Note: Descriptions are shown in the official language in which they were submitted.
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HYDROSTATIC SEAL
BACKGROUND
In large pump installations there are problems
with the chamber flooding, especially where the head water
level is higher than the sump floor level. In this type
of an installation there is a problem in keeping water
from getting into the subfoundation because of inadequate
sealing. There are also problems in installing seals to
prevent them from getting torn and damaged during the
installation procedure. Prior seals tore durin~ assembly
because of the high stresses encountered at the flange
joints. In order to avoid these problems, the easiest way
would be to make a seal in a single piece but this is not
practical because of the configurations of the various
pumps presenting elbows which are angular and have larger
dimensions than the axial opening in the seal. Thus, if a
one-piece seal was provided it would have to stretch for
mounting purposes over the structure of the pump and this
stretching would deform the seal where it would be
inoperable to function for sealing purposes. It has also
been found that a single-piece,no-seam-seal was not
practical for assembling`in the shop on the pump prior to
shipment. This is true because when shipping these large
pumps, they cannot be containerized so that it is out in
the open and the seal, likewise, if assembled to the pump
during assembly in the shop, would also be out in the open
and thus subject to damage which has been a very high
risk. The only practical way to ship seals is to ship
them independently of the pump in a crate by themselves.
SUMMARY OF THE INVENTION
In accordance with the preferred embodiment of
the present invention, there i5 provided a hydrostatic
seal which includes a plurality of layers of circular
confirguration, each layer being constructed of sectors
and the sectors of each layer overlaping the lower layer.
The hydrostatic seal of the present invention in its
preferred form is constructed from a total of thirty-two
45 curved segments manufactured from natural rubber
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reinforced with fiberglass. The 45 segment construction
is considerably less expensive to manufacture due mainly
to the smaller die that can be used and the greater
flexibility with tolerances that is associated with the
smaller die. Unlike prior rubber diaphragms which were
torn during field assembly, the natural rubber fiberglass
reinforced seal of the present invention improves the
ability of the seal ring to withstand the abuse that is
inherent in field assembly.
Using a natural rubber cement, the 45 segments
are glued together in a staggered arrangement, until a
completely circular ring is formed. This construction is
done in assembly in the manufacturing shop wherein each
layer is layed out in a circular ray and the next layer of
segments is arranged in staggered relation to the lower
layer and the two layers glued together. This arrangement
is continued for a four-layer thickness ring. For field
assembly purposes, one staggered section is not glued
until the entire ring is assembled in the field. This
allows the seal to be eased into position around the pump
assembly and lowered into its assembled position and
thereafter the unglued staggered section may be glued
together to form a complete hydrostatic no-leak seal.
DESCRIPTION OF THE DRAWINGS
Fig. 1 is a view in vertical elevation and
partly in section showing the pump installation with the
pump mounted in a sump section and showing the hydrostatic
seal of the present invention in sealing position;
Fig. 2 is a enlarged fragmentary view showing
the relationship of the hydrostatic seal with relationship
to the pump and to the foundation;
Fig. 3 is a plan view of the assembly of the
sectionalized segments of the hydrostatic seal;
Fig. 4 is the view in vertical section taken in
the plane represented by the line IV-IV in Fig. 3, showing
the layers separated t~ illustrate the separation that is
left between two segments in each layer; and
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Fig. 5 is a plan view of a single segment of the
complete hydrostatic seal shown in Fig. 3.
DESCRIPTION O~ T~IE I~VENTION
As shown in Fig. 1, a vertical column water pump
10 is mounted and secured to the concrete foundation 11 at
the pump support plate 61. The pump 10 consists of the
motor and motor pedestal 21 which is bolted to the pump
support plate 61, an upper pipe column 23, a discharge
elbow 60 from which the water exits down a discharge pipe
17, the lower casing section 28, and the pump rotating
element consisting of the impeller 29 and the line shaft
33.
The construction of the support structure 12 is
such that the water level 16 in the pump intake basin 14
is at an elevation above the lower pump access room floor
36. The lower pump access room 20 is sealed against the
high water level 16 by sealing the circular floor opening
27 with the hydrostatic seal 40 of the present invention.
The hydrostatic seal 40 is constructed so as to
be flexible as possible while exhibiting excellent sealing
characteristics such as to equal one-piece construction.
The seal 40, while providing the above characteristics,
also is arranged so as to present a configuration of a
single turn or spiral screw thread for assembly around the
pump without damage to the seal.
The seal 40 is constructed of a plurality of
curved segments, which, for the seal shown, comprises
thirty-two 45 curved segments 41. The segments are
identical and each is manufactured from natural rubber
that is reinforced with fiberglass. The construction of
the seal of 45 curved segments is considerably less
expensive to manufacture than a two-piece or solid
one-piece member. This is true because the die, which
must be acurately constructed to close tolerances to form
the segments is considerably less expensive to manufacture
than a much larger die necessary for two-piece or
single-piece construction.
Eight 45 curved segments, having a thickness of
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1/16 of an inch, are arranged in circular array, and glued
in abutting relationship to form a single circular layer
46. The joint 51 at one position is left unglued so as to
provide easy separation.
As previously mentioned the seal 40 is
constructed of four concentric layers with each layer
comprised of eight 45~ curved segments 41. As shown in
Fig. 4, the layers are identified as 46, 47, 4~ and 49.
As indicated in Fig. 4 one joint between two adjacent
segments is left unbonded as indicated at 51, 52, 53 and
54 in each layer. Also the segments in adjacent layers
are staggered relative to each other. The preferred
staggered arrangement is a 1/3 relationship, as shown in
Fig. 4. As shown, the segment 41A associated with the
lower layer 46 has a 1/3 end surface 56 which is
overlapped by the segment 41I associated with the adjacent
layer 47. In like manner the segment 41H associated with
the ring layer 46, which will normally be in a position
adjacent to the segment 41A and in abutting relationship,
is arranged so as to leave 1/3 of the adjacent layer
segment 41J bottom surface exposed. The same relationship
obtains for the ends 52 of segment 41I associated with
ring layer 47 and segment 41R of ring layer 48. The 1/3
staggered relationship is also maintained between adjacent
segments associated with the ring layers 48 and 49. Thus,
the separation provided permits the hydrostatic seal to be
installed around the pump in the field without damaging or
stretching the seal as would be the case if the seal was a
complete ring. This is true because the elbow portion 60
of the elbow housing 24 extends a substantial distance
outwardly from the vertical casing surface.
Installation of the seal is more readily
understood from the following explanation. The pump is
precision aligned and mounted on the main pump support
plate 61 as shown in Fig. 1. After the pump is bolted and
secured to the main plate, the sub-floor curb ring 62 is
aligned and leveled in relation to the hydrostatic seal
` mounting flange 63 on the pump. As shown in Fig. 2 the
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curb ring 62 is then secured into place with grout and
anchor bolts 64. This curb ring, and the hydrostatic seal
mounting flange on the pump, provide the outer and inner
supports, respectively, for the hydrostatic seal ring 40.
5 As shown in Fig. 3, the seal 40 is manufactured with
precisely located stud-receiviny openings 66 and 67 which
are arranged in concentric circles. The inner circle of
stud opening 66 receives the pump flange studs 68 and the
outer stud openings 67 being adapted to receive the curb
10 ring studs 69. After the mounting studs 69 are screwed
into the curb ring 62, the plurality of mounting studs 68
are also screwed into the pump flange 63 and, the
hydrostatic seal ring 40 is placed over the studs. At the
sealable step joint, as shown in Fig. 4, the hydrostatic
15 seal ring is lifted off of the studs, one of the two
sealing templates 21 (not shown) is placed over the studs,
and the lower half of the sealable step joint is laid over
this template (not shown). Natural rubber cement is
spread over the bottom section or layer and under the top
20 section of the sealable joint, the top section is laid
over the studs and matched with the bottom section, and a
second seal template (not shown) is placed over the top
section to make a "sandwich". Nuts 71 and 72 are screwed
onto the studs associated with the outer ring or curb stud
25 69 and also the studs 68 associated with the inner ring or
flange and tightened to compress the seal templates and
joint. After the joint is set and dry, the assembled
sandwich of bottom template (not shown), hydrostatic seal
40, and upper template (not shown), is lifted and the
30 sealing templates are removed. Final assembly of the seal
group is made by placing outer and inner segmented hold
down rings 76 and 77 over the hydrostatic seal ring and
tightening the nuts 71 and 72 on each stud 68 and 69 of
the respective circles. Thus, the seal ring is now one
35 complete ring without any joint. In the previous known
seals, the joint or joints were difficult to seal. There
were high stresses in the immediate vicinity of the seam
and there was leakage at the seam after a period of time.
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~ith the present seal, the joint is easily sealed and,
after it is dry, is identical to any other section of the
ring. This ensures that stresses are equally distributed
over the entire ring, versus concentrated at one section,
and the possibility of leakage at any one section is
diminished.
The unique single joint design reduces the amount of time,
labor and expertise required for initial seal installation
as well as future replacement of the hydrostatic seal
ringO This ensures that a high degree of pump
serviceability is maintained.
