Seal for a joint or juncture – Seal between relatively movable parts – Relatively rotatable radially extending sealing face member
Reexamination Certificate
2001-10-15
2003-11-04
Knight, Anthony (Department: 3676)
Seal for a joint or juncture
Seal between relatively movable parts
Relatively rotatable radially extending sealing face member
C277S408000, C277S512000, C415S112000
Reexamination Certificate
active
06641140
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a seal mechanism used in a submersible pump and, more particularly, to a lubrication oil retaining apparatus capable of effectively cooling the sliding surface of a shaft seal device disposed within an oil chamber of the seal mechanism.
BACKGROUND ART
In a conventional submersible pump, a seal mechanism is provided between a pump casing and a motor chamber. In general, in consideration of expansion of lubrication oil stemming from heating-up of the sliding surface of a shaft seal device and heating-up of a motor during rotation, lubrication oil is charged into the oil chamber of the seal mechanism in an amount such that the lubrication oil occupies 80% the overall volume of the oil chamber and thus air-reserving space is formed at the upper portion of the oil chamber.
However, when the shaft seal device is rotated, the lubrication oil flows in a vortex toward the inner circumferential wall of the oil chamber due to centrifugal force generated by the rotation of the shaft seal device, and an air-reserving space is formed at the center portion of the oil chamber. As a result, the sliding surface of the shaft seal device to be lubricated comes into an unimmersed state, resulting in deterioration of the function for lubricating and cooling the sliding surface.
In view of the foregoing, a structure as shown in
FIGS. 7
to
9
has been proposed as a measure for maintaining lubrication at the sliding surface of the shaft seal device.
The proposed structure will be described. A cylindrical wall member
110
is disposed to surround a shaft seal device
111
. Baffle plates P for directing the flow of oil toward the center axis are disposed on the inner circumferential surface of the cylindrical wall member
110
. The lower end portion of the cylindrical wall member
110
is separated from a pump-side housing
102
a
in order to form an oil inlet
113
b
along the entire circumference of the lower edge, to thereby establish communication with an oil chamber
103
. The upper end portion of the cylindrical wall member
110
is fixed to the lower surface of a motor-side housing
101
a
. A plurality of oil outlets
113
a
are formed in the cylindrical wall member
110
at appropriate positions above a sliding surface
112
a
between an upper mating ring
105
a
and a seal ring
106
a
.
However, the results of an experiment show that when the above-described structure in which the oil inlet
113
b
for communication with the oil chamber
103
is formed by the entire circumference of the lower edge of the cylindrical wall member
110
, centrifugal force is produced in the vicinity of the oil inlet
113
b
due to rotation of the double-type shaft seal device
111
, so that lubrication oil within the cylindrical wall member
110
is forced to the outside, thereby greatly hindering the action of sucking and pushing the lubrication oil up.
Furthermore, employment of the above-described structure provides negative effects such that the lubrication oil scatters outward from the plurality of oil outlets
113
a
formed in the upper portion of the cylindrical wall member
110
, with the result that the sliding surface
112
a
between the upper mating ring
105
a
and the seal ring
106
a
is not immersed in the lubrication oil. In addition, the scattered oil tends to entrap air in an air-reserving space
115
above an oil surface
114
.
Moreover, since the amount of the lubrication oil flowing out of each oil outlet
113
a
changes depending on position, air is taken into the cylindrical wall member
110
via an oil outlet
113
a
from which a smaller amount of oil flows as compared with the remaining oil outlets
113
a
. This taken air, together with the action of the baffle plates P for directing oil toward the center axis against the above-described centrifugal force, hinders circulation of the lubrication oil within the cylindrical wall member
110
, due to its stirring action. In addition, the lubrication oil and the air are intermixed, and thus fine bubbles are generated. As a result, a mixture of the oil and air reaches the sliding surface
112
a
between the upper mating ring
105
a
and the seal ring
106
a
, resulting in a decrease in the lubricating effect. Further, the flow of the lubrication oil between the inside and outside of the cylindrical wall member
110
becomes turbulent, and this turbulent flow of the lubrication oil, together with the mixing of the lubrication oil and air, drastically reduces the efficiency in cooling the sliding surface
112
a.
Moreover, although the size and number of the oil outlets
113
a
must be matched with the rotational speed of a pump shaft
104
, in actuality, varying the size and number of the oil outlets
113
a
in accordance with variation in the rotational speed is impossible at a site where the submersible pump is used.
An object of the present invention is to provide a lubrication oil retaining apparatus for a submersible pump, which apparatus prevents lubrication oil from scattering from the center portion of the oil chamber of a seal mechanism toward the circumferential wall, and which circulates the lubrication oil smoothly to thereby effectively lubricate and cool the sliding surface of the shaft seal device, irrespective of variation in rotational speed of a pump shaft and without causing the entrapment of air into the lubrication oil.
DISCLOSURE OF THE INVENTION
The present invention provides an apparatus for retaining lubrication oil at the sliding surface of a shaft seal device disposed within an oil chamber of a submersible pump. Within the oil chamber located between a motor chamber and a pump chamber, an upper mating ring of a double-type shaft seal device is fitted into an annular groove formed on the lower surface of a motor-side housing, and a lower mating ring of the double-type shaft seal device is fitted into an annular groove formed on the upper surface of a pump-side housing. An annular holding plate for preventing rotation of the lower mating ring is fixed to the upper surface of a circumferential wall surrounding the annular groove. A cylindrical wall member is disposed to surround the double-type shaft seal device. A guide vane is fixed to the inner circumferential surface of the cylindrical wall member, the guide member having a slanted surface that inclines upward toward the rotational direction of a pump shaft. An outwardly-projecting lower edge flange is provided at the lower edge of the cylindrical wall member and fixed to the upper surface of the holding plate. A lateral hole serving as an oil inlet and establishing communication between the back side of a lower end portion of the guide vane and the oil chamber is formed in the lower portion of the cylindrical wall member. An inwardly-projecting flange is provided at the upper edge of the cylindrical wall member located above a sliding surface between the upper mating ring and a seal ring, such that the flange is in close proximity to the motor-side housing. An oil outlet is formed between the upper surface of the flange and the lower surface of a circumferential wall which surrounds the annular groove into which the upper mating ring is fitted. Preferably, the clearance between the upper surface of the flange provided at the upper edge of the cylindrical wall member and the lower surface of the circumferential wall which surrounds the annular groove into which the upper mating ring is fitted is set to fall within a range of about 0.5 mm to 3 mm; and the clearance between the inner circumferential surface of the flange provided at the upper edge of the cylindrical wall member and the outer circumferential surface of the upper seal ring is set to fall within a range of about 1 mm to 3 mm.
Preferably, a guide plate is provided at the oil inlet or the oil outlet, which is an annular clearance, in order to improve the lubrication and cooling action.
REFERENCES:
patent: 2131544 (1938-09-01), Weiland
patent: 2418194 (1947-04-01), Piccardo
patent: 3076412 (1963-02-01), Harker et al.
patent: 3136258 (1964-06-01), Bood
pate
Matsumoto Satoshi
Murai Minoru
Knight Anthony
Pickard Alison K.
Tsurumi Manufacturing Co., Ltd.
LandOfFree
Apparatus for retaining lubrication oil at sliding surface... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for retaining lubrication oil at sliding surface..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for retaining lubrication oil at sliding surface... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3158305