Fluid pump

A fluid pump having a pump housing, and an impeller in the housing and coupled to the drive shaft of a drive motor. An improved main seal is provided in the housing to seal the hole through which the drive shaft extends. The seal includes a carbon seal member having a flat end face in sliding relationship to the flat end face of a ceramic seal rotatable with the drive shaft and the impeller. The seal further includes a pre-loaded element which forces the two seal faces together. An improved mounting bracket is provided to mount the drive motor and the pump housing on a fixed support. The mounting bracket includes a central mounting plate and a pair of inclined, side wings which extend from the pump housing toward the drive motor so as to eliminate the need for a second bracket on the opposite side of the motor.

This invention relates to improvements in the construction of water pumps 
typically of the type used for a swimming pool and, more particularly, to 
a fluid pump having an improved seal and mounting bracket. 
BACKGROUND OF THE INVENTION 
Fluid pumps of conventional design typically have seal and mounting 
problems associated with them so that improvements are always being sought 
to minimize such problems, if possible. For instance, one type of fluid 
pump made by Coleco Corporation has a seal which requires a supplementary 
lubricant to insure seal life. Moreover, to meet requirements of 
Underwriters Laboratories requiring double insulation, the motor shaft has 
to be separated with an air gap of approximately 1/8 of an inch. This is 
accomplished by separating the shafts by interconnecting two spaced shaft 
segments with a water slinger. The problem with this design is as follows: 
1. There is excessive run-out of the two motor shaft segments and the water 
slinger interconnecting the shaft segments. This condition causes the 
shaft coupled to the impeller to run in an orbital path, causing seal 
problems to be created due to seal oscillation, premature work hardening 
of seal material and seal lip skipping. 
2. The water slinger is costly to manufacture due to Underwriter Laboratory 
requirements and close tolerances on dimensions. 
3. The seal requires a special lubricant to allow for durability without 
burnout. 
4. The shaft segment coupled to the impeller requires high quality surface 
finish and surface preparation to allow the seal to function properly. 
5. In addition to the foregoing, the cost of the components is relatively 
high. 
In another prior art fluid pump, such as one of the type made by Doughboy 
Corporation, the motor drive shaft coupled to the impeller is of a 
one-piece construction and the base seal requires an outer metallic can 
for housing a rubber seal and forming a stop for a pressure spring. A 
carbon ring mates to a ceramic seal ring to seal the pump cavity. 
The problems associated with this last-mentioned prior art fluid pump are 
that the metallic seal can is in direct contact with the pool water so 
that the rear motor pump mounting bracket has to be of an insulating 
material, such as plastic, to meet Underwriter Laboratory requirements. 
Moreover, the seal pressure spring is sensitive to spring rate (pressure) 
because of low motor starting torques. This condition requires very close 
assembly tolerances which are costly. Other problems include the high cost 
of seal assembly and the fact that the motor pump mounting base requires 
low tolerance manufacturing techniques. 
Because of the foregoing drawbacks in prior art fluid pumps, a need exists 
for improvements in a fluid pump in which a motor drive shaft is coupled 
to an impeller through a seal for isolating a pump cavity containing the 
impeller. The present invention satisfies this need. 
SUMMARY OF THE INVENTION 
The present invention is directed to an improved fluid pump with a seal 
defined by a seal body secured in a position across the shaft receiving 
opening of a cavity. A ceramic seal rotatable with the impeller rotates 
along the end face of a stationary carbon seal carried by an annular seat 
on a conical extension of the main seal with the conical extension being 
pre-loaded and under compression so as to urge the mating faces of the 
carbon seal and the ceramic seal together at all times, whereby the 
ceramic seal can rotate relative to the carbon seal while maintaining a 
sealed junction therebetween. 
The ceramic seal is surrounded partially by a shell forming one end part of 
a resilient boot whose opposite end part provides a water slinger which 
surrounds the drive shaft of the motor. Thus, the ceramic seal is 
positively coupled to the impeller for rotation therewith. 
The outer periphery of the seal body is clamped between the outer 
peripheral flange of a pump housing and an end plate forming a part of the 
mounting bracket of the present invention. The mounting bracket includes 
an end flange on the end margin of the mounting plate. A pair of flared 
side support wings are angled away from the motor center line and extend 
rearwardly towards the rear of the motor. The outer ends of the mounting 
plate and the wings are coupled by fasteners to the mounting support fixed 
relative to the motor. In this way, the bracket of the present invention 
eliminates one of the two brackets of the prior art and provides mounting 
supports for the rear of the assembly of the fluid pump while improving 
fan and electrical clearance, eliminating the need to assemble rear 
bracket mounting screws between fan blades, providing a mounting 
configuration that allows old design interchangeability, allowing for 
shorter pump/motor assembly lengths, and eliminating magnetic field 
shrouding. 
The primary object of the present invention is to provide an improved fluid 
pump which eliminates certain problems associated with the seals and 
brackets of conventional fluid pumps and provides an efficient main seal 
as well as simplifying the mounting requirements for the pump. 
Other objects of this invention will become apparent as the following 
specification progresses, reference being had to the accompanying drawings 
for an illustration of the invention.

The fluid pump which is the subject of the present invention is broadly 
denoted by the numeral 10 and includes a pump housing 12 provided with an 
interior space 14 for rotatably receiving a rotary impeller 16 mounted on 
a shaft 18 of a drive motor 20. Shaft 18 extends through the motor and has 
a fan blade 22 thereon for cooling the motor during use. 
Pump housing 12 has a tubular extension 24 defining a fluid inlet 26 for 
water, for instance, if the pump 10 is used with a swimming pool or the 
like. A second extension 28 on the cylindrical main portion 30 of pump 
housing 12 defines a fluid outlet 32 which is substantially tangential to 
the rotary path of travel of impeller 16. 
Pump housing 10 has an annular flange 34 surrounding one end thereof. 
Screws 36 passing through flange 34 are threaded into end plate 38 of a 
mounting bracket 37 so that the end plate 38 closes the opening at the one 
end of the pump housing except for a central hole 39 in end plate 38 to 
allow shaft 18 to extend into the space 14. The inner end of shaft 18 is 
threadably or otherwise rigidly secured to impeller 16 so that the 
impeller will rotate with the shaft when motor 20 is energized. 
A seal 40 is provided within space 14 adjacent to end plate 38 for sealing 
the central hole 39 in the end plate. To this end, the seal includes a 
disk-like body 42 which is contiguous with the inner surface of end plate 
38 and held and has an outer peripheral margin 44 which is clamped between 
flange 34 and plate 38 by screws 36 as shown in FIG. 3. Seal body 42 has 
an annular enlargement 46 on an annular end segment 51 extending laterally 
from one end of a tubular element or part 50 as shown in FIG. 3a. 
Enlargement 46 is complementally received within an annular recess formed 
by an annular, outwardly bowed portion 48 of end plate 38 as shown in FIG. 
3a. End segment 51 is integral with part 50 as shown in FIG. 3a. 
Seal body 42 further includes tubular, cone-shaped central element or part 
50 (FIG. 3a) having and annular, transversely U-shaped end element or seat 
52 at the opposite end of part 50 for receiving an annular rib 54 of a 
carbon ring seal 56 having an end face 58 in sliding engagement with the 
end face 60 of a ceramic ring seal 62 which is captured by an annular 
shell 64 forming a part of a tubular boot 65 which is fitted over and 
rotates with shaft 18. A disk-like end member 70 is integral with boot 65 
on the opposite end thereof and serves as a water slinger. Shell 64 is in 
frictional engagement with the inner end face of impeller 16 so that shell 
64 and ceramic seal 62 rotate with the shaft 18 relative to carbon seal 
56. 
The conical shape of part 50 is selected so that the seal can be and is 
pre-loaded by tension at the junction of the side wall of part 50 and the 
end segment 51. When pre-loaded the part 50 is under compression and the 
junction between the side wall of part 50 and end segment 51 is under 
tension so that the side wall of part 50 is biased to the left when 
viewing FIG. 3a, to thereby bias end face 58 into engagement with face 60 
so that the mating faces will remain in contact with each other as face 60 
rotates relative to face 58 under the influence of shaft 18. 
Seal body 42 can be optionally provided with means defining a curved or 
annular space or cavity 72 (FIG. 3). The purpose of cavity 72 is to reduce 
the volume of space 14. FIG. 7 shows that, if used, the cavity can be 
annular. 
Seal 40 is, therefore a combination of the face seal caused by surfaces 58 
and 60 being in contact with each other (FIG. 3a) and the outer peripheral 
seal provided at the outer peripheral portion 44 (FIG. 3) of the seal body 
42. The seal of the present invention is unique because it does not 
require a seal can, spring, separate rubber boot or seal retainer as in 
certain prior art devices, on of which will be disclosed hereinafter. Seal 
40 is of a one-piece construction and of molded rubber or other flexible 
material with a carbon face seal ring 56 nested in molded seat 52 which 
positions and seals the carbon ring 56. 
The water seal between carbon and ceramic seals 56 and 62 is maintained by 
elastic energy that is created when the main seal 40 is pre-loaded during 
the ceramic seal assembly. FIG. 3a shows the position of conical part 50 
before and after pre-loading the seal body. Pre-loading the seal 
eliminates the necessity to use wire springs, seal retainers and seal 
cans. The seal pre-load force can be varied by increasing or 
decreasing the material durometer or by changing the preset dimensions of 
component parts. 
The seal 40 has at least five functions and advantages, namely it seals the 
outer housing cavity 14, it provides a means to retain the carbon seal 56 
concentric with ceramic seal 62, it provides the means to keep carbon seal 
56 from rotating as shaft 18 is rotating, it can for a pump cavity 
displacement reducing volume 72 which reduces water circulation in the 
pump, and provides an insulation barrier between pump water and electrical 
components such as metallic mounting brackets and the metallic drive shaft 
18 of the motor. The ceramic seal 62 is sealed by boot 65 and the boot 
further provides an electrical insulator to encapsulate motor shaft 18 and 
provide water slinger 70, all as a one-piece component. 
Bracket 37 is typically of a plastic material and is of one-piece 
construction. It includes a first end flange 80 on plate 38 and a pair of 
inclined side wings 82 integral with plate 38 as shown in FIGS. 4-6. The 
bracket is therefore unitized and the two support wings 82 are angled away 
from the motor center line and back towards the rear of the motor. Bracket 
37 provides motor mounting support in the rear; it eliminates the need for 
a second bracket; it improves fan and electrical isolation; it eliminates 
the need to assemble rear bracket mounting screws between fan blades; it 
provides a mounting configuration that allows old design 
interchangeability; it allows for shorter pump/motor assembly lengths; and 
it allows, by virtue of wings 82, to eliminate magnetic field shrouding. 
The present invention is to be contrasted with the pump structure of 
several prior art pumps shown in FIGS. 1 and 2. In the pump of FIG. 1, a 
pump housing 90 has an impeller 92 mounted on a shaft 94 extending through 
a mounting plate 96 having a central hole 98 which is covered by a seal 
100. An insulator-slinger member 102 connects shaft 94 up with the drive 
shaft 104 of a drive motor 106 having a cooling fan 108 on the opposite 
end of shaft 104. To meet Underwriters Laboratories requirements of double 
insulation, the prior art motor 88 shown in FIG. 1 must have shaft 104 
separated from shaft 94 with a 150 -inch air gap provided by water slinger 
102. The problems associated with this design are as follows: 
1. There is excessive run-out of the motor drive shaft 104, slinger 8 and 
shaft 94. This condition causes shaft 94 to run in an orbital path which 
creates seal life problems due to seal oscillation, premature work 
hardening of seal material and seal lip skipping. 
2. Water slinger 102 is costly and difficult to manufacture due to 
requirements of Underwriter Laboratories and close tolerances on 
dimensions. 
3. Seal 100 requires a special lubricant in the central cavity 101 to allow 
endurance without burn-out. 
4. Shaft 94 requires high quality surface finish and special microseal 
surface preparation to allow the seal to function on the shaft. 
5. The cost of the components of the water pump 88 are excessive. 
The prior art water pump 88 also requires a pair of spaced brackets 107 and 
109 to support the weight of motor 106. The problems with concept include 
the following: 
1. The cost of two brackets as distinguished from the cost of a single 
bracket. 
2. The difficulty in the assembly of the bracket. 
3. The problems of obtaining sufficient motor terminal and coil dielectric 
air clearance due to motor bracket location and requirements. 
4. The cooling fan problem, the close fit requirements, the fan shrouding 
and the inefficiency due to space limitations. Another prior art water 
pump is broadly denoted by the numeral 120 and is of the type made by 
Doughboy Corporation. It has a pump housing 122, an impeller 124, a drive 
shaft 126, a drive motor 128 with a cooling fan blade 130. A mounting 
bracket 132 mounts pump housing 122 in a position so that the impeller 124 
can be coupled to drive shaft 126. An O-ring 134 is provided at the end 
face of pump housing 122 for engagement with the adjacent face of bracket 
122. Shaft 126 is a one-piece design which threads into impeller 124. The 
base seal 136 is of conventional design and requires a outer metal can 
138, a conical rubber seal 140, a pressure spring 142 and a carbon face 
ring 144 which mates to a ceramic seal ring 146 to seal the pump cavity. 
Because of the metal seal base 138, the metal seal is in direct contact 
with the pool water entering the pump through the inlet 145 thereof. 
Because of this, the rear motor/pump mounting bracket 132 must be of 
plastic material to meet Underwriter Laboratory requirements. 
The seal pressure spring 142 is sensitive to spring rate (pressure) because 
of low motor starting torque. The requires very close assembly tolerances 
which are costly. Another problem is the high cost of the assembly of the 
seal of water pump 120. The motor pump mounting base requires low 
tolerance manufacturing techniques. 
The present invention avoids the problems associated with the prior art 
devices shown in FIGS. 1 and 2. It provides a combination face and pump 
seal. It further provides a ceramic seal boot/slinger. Finally, it 
provides a unitized motor mounting bracket.