RU2679291C1 - Mechanical seal - Google Patents

Abstract

FIELD: sealing equipment.SUBSTANCE: invention relates to a sealing technique, in particular to mechanical seals intended for installation on hydraulic and pneumatic machines and devices, the working bodies of which perform a rotational and/or reciprocating motion. Mechanical seal of the shaft, or the plunger, or the stem, or the cylinder of the machine contains mounted in the cage with alternating sealing rings and discs between the two supports, ground to each other along the ends and pressed against the sealing surfaces by an elastic element. On the outer or inner surface of the yoke are made, in return for the rings, the mounting necks or eccentric bores, eccentric about the axis of the sealing surface, and the sealing rings are made with concentric cylindrical surfaces and are located on the mentioned necks or in the bores. Diameter of the seating surface of the disks on the holder is greater or less than the diameter of the neck or boring by the amount of double eccentricity, and the height is greater than the height of the rings. At the cage surface mating with each ring, at least one blind recess is made, on the end surface of the rings there are blind recesses with the possibility of forming with the recess of the cage a continuous deaf groove on the ends of the previously deformed spring placed in it. Cage can be made in the form of a sleeve with a collar, responsively made sealing surface, while the upper disk is designed to interact with the stop.EFFECT: invention improves the tightness of the mechanical seal.6 cl, 6 dwg

Description

The invention relates to a sealing technique, in particular to mechanical seals intended for installation on hydraulic and pneumatic machines and devices whose working bodies rotate and / or reciprocate.

A seal of a shaft or rod or cylinder is known, containing eccentric sealing rings located in an elastic cage (see A.S. USSR No. 391315, cells, pressed axially against each other and pressed against the sealing surfaces of the cylinder, rod or shaft of these elements in opposite directions) F16J 15/26, 1973).

In the known device, due to the uncertainty of the angular displacement of the pairs of rings, it is possible to arrange elements with the formation of gaps between them and the sealing surface. This leads to increased leakage through the seal.

A mechanical seal is known for a shaft, or a rod and a plunger, or a cylinder of a machine, comprising sealing rings installed in a cage between the stops, rubbed against each other at the ends, and pressed against the sealing surfaces by an elastic cage in opposite directions, while on the outer or inner surface of the elastic cage eccentrically arranged collars (necks) or respectively eccentrically located bores are made, and o-rings are made concentric with cylindrical surfaces and located s on the mentioned collars (necks) or in borings (see Pat. RF No. 2037077, MKP F16J 15/26, publ. 09.06.1995).

The eccentric arrangement of the sealing rings on the elastic cage makes it possible to almost completely eliminate the gap between the sealing surface and the rings, as well as to compensate for their wear in the radial direction by compressing the elastic cage.

A disadvantage of the known device is the significant dimensions of the seal in the diametrical direction due to the location between the sealing rings and the housing of the hydraulic machine or the piston body of the elastic element, made in the form of a pipe.

The technical result is achieved by the fact that in the mechanical seal of the shaft, or plunger, or rod, or cylinder of the machine, containing the sealing rings installed in the cage between the two supports, rubbed against each other at the ends and pressed against the sealing surfaces by an elastic element, on the outer or inner surface cages are made, in response to rings, eccentric landing rings or eccentric bores relative to the axis of the sealing surface, and o-rings are made with concentric cylindrical surfaces according to the technical solution, disks are installed between the sealing rings, the diameter of the seating surface of which is more than or less than the diameter of the neck or bore by an amount of double eccentricity, and the height is greater than the height of the rings, the inner holes of the rings are made with eccentricity, at the same time, at least one blind recess is made on the surface of the ring mating with the ring; blind recesses are made on the end surface of the rings with the possibility of reversal mations holder with a recess for the continuous blind groove with the ends disposed therein previously deformed springs.

The cage is made in the form of a sleeve with a shoulder, reciprocally made of the sealing surface, while the upper disk is made with the possibility of interaction with the focus.

The forming surfaces of the hollows of the cage and rings are made parallel with the formation of an acute angle with the radius of the cylinder and the placement in the grooves of a pre-pressed compression spring.

The spring is made in the form of a pre-deformed curved rod.

An annular groove is made on the surface of the holder mating with each ring, and annular grooves are formed in the rings corresponding to the grooves with the formation of an annular space with a twisted torsion spring placed.

The recesses in the ferrule and rings are made with the simultaneous formation of a solid groove at the ends of the groove and the interaction of the side surfaces of the rings with the sealing surface.

The design of the mechanical seal is illustrated in the drawing.

In FIG. 1 is a diagram of a borehole submersible pump with the proposed piston seal;

In FIG. 2 is a section AA in FIG. one;

In FIG. 3 - embodiment of the seal with compression springs;

In FIG. 4 - embodiment of a mechanical seal with twisted torsion springs;

In FIG. 5 is a section BB in FIG. four;

In FIG. 6 is a diagram of a double-acting cylinder pump with the proposed piston and rod seals.

A mechanical seal, for example a borehole submersible pump, contains o-rings 4, 5, 6 and 7 installed in the core 1 or in the piston holder 2 eccentrically relative to the axis of the holder 1 and cylinder 3, between these rings 4-7, and above the extreme upper ring 7, ground to the ends of adjacent o-rings, pressure plates 8-11. The lower ring 4 interacts with the shoulder 12 of the core 1.

The seating surfaces (not shown in FIG.) Of the core 1 for installing the sealing rings 4-7 are made in the form of collars or necks (not shown in FIG.) With an eccentricity “e” (FIG. 2) relative to the axis of the cylinder 3 with the same angular distance between radial lines passing through the axis of the cylinder 3 and rings 4-7. If the number of rings is n, then the angular distance between the indicated radial lines is 360 / n. The inner cylindrical hole of the rings 4-7 is also made with an eccentricity "e". The outer diameter of the rings 4-7 is equal to the diameter of the cylinder 3.

The inner diameter of the pressure plates 8-11 is larger than the inner diameter of the rings 4-7 and necks (not shown in FIG.) By at least twice the eccentricity “e”, that is, d _p > d _y + 2e (where d _p , d _y, respectively, the internal diameters of the pressure and sealing rings).

In the holder 1 of the piston 2, for example, blind radial recesses 13 are made on the upper part of the seating surface of the sealing rings 4-7. In the upper part of the rings 4-7, blind recesses 14 are open radially or at an angle to the radius of the rings, open from the side the seating surface to the clip 1. The recesses 13 and 14 are configured to form a single groove 15. In the grooves 15, preformed deformed springs 16 are mounted reciprocally with them to ensure that the lateral surface of the rings 4-7 is pressed against the sealing surface of the cylinder 3. The recesses 13 and 14 can be performed with the simultaneous formation of a single groove 15 and the interaction of the lateral surface of the rings with the sealing surface of the cylinder 3.

The upper pressure disk 11 can be fixed, for example, using a spring split ring 17, which can also be made spring in the axial direction.

The rings 4-7 can be equipped, for example, with radial sealing elements 18-21, and the core 1 of the piston 2 can be made with a central through hole 22 with an installed discharge valve 23, made, for example, in the form of a ball, and a seat 24. In the lower part of cylinder 2, a suction valve 25 is installed.

The piston in the upper part is connected to the actuator (not shown in FIG.) By means of a rod string 26.

The piston 2 is installed in the cylinder 3 with the formation of the working cavity 27, which through the discharge valve 23, the through hole 22 can be connected to the discharge cavity 28.

The forming surfaces of the recesses 13 (Fig. 3) of the holder 1 and the recesses 14 of the rings 4-7 can be made parallel with the formation of an acute angle a with the radius of the cylinder. In the grooves 15 formed by the recesses 13 and 14 are placed pre-pressed compression springs 29. In this case, the distance from the axis of the cylinder 3 to the axis of the spring 29, which is the shoulder of the force of the spring 29, is R. Thanks to the shoulder R, torque arises from the force of the spring 29.

In the cage 1 (Fig. 4) of the piston 2, for example, on the upper part of the seating surface of the sealing rings 4-7, annular grooves 30 can be made, the depth of which is less than the depth of the radial recesses 13. In the upper part of the rings 4-7, corresponding to the grooves 30, ring grooves 31 are made with a torsion spring 32 located therein. The recesses 13 and 14 (Fig. 5) of the housing 1 and rings 4-7 are made in response to the end sections (not shown in Fig.) Of the torsion spring 32 with the possibility of rotation of the rings 4-7 relative to the axis of the cage 1 with the possibility of interaction of the rings 4-7 with the sealed cylinder surface 3.

The proposed mechanical seal may be equipped with a rod 33 (Fig. 6) and a piston 34 of a cylinder 35 of a double-acting pump.

For example, a core 37 with a collar 38 of a piston 34 with sequentially arranged sealing rings 39 and pressure discs 40 is installed on the stem 33 with a collar 36. The rings 39 are mounted with an eccentricity relative to the axis of the cylinder 35, while the inner hole of the rings 39 is also made with the same eccentricity relative to the outer diameter. The rings 39 with the core 37 are provided with a pre-deformed spring 16, made, for example, in the form of a pre-bent rod of round or rectangular cross section, with the possibility of tight interaction of a part of the side surface of the rings 39 with the sealing surface of the cylinder 35. The rings 39 and pressure discs 40 are installed between the shoulder 38 core 37 and the upper stop 41, interacting with the upper disk 40. The stop 41 is made, for example, in the form of a nut.

The core 37 of the piston 34 on the rod 33 is fixed by a stop 42, made, for example, in the form of a split ring.

In the cylinder 35 on the drive side (not shown in FIG.), A cylindrical recess 43 is made with a collar 44, in which a sealing device is located, including a housing 45 with a collar 46 with sealing rings 47 and pressure plates 48 installed in series. The rings 47 and the housing 45 are provided pre-deformed spring 16, made, for example, in the form of a bent rod.

The upper pressure disk is fixed by a stop 49 made, for example, in the form of a spring split ring. Case 45 is pressed against shoulder 44 by cover 50.

The piston 34 is installed in the cylinder 35 with the formation of the piston 51 and rod 52 cavities, which are equipped with suction 53, 54 and pressure 55, 56 valves.

Mechanical seal assembly

In connection with the location of the axes of the seating surfaces in the core 1 (Fig. 1) with the same angular distance from each other, the lower sealing rings 4-6 are passed through the upper landing surfaces by rotating the rings. After combining the recesses 13 and 14 in the cage 1 and rings 4-7, pre-deformed springs 16 are installed in the slots 15. Under the action of the force of the springs 16, the rings 4-7 are rotated about their axis until they interact with the surface of the cylinder 3.

On top of each ring 4-7 are installed pressure plate 8-11. The fixing of the upper pressure plate 11 is carried out, for example, by a spring split ring 17.

The assembly of the mechanical seal with the compression spring 29 (Fig. 3), torsion 32 (Fig. 4, 5), as well as the piston 34 (Fig. 6) and the rod 33 of the double-acting pump is carried out in a similar way.

Mechanical seal operates as follows.

When installing a mechanical seal in the cylinder 3 of the pump (Fig. 1), the sealing rings 4-7 are pressed against the sealing surface of the cylinder 3 by means of springs 16 (Fig. 2). In places where the rings are pressed 4-7 gap gap is zero. The coverage angle with almost zero clearance is ϕ.

On the opposite side from the point of contact, the slot gap is maximum. However, due to the fact that the bores in the rings 4-7 and the seating surfaces of the rings in the housing 1 are made eccentric, and the rings at the ends are tightly pressed against the disks 8-11, and the axes of the eccentrically mounted rings are at the same angular distance from each other, almost the entire seal the surface of the cylinder 3 is overlapped by rings without a gap. The hydraulic resistance in the seal gap also increases due to the fact that the fluid flow passing through the gap repeatedly changes its direction. The installed springs 16 (Fig. 1, 2) constantly press the O-rings 4-7 against the sealing surface of the cylinder 3. The clearance in the working seal is gradually reduced due to the running-in of the rubbing surfaces of the rings 4-7 and the sealing surface of the cylinder 3. With wear of the rubbing surfaces of the spring 16 additionally rotate the rings 4-7 until they fit snugly against the sealing surface.

Thus, increased sealing tightness is achieved with a simultaneous increase in its service life.

The invention can be used in pumps, compressors, mixers, valves, in hydraulic and pneumatic devices and other machines and devices operating under excessive pressure.

When equipping the seal with compression springs 29 due to the formation of a shoulder R relative to the axis of the cylinder 3, the disks 4-7 are pressed against the surface of the cylinder 3.

The seal operation in FIG. 4 and 5 are similar to those described above. Installed torsion springs 32 constantly press the disks 4-6 against the sealing surface of the cylinder 3.

The operation of the sealing devices of the piston and rod (Fig. 6) of the double-acting pump is similar to that described above.

O-rings 39 of the piston 34 are pressed against the surface of the cylinder 35. In this case, each ring 39 seals a part of the surface of the cylinder 35.

O-rings 47 of the rod 33 are pressed by a spring 16 to the surface of the rod 33.

The mechanical seal design for the rotary shaft is similar to the stem sealing device (FIG. 6).

The advantage of the proposed seal is the almost constant friction force of the sealing rings on the sealing surface of the cylinder, plunger, rod or shaft, which is determined by the force of the springs.

With operating time, the tightness of the mechanical seal increases due to the running-in surface of the sealing rings and the reduction of the gap between the sealing rings and the sealing surface. The rotation and constant contact of the sealing rings due to the force of the springs provide compensation for the wear of the sealing rings and the sealing surface.

The upper pressure disk 11 can be fixed, for example, using a spring split ring 17 ,. ' which can also be spring-loaded in the axial direction.

The rings 4-7 can be equipped, for example, with radial sealing elements 18-21, and the core 1 of the piston 2 can be made with a central through hole 22 with an installed discharge valve 23, made, for example, in the form of a ball, and a seat 24. In the lower part of cylinder 2, a suction valve 25 is installed.

The piston in the upper part is connected to the actuator (not shown in FIG.) By means of a rod string 26.

The piston 2 is installed in the cylinder 3 with the formation of the working cavity 27, which through the discharge valve 23, the through hole 22 can be connected to the discharge cavity 28.

The forming surfaces of the recesses 13 (Fig. 3) of the holder 1 and the recesses 14 of the rings 4-7 can be made parallel with the formation of an acute angle a with the radius of the cylinder. In the grooves 15 formed by the recesses 13 and 14 are placed pre-pressed compression springs 29. In this case, the distance from the axis of the cylinder 3 to the axis of the spring 29, which is the shoulder of the force of the spring 29, is R. Thanks to the shoulder R, torque arises from the force of the spring 29.

In the cage 1 (Fig. 4) of the piston 2, for example, on the upper part of the seating surface of the sealing rings 4-7, annular grooves 30 can be made, the depth of which is less than the depth of the radial recesses 13. In the upper part of the rings 4-7, corresponding to the grooves 30, ring grooves 31 are made with a torsion spring 32 located therein. The recesses 13 and 14 (Fig. 5) of the housing 1 and rings 4-7 are made in response to the end sections (not shown in Fig.) Of the torsion spring 32 with the possibility of rotation of the rings 4-7 relative to the axis of the cage 1 with the possibility of interaction of the rings 4-7 with the sealed cylinder surface 3.

The proposed mechanical seal may be equipped with a rod 33 (Fig. 6) and a piston 34 of a cylinder 35 of a double-acting pump.

For example, a core 37 with a collar 38 of a piston 34 with sequentially arranged sealing rings 39 and pressure discs 40 is installed on the stem 33 with a collar 36. The rings 39 are mounted with an eccentricity relative to the axis of the cylinder 35, while the inner hole of the rings 39 is also made with the same eccentricity relative to the outer diameter. The rings 39 with the core 37 are provided with a pre-deformed spring 16, made, for example, in the form of a pre-bent rod of round or rectangular cross section, with the possibility of tight interaction of a part of the side surface of the rings 39 with the sealing surface of the cylinder 35. The rings 39 and pressure discs 40 are installed between the shoulder 38 core 37 and the upper stop 41, interacting with the upper disk 40. The stop 41 is made, for example, in the form of a nut.

The core 37 of the piston 34 on the rod 33 is fixed by a stop 42, made, for example, in the form of a split ring.

In the cylinder 35 on the drive side (not shown in FIG.), A cylindrical recess 43 is made with a collar 44, in which a sealing device is located, including a housing 45 with a collar 46 with sealing rings 47 and pressure plates 48 installed in series. The rings 47 and the housing 45 are provided pre-deformed spring 16, made, for example, in the form of a bent rod.

Claims (6)

1. The mechanical seal of the shaft, or plunger, or rod, or cylinder of the machine, containing the sealing rings installed in the cage between two bearings, rubbed against each other at the ends and pressed against the sealing surfaces by an elastic element, are made on the outer or inner surface of the cage in response to the rings eccentric bores or eccentric bores eccentric with respect to the axis of the sealing surface, and the o-rings are made with concentric cylindrical surfaces and are located on said necks and in bores, characterized in that disks are installed between the sealing rings, the diameter of the seat surface of which is more or less than the diameter of the neck or bore by the amount of doubled eccentricity, and the height is greater than the height of the rings, the inner holes of the rings are made with eccentricity, while each ring of the surface of the cage has at least one blind recess, on the end surface of the rings there are made blind recesses with the possibility of forming a continuous deaf with the hollow of the cage of the groove with the ends disposed therein previously deformed spring. 2. The seal according to claim 1, characterized in that the cage is made in the form of a sleeve with a shoulder, reciprocally made of the sealing surface, while the upper disk is made with the possibility of interaction with the focus. 3. The seal according to claim 1 or 2, characterized in that the forming surfaces of the hollows of the cage and rings are made parallel with the formation of an acute angle with the radius of the cylinder and the placement of the pre-pressed compression spring in the grooves. 4. The seal according to claim 1 or 2, characterized in that the spring is made in the form of a previously deformed curved rod. 5. The seal according to claim 1 or 2, characterized in that an annular groove is made on the surface of the ring mating with each ring, and annular grooves are formed in the rings corresponding to the grooves with the formation of an annular space with a twisted torsion spring placed. 6. The seal according to claim 1 or 2, characterized in that the recesses in the cage and rings are made with the simultaneous formation of a solid groove at the ends of the groove and the interaction of the side surfaces of the rings with the sealing surface.

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