cylinder, provides a seal between the outer surface of the upper sleeve 2 and the inner surface of the seal cylinder 3. The seal cylinder 3 is, at least partially, surrounded by a cylinder housing 5. The seal cylinder further comprises an internal sealing element, for example an O-ring in the vicinity of its lower end, which provides a seal between the outer surface of the bottom sleeve 4 and the inner surface of the seal cylinder 3.

The invention envisages that the sealing elements that are used in the seal assembly according to the invention can comprise for example elastomeric components, such as for example rubber O-rings, or sealing elements made of for example a carbon-graphite composite or any other suitable material depending on the required wear resistance for a 5 specific application.

As can be seen the difference between the engaged and disengaged condition comprises essentially the position of the seal cylinder 3. In the engaged status as shown in Fig. 6 the seal cylinder 3 has been moved to essentially its top position, whereby the two seals on the inner surface of the seal cylinder 3 surround and seal respectively the outer surfaces of the upper sleeve 2 and the lower sleeve 4 of the seal according to the invention. The seal cylinder 3 ís moved up or down by tilting the cam assembly which in turn forces the stubs 31a and 31b of the seal cylinder 3 to move up or down, In the embodiment of the lower sleeve 4 shown in Fig. 5 and Fig. 6 the lower end of the lower sleeve is tapered.

As described above, the invention may especially be embodied in the following embodiments, wherein the embodiments are merely numbered for reference reasons. 1. A method of sealing a moving shaft by using a seal assembly, wherein, the seal assembly comprises measures that enable switching the seal assembly from a disengaged status to and engaged status and back by translating a lever of the seal assembly that is accessible from the exterior of the seal assembly. 2. The method according to embodiment 1, wherein, the translation of the lever can be effectuated by hand with or without the use of a hand tool. 3. The method according to embodiment 1 or 2, wherein, the method includes providing a tell-tale sign regarding the sealing status of the seal assembly which tell-tale sign is readily observable by looking at the exterior of the seal assembly. 4. The method according to embodiment 3, wherein, the tell-tale sign comprises whether or not the control lever extends beyond the periphery of the main seal housing.

S. An engageable and disengageahle shaft seal assembly, wherein, the seal assembly comprises a cylindrical upper sleeve {2} and a cylindrical lower sleeve {4} that are configured to be mounted on a shaft and a seal cylinder {3} that can be moved axially along the outer surfaces of the upper and lower sleeve. 6. The shaft sea! assembly according to embodiment 5, wherein, two sealing elements along the internal circumference of the seal cylinder {3} form a sealed connection between the internal surface of the seal cylinder and the external surface of respectively the upper sleeve {2} and the lower sleeve (4) when the shaft seal assembly is in the engaged status, 7. The shaft seal assembly according to embodiment 5 or 6, wherein, the seal cylinder {3} comprises two stubs {314,31b} on opposite spots of its external surface and each of these stubs protrudes into a slot In one of two cams {624,60} which cams are mutually connected by a carn connecting shaft {61} and tiltable around this shaft. &. The shaft seal assembly according to embodiment 7, wherein, the seal assembly further comprises a translating lever {8} configured to engage with a slot in a lug {62} on the first cam {6a). 8. The shaft sealing assembly according to any of the embodiments 6-8, wherein, external threading on the translating lever {8} is configured to engage with internal threading in a translating lever housing (9).

The term “comprise” includes also embodiments wherein the term “comprises” means “consists of”. The term “and/or” especially relates to one or more of the items mentioned before and after “and/or”. For instance, a phrase “item 1 and/or item 27 and similar phrases may relate to one or more of item 1 and item 2. The term “comprising” may In an embodiment refer to "consisting of" but may in another embodiment also refer to “containing at least the defined species and optionally one or more other species”.

While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled In the art. It is,

therefore, to be understood that the appended claims are intended to cover all such madifications and changes as fall within the true spirit of the invention, it should be noted that the above-mentioned embodiments illustrate rather than mit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. in the clainss, any reference signs placed between parentheses shall not be construed as imiting the claim. Use of the verb "to comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

CONCLUSIONS i. A method of sealing a moving shaft with a sealing assembly, characterized in that the sealing assembly comprises measures which enable the sealing assembly to be converted from the non-activated state to the activated state and vice versa by moving it in the axial direction of a handle of the sealing assembly, which handle is accessible from the outside of the sealing assembly.

2. The method according to claim 1, characterized in that the axial displacement of the handle can be realized manually, with or without the use of hand tools.

The method according to claim 1 or 2, characterized in that the method comprises an indicator regarding the sealing condition of the sealing assembly which is clearly visible on the outside of the sealing assembly.

The method according to claim 3, characterized in that the indicator comprises whether or not the handle protrudes beyond the outer contours of the housing of the sealing assembly.

5. A switchable and switchable shaft sealing assembly, characterized in that the sealing assembly comprises a cylindrical upper housing {2} and a cylindrical lower sleeve {4} which are adapted to be mounted on a shaft and a sealing cylinder (3) which is movable in axial direction over the outer surface of the upper housing and lower sleeve.

The shaft seal assembly according to claim 5, characterized in that two sealing elements located in the internal surface of the sealing cylinder {3} form a sealing connection between the internal surface of the sealing cylinder and the external surface of the upper housing (2) respectively. ) and the lower sleeve {4} when the shaft seal assembly is in the activated condition.

7. The shaft sealing assembly according to claim 5 or 6, characterized in that the sealing cylinder {3} comprises on either side a shaft end (318, 31b) protruding in the radial direction, the end of each of these shaft ends being located in a slot in one of two cams (623,6b} and where the two cams are mutually connected by a connecting axis {61} and can be tilted about this connecting axis.

The shaft seal assembly according to claim 7, characterized in that the seal assembly further comprises a handle {8} which is adapted to connect to a lip {62} present on a first cam (6a).

9. The shaft sealing assembly according to one or more of claims 6-8, characterized in that the handle (8) comprises external screw thread which is adapted to cooperate with internal screw thread in a housing {9) present in the shaft sealing assembly. } for the lever (8).