JPH0137261Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a floating ring seal for the purpose of sealing a rotating shaft, and is widely used as a shaft sealing device for high-speed, high-pressure rotating machines.

(Prior art) Generally, floating ring seals are widely used as shaft seals for high-speed, high-pressure rotating machinery.
The leakage flow rate of the fluid is restricted by making the gap formed between the inner circumferential surface of the floating ring and the outer circumferential surface of the shaft extremely small and increasing the flow resistance of the fluid passing through the gap.

FIG. 3 is a sectional view of a conventional floating ring seal, in which a floating ring seal 12 is fitted to the main shaft 11 with a slight gap, and although not shown, there are A suitable rotation stopper such as a pin is provided. Also, one end surface (the left end surface in the figure) 16 is in contact with the inner surface of the casing 13, and the end surface 16
and the sliding surface 17 with the outer circumferential surface of the rotating shaft 11, respectively, sealing the fluid.

During the rotation of the shaft 11, arrows 14 and 1 appear from the sliding surface 17.
The sealing fluid leaks in the direction shown in 5, and the leakage flow rate is determined by the size of the gap between the sliding surfaces 17, the pressure difference, etc.

(Problem to be solved by the invention) In the conventional floating ring seal described above, the smaller the gap between the sliding surface and the rotating shaft, the smaller the leakage flow rate, but on the other hand, the rotation of the shaft The viscous friction loss increases, and the removal of heat generated by leakage flow becomes insufficient, resulting in a shortened life. Therefore, there is naturally a limit to the setting of the gap and the restriction of the leakage flow rate. Further, when the sealing pressure changes significantly, if the leakage flow rate at high pressure is reduced, the leakage flow rate at low pressure becomes extremely small, which causes seizure of the sliding surface.

(Means for Solving the Problems) In order to solve the above-mentioned problems of the prior art, the present invention provides cooling fins on the outer periphery of the floating ring seal and directs a portion of the sealing fluid through the fins. It is characterized by forming a passage for circulation through which the floating ring seal is forcibly cooled.

(Function) The present invention is configured as described above, so that
The rotating floating ring seal is
The end face on the outflow side of the sealing fluid seals the fluid with the inner surface of the casing, and the inner circumferential surface (sliding surface) of the ring seals the fluid with the outer circumferential surface of the rotating shaft, but there is a slight gap between the inner circumferential surface of the ring and the outer circumferential surface of the shaft. Since the sealing fluid is provided, leakage of the sealing fluid occurs. However, by reducing the size of the gap in the sliding surface, the flow resistance of the fluid passing through the gap is increased, and the leakage flow rate of the fluid is limited.

As described above, a part of the sealing fluid is constantly circulated through the fins during rotation of the shaft, so the floating ring seal is forcibly cooled and the sliding contact with the shaft is The heat generated on the moving surface is efficiently removed.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a main part of a floating ring seal showing an embodiment of the present invention, and FIG. 2 is a front view of the floating ring, with reference numeral 2 in the figure.
Reference numerals 1 to 27 indicate parts equivalent to numbers 11 to 17 in FIG. 3, respectively. That is, the floating ring 22 which is provided with a rotation stopper (not shown) has one end surface 26.
The inner surface of the casing 23 is sealed with the inner surface of the casing 23, and the outer circumferential surface of the rotating shaft 21 is sealed with the sliding surface 27, and the leakage flow of the sealing fluid flows in the directions of arrows 24 and 25, which is the same as the conventional one (Fig. 3). .

In this embodiment, a plurality of radial cooling fins 28 are provided on the outer circumference of the floating ring 22.
A circulation channel 3 leading to a seal chamber 22a containing a
0 is formed between the sealing fluid inflow side chamber 31 and the sealing fluid inflow side chamber 31 .

With the above configuration, while the shaft 21 is rotating, the sealing fluid in the sealing chamber 22a passes through each cooling fin 28 and removes the heat generated on the sliding surface 27, and then passes through each cooling fin 28. The liquid is discharged through an annular chamber 30a formed on the outside, through the circulation channel 30. The circulating flow discharged through the flow path 30 is returned to the low-pressure suction side in the case of a pump, for example, and in some cases, it is cooled by a forced circulation device equipped with a cooling device and returned to the sealing chamber. be returned.

According to this embodiment, when the above-mentioned circulating flow passes through the fins 28, the floating ring is forcibly cooled, so that the heat generated on the sliding surface 27, which has a small gap, is efficiently dissipated. will be removed. Therefore, since the gap between the sliding surfaces can be made small, the leakage flow rate can be reduced, and seizing does not occur on the sliding surfaces, allowing for long life and use over a wide pressure operating range.

In the above embodiment, the design of the cooling fins such as the shape and number of cooling fins can be changed as appropriate, and the location of the circulation passage, the shape of the passage, and forced circulation such as a pump in the middle of the passage can be changed. It goes without saying that various designs are possible, including the provision of cooling means such as means and fins.

(Effects of the invention) As explained above, according to the invention, cooling fins are provided on the outer periphery of the floating ring seal, and a part of the sealing fluid is circulated through the fins. Since the floating ring seal is forcibly cooled, there is no need to remove the heat generated by sliding due to leakage flow as in the past, and therefore the leakage flow rate can be extremely small, resulting in a long life and a long operating range. A wide floating seal can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a floating ring seal showing an embodiment of the present invention, Fig. 2 is a front view of the floating ring in Fig. 1, and Fig. 3 is a sectional view of a conventional floating ring seal. . 21... Rotating shaft, 22... Floating ring, 26... End face, 27... Sliding surface, 28... Cooling fin, 30... Circulation passage.

Claims (1)

[Claims for Utility Model Registration] 1. In a floating ring seal for the purpose of sealing a rotating shaft, a cooling fin is provided on the outer periphery of the floating ring seal, and a part of the sealing fluid is passed through the fin. A floating ring seal characterized by having a circulation channel. 2. The floating ring seal according to claim 1, wherein the circulation flow path is formed between the outer casing of the fin and the sealing fluid inlet chamber.