Title: Motor pump with expansion tank
Abstract: A pump particularly adapted for use in a closed fluid circuit, as within its housing a resiliently compressible chamber in contact with the fluid being conveyed by the pump so that any pressure change within the fluid caused by temperature variations can be volumetrically absorbed by compression or extension of the chamber.
Patent Number: 6,986,640 Issued on 01/17/2006 to Laing
| Inventors:
|
Laing; Karsten A. (La Jolla, CA)
|
| Assignee:
|
Laing; Oliver (DE);
Laing; Karsten (DE);
Laing; Birger (DE)
|
| Appl. No.:
|
152266 |
| Filed:
|
May 20, 2002 |
| Current U.S. Class: |
415/126 |
| Current Intern'l Class: |
F04D 29/40 (20060101) |
| Field of Search: |
415/126,127,128
|
References Cited [Referenced By]
U.S. Patent Documents
| 3591079 | Jul., 1971 | Peters.
| |
| RE30334 | Jul., 1980 | Coles.
| |
| 4488856 | Dec., 1984 | Preble et al.
| |
| 4658166 | Apr., 1987 | Oudet.
| |
| 4682067 | Jul., 1987 | Oudet.
| |
| 4866323 | Sep., 1989 | Oudet et al.
| |
| 5237309 | Aug., 1993 | Frantz et al.
| |
| 5797430 | Aug., 1998 | Becke et al.
| |
| 5993170 | Nov., 1999 | Stevens et al.
| |
| 6074092 | Jun., 2000 | Andrews.
| |
| Foreign Patent Documents |
| 45808 | Jun., 1887 | DE.
| |
| 78075 | May., 1893 | DE.
| |
Other References
Minimotor SA Product Design Web Page Mar. 2, 2002 Minimotro SA, Switzerland.
The New Quantum Leap in Motor Technology: "Ferrous Loss-Free".
|
Primary Examiner: Nguyen; Ninh H.
Attorney, Agent or Firm: Foley & Lardner LLP
Claims
What is claimed is:
1. A pump used for conveying fluid in a closed fluid circuit, said pump comprising:
a housing having a plurality of walls, at least one inlet and at least one separate
outlet; and
a resiliently compressible chamber within said housing, and in contact with said
closed fluid circuit, said compressible chamber having a flexible membrane portion,
said flexible membrane portion forming a boundary between said compressible chamber
and said closed fluid circuit;
wherein any expansion of said fluid is compensated by a corresponding volumetric
compression of said compressible chamber, and
wherein said compressible chamber is enclosed so as to be not accessible to said
fluid.
2. The pump of claim 1, further comprising: means for resiliently biasing said
flexible membrane portion toward a full extension position.
3. The pump of claim 2, wherein
the means for resiliently biasing includes a spring element, and
wherein the full extension position is based solely on material characteristics
of the spring element and the flexible membrane portion.
4. A pump used for conveying fluid in a closed fluid circuit, said pump comprising:
a housing having a plurality of walls; and
a resiliently compressible chamber within said housing and in contact with said
fluid circuit;
whereby any expansion of said fluid is compensated by a corresponding volumetric
compression of said chamber;
wherein said chamber comprises a flexible membrane portion and means for resiliently
biasing said membrane portion toward the full extension; and
wherein said chamber is not accessible to said fluid and communicates with ambient
air through an aperture in said housing.
5. The pump of claim 4, wherein
said chamber further comprises a rigid section;
said membrane extends between said rigid number and a portion of one of said
walls; and
said means for resiliently biasing comprise a coil spring compressibly held between
said rigid member and said portion.
6. The pump of claim 5, which further comprises means for indicating a degree
of expansion of said chamber.
7. The pump of claim 6, wherein said means for indicating comprises a plunger
within said chamber, said plunger being secured to said rigid member and having
a tip protruding outside said housing through a hole in said portion.
8. A pump used for conveying fluid in a closed fluid circuit, said pump comprising:
a housing having a plurality of walls; and
a resiliently compressible chamber within said housing said in contact with said
fluid circuit;
whereby any expansion of said fluid is compensated by a corresponding volumetric
compression of said chamber;
wherein said chamber comprises a flexible membrane portion and means for resiliently
biasing said membrane portion toward the full extension;
an impeller axially perpendicular to a portion of one of said walls;
said portion having an inlet substantially coaxial with said impeller; and
wherein said chamber has an annular shape substantially coaxial with said fluid
inlet and impeller.
9. The pump of claim 8, wherein said chamber surrounds a portion of said impeller.
10. The pump of claim 8, wherein said chamber has an outer peripheral portion
formed by a section of one of said walls.
11. The pump of claim 8, wherein said means for resiliently biasing comprises
a coil spring positioned in said chamber axially with said impeller.
Description
FIELD OF THE INVENTION
This invention relates to pumps and more particularly to pumps used as part
of a closed fluid circuit.
BACKGROUND OF THE INVENTION
When a fluid is circulated through a closed circuit by means of a pump, it is
often necessary to provide a structure or mechanism to accommodate expansion or
contraction of the conveyed fluid due to change in temperature which are sufficient
to affect the volume of the fluid itself or the capacity of certain components
in the circuit.
SUMMARY OF THE INVENTION
The principal and secondary objects of this invention are to provide a convenient
mechanism within a pump to accommodate volumetric variation in the conveyed fluid
or other components of a closed fluid circuit and avoid the necessity of providing
a structure or mechanism along the fluid circuit to compensate for those variations
often caused by change in ambient or internal temperature.
These and other objects are achieve by providing within the housing of the
pump, a resiliently compressible chamber formed in part by a flexible membrane,
which chamber is in contact with, but not accessible to the fluid being conveyed
by the pump.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a first embodiment of a pump with resiliently compressible internal
chamber according to the invention;
FIG. 2 is a cross-sectional view of a second embodiment of a similar pump; and
FIG. 3 is a cross-sectional view of a third embodiment of the pump.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
Referring now to the drawing, there is shown in FIG. 1, a spherical pump
1 in which the impeller
2 is secured to the top surface of a hemispherical
rotor
3 preferably comprising a permanent magnet. Fluid entering the pump
through the inlet
4 is centrifugally directed toward an outlet
5.
An annular stator
6 comprising a soft magnetic yoke
7 and a winding
8 applied to the inner surface of the yoke is separated from the fluid by
a watertight septum
9 having a annular portion
10 extending into
the air gap
11 between the rotor and the stator. The rotor is immersed in
the fluid and supported by a single-ball bearing mounted at the end of a shaft
13 projecting from a medium flat section
14 of the septum, and into
an axial cavity
15 in the lower portion of the rotor.
A resiliently compressible chamber
16 is positioned against the inside
surface
of the top wall
17 of the pump enclosure. The chamber comprises a rigid
member
18 substantially parallel to the top wall
17 and a circular
flexible membrane
19 extending between the periphery of the rigid member
18 and the inside surface of the top wall
17 to form a chamber which
is in contact with a fluid-holding area
20 of the pump housing but whose
inside
21 is not accessible to the conveyed fluid. An aperture
22
in the inside portion of the wall
17 puts the interior of the chamber in
communication with ambient air outside the pump. A series of coil springs
23,
24 are compressed between the rigid member
18 and the top wall
17
of the pump enclosure.
A plunger
25 inside the chamber has a first end connected to the rigid
member
18 and an opposite end having a tip protruding through a window
28
in the top wall of the pump enclosure; whereby the position of the tip
27
provides an approximate indication of the degree of compression or expansion of
the chamber.
In the second embodiment of the invention
31 illustrated in FIG. 2, an
annular compressible chamber
32 is formed by a pulley-shaped membrane
33
having both rims
34,
35 secured to the inside surface of a lateral
wall
36 of the pump housing. A coil spring is coaxially positioned inside
the annular chamber
32. In this particular embodiment, the pump inlet is
conveniently positioned coaxially and above the impeller and the propeller is positioned
proximal, and axially perpendicularly to the top wall
40 of the enclosure.
This second embodiment of the invention allows for a more compact pump housing
since a top portion
41 of the impeller is surrounded by the resiliently
compressible chamber
32 rather than being located below it as described
in connection with the first embodiment of the invention.
In the third embodiment of the invention illustrated in FIG. 3, a simple barometric
bellow
42 is used in a pump similar to the one illustrated in FIG. 1 in
lieu of the resiliently compressible chamber
16. Such a bellow is commonly
found in some types of barometric instruments.
While the preferred embodiments of the invention have been described, modifications
can be made and other embodiments may be devised without departing from the spirit
of the invention and the scope of the appended claims.
*
