JPS6323646Y2 - - Google Patents

Description

[Detailed description of the invention] Gland packing or mechanical seals are used to seal the pump shaft and the casing penetration part of pumps and the like. This prevents a portion of the liquid discharged from the pump from leaking to the outside through the casing penetration, and prevents outside air from entering the pump and impairing the performance of the pump. In other words, in the case of gland packing, by pressing the packing with a packing presser and lightly sliding the packing against the shaft, a small amount of liquid leaks from the sliding part during operation, forming a liquid film, and preventing the sliding. This removes frictional heat from the parts and ensures a sealing effect. However, if the tightening force of the packing becomes too high, frictional heat will be generated, causing the liquid film to break off, causing burnout of the packing, resulting in a loss of sealing effect and a loss of driving power due to the generation of excessive frictional torque. Moreover, if the tightening force of the packing becomes too small, the amount of liquid leakage will increase and the sealing effect will be lost. In general, the pump shaft center is subjected to considerable movement in the shaft radial direction during operation, resulting in uneven spacing between the packing and the shaft, which aggravates the above-mentioned tendency. From now on, installing the packing not only requires skill, but also requires adjustment of the packing tightening as the operating time passes, requiring a large amount of work.

Furthermore, by providing the gland packing, the casing becomes longer in the axial direction, so the installation space and weight increase, and the increase becomes more significant as the hydraulic pressure increases.

In addition, in the case of a mechanical seal, the sealing material that rotates with the shaft is positioned in the axial direction and a pressing force is applied in the axial direction.The end face of the sealing material is pressed against the ring fitted in the casing, and the contact surface is A part of the discharged liquid is injected to form a liquid film to remove frictional heat and lubricate.
The sealing effect is not affected even by minute movements of the pump axis in the radial direction during operation. Therefore, liquid leakage can be almost completely prevented, but the device becomes complicated and expensive, and the axial length and weight of the pump increase as in the case where gland packing is used. Furthermore, since the sealing material constantly repeats minute reciprocating movements in the axial direction during operation, the sealing between the shaft and the sealing material is damaged in a short period of time, resulting in the complication of having to be replaced. Adoption of such mechanical seals is ideal for use as shaft seals in chemical plants, etc., as it completely prevents liquid leakage, but its performance is excessive for use in pumps that use fresh water or seawater.

It should be noted that both gland packing and mechanical seals do not have a self-adjusting function for the sealing effect in response to changes in pump pressure, so there is a problem in that as the pressure increases, the amount of leakage inevitably increases. The present invention provides a shaft sealing device for a pump intended for fresh water or seawater that eliminates these drawbacks. That is, the present invention fixes one end of a ring-shaped sealing material with a roughly L-shaped cross section, which has a sliding surface made of elastic hard resin in a corrugated shape, around the pump shaft, and the corrugated surface of the sealing material is attached to the equipment. This is a pump sealing device that prevents liquid leakage by being crimped onto a sealing lid that is adjustable and attached to the main body.

The present invention will be explained based on FIGS. 1 to 5. 1 is the pump body, 2 is the impeller, 3 is the suction port,
4 is a discharge port, 5 is a rotating shaft, and 6 is a main part of the present invention. Reference numeral 7 denotes a sealing lid having a T-shaped cross section, and is attached so as to be removable by a presser bolt 10 via a spring washer 9 so that the convex portion I can slide onto the sealing box 8. 11 is a sleeve fixed to the rotating shaft 5, and 12 is an annular sealing material having an approximately L-shaped cross section. It is fixed with bolts 14.

Note that the sealing surface of the sealing material 12 is configured in a corrugated manner, and the convex portion 15 is formed on the sealing surface 1 of the sealing lid 7.
6, a minute gap RO is formed between the sealing surface 16 and the convex portion 15, and a minute gap 17 is provided between the tip of the sealing material 12 and the sealing surface 16 of the sealing lid 7. Note that the tip of the support plate 13 is designed to particularly contribute to the contact between the convex portion 15 of the sealing material 12 and the sealing surface 16. Therefore, sealing chamber 18
By finely adjusting the position of the sealing lid 7 using the presser bolt 10 according to the pressure of the sealing material 1
2 and the sealing surface 1 of the sealing lid 7
At this time, a small amount of liquid enters from the gap 17 at the tip of the sealing material 12 to remove the frictional heat between the sealing surface 16 and the sealing material 12. Note that 19 is an O-ring.
A two-stage seal shown in FIG. 5 is used to further ensure the sealing performed in this manner.

In this case, the sealing lid 7 used in the first-stage seal shown in FIGS. 1 to 4 has a cross-shaped cross section, and the second sealing lid 23 is moved to the protrusion 20 by a presser bolt 22 via a spring washer 21. As in the case of a one-stage seal, a sealing material 12 having an approximately L-shaped cross section is fixed to the sleeve 11 together with a support plate 13 from the same direction on the inner surface with bolts 14.
Due to its elasticity, it is pressed against the sealing surfaces 16, 16 of the sealing lids 7, 23, and the pressing force thereof is adjusted by the presser bolts 10, 22.

Further, FIG. 6 shows a case in which a shaft sealing device is provided on the pump suction side so that the sealing chamber 18 becomes under negative pressure. This occurs when the internal pressure of the sealing chamber 18 increases when the pump is started or during no-load operation, and when the internal pressure of the sealing chamber 18 becomes negative pressure during steady operation, the sealing material is narrowed from the inside and outside of the two-stage sealing lid. It is designed to be worn.

That is, the annular sealing lid 7 has a cross-shaped cross section.
The convex part A of the sealing lid 7 is slidably attached to the sealing box 8 with a presser bolt 10 via a washer 9, and the second sealing cover 23 is attached to the protrusion 20 with a presser bolt 22 via a spring washer 21. Provide movable. Next, as in the case of the primary seal, the sealing material 12 and the support plate 13 are fixed to the sealing surface 16 of the sealing lid 7 from the sealing chamber 18 side with bolts 14 so as to be crimped.
Further, the second sealing lid 23 is fixed to the sleeve 11 with the sealing material 12, the holding plate 13, and the bolts 14 so that the outer sealing surface of the second sealing lid 23 and the corrugated convex portion 15 of the sealing material 12 are in contact with each other.

With this configuration, when the pressure inside the sealing chamber 18 becomes high relative to the outside air, the sealing material 12 inside the sealing chamber 18 works, and when it becomes low, the sealing material 12 provided outside the device works, so that the sealing The effects are fully expected. The support plate 13 in the above explanation refers to the sealing surface 16 of the sealing material 12.
Although the shape along the waveform has been described, it is of course possible to press the waveform convex portion 15 of the sealing material 12 from the back side with an annular ring using an elastic body as shown in FIG. It is.

Since the present invention has such a structure, the sealing material 12 made of elastic hard resin is pressed against the sealing lids 7 and 23 by its own elasticity and the spring action of the support plate 13. During load operation, the surface pressure necessary for sealing when there is no internal pressure in the sealing chamber 18 is ensured, and as the internal pressure in the sealing chamber 18 increases during pump operation, the pressing force applied to the sealing material 12 automatically increases to ensure sealing. The effectiveness is increased and liquid leakage is kept to a minimum.

Furthermore, as the pressure in the sealing chamber 18 increases, the amount of liquid flowing in from the tip gap 17 of the sealing material 12 also increases, so the necessary lubrication can be achieved by the liquid held in the recesses of the corrugated sealing surface of the sealing material 12. frictional heat is removed.

Note that if the internal pressure of the sealing chamber 18 is high and the sealing material 12 contacts the sealing surface 16 with excessive pressure, which tends to prevent the formation of a lubricating film, the surface of the sealing surface 16 and the sealing material 12 may be in contact with each other as shown in FIG. A plurality of minute grooves 17' are provided radially along the radial direction of the gap 17 and open at the point where the outer convex portion 15 contacts.

With this configuration, the internal pressure of the sealing chamber 18 causes the convex portion 1 of the sealing material 12 on the sealing chamber 18 side to
2' works to flatten the convex portion 15 and therefore move slightly outward in the radial direction, the opening area of the groove 17' increases, and a portion of the liquid in the sealing chamber 18 is transferred to the sealing surface 16. and the seal surface 12,
A liquid film is formed on the contact area to ensure lubrication and remove frictional heat.

As described above, the present invention, which replaces the conventional sealing device using gland packing and mechanical seals, is required to have a simple structure and sufficient sealing effect. The seal between the seal material and the shaft is static and does not undergo movement, so there is no risk of damage, so adjustments and maintenance that require skill are not required.
Not only does repair work become unnecessary, the installation space for the pump is reduced, weight is reduced, and an inexpensive sealing device can be provided, among other notable effects.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing the state of use of the present invention;
Fig. 2 is a longitudinal sectional front view showing the structure of the present invention, Fig. 3 is a longitudinal sectional front view showing the sealed state of the invention, Fig. 4 is a longitudinal sectional side view taken along line AA in Fig. 2, Figs. figure,
FIGS. 7 and 8 are longitudinal sectional front views showing other embodiments. 7... Sealing lid, 5... Rotating shaft, 8... Sealing box, 9... Spring washer,
10... Holder bolt, 12... Seal material, 13...
...Support board.

Claims (1)

[Scope of utility model registration request] The sliding part of the ring-shaped sealing material 12 having a substantially L-shaped cross section is formed into a wave shape, and the convex part 15 is pressed against the sealing surface 16 of the sealing lid 7 which can be finely adjusted.
A small gap 17 is provided between the peripheral edge (tip) of the sealing material 12 and the sealing surface 16, and a sealing material supporting arm 13 is provided along the base of the sealing material 12 and the back surface of the sealing material 12.
A shaft sealing device for a rotating body, characterized in that: and are integrally fixed to a rotating shaft.