Pumps – Motor driven – Fluid motor
Reexamination Certificate
2000-09-25
2002-08-20
Freay, Charles G. (Department: 3746)
Pumps
Motor driven
Fluid motor
Reexamination Certificate
active
06435844
ABSTRACT:
BACKGROUND OF THE INVENTION
a) Field of the Invention:
The present invention relates to a pump which is used in a hot water supply apparatus or the like for feeding hot water.
b) Description of the Prior Art
An impeller pump is conventionally used as a pump in a hot water supply apparatus such as a jar, a pot or the like for feeding a liquid at a relatively high temperature.
This impeller pump has such a configuration as that shown in
FIG. 1
, and when the pump is to be used for feeding hot water, a hole
30
a
is formed in a bottom of a vessel
30
of a hot water supply apparatus to be filled with hot water and a suction port of the pump is connected to the hole. In
FIG. 1
which illustrates the configuration of the impeller pump, a reference numeral
31
represents a casing of the pump, a reference numeral
32
designates a partition panel which airtightly partitions a pump chamber
33
from a driving section
34
, a reference numeral
35
denotes a shaft which is supported by a supporting member
36
, a reference numeral
37
represents a holding member for holding an impeller and a magnet which are disposed rotatably around the shaft
35
, a reference numeral
38
designates an impeller which rotates together with the holding member
37
, and a reference numeral
39
denotes a follower magnet which rotates together with the holding member
37
: all of these members being disposed in the pump chamber
33
. In the driving section
34
partitioned with the partition panel
32
, a driving magnet
40
which is rotated with a motor
41
is disposed so as to oppose to the follower magnet
39
with the partition panel
32
interposed.
This impeller motor rotates the driving magnet
40
by driving the motor
41
and rotates a follower magnet
39
which is magnetically coupled with the driving magnet
40
by rotating the driving magnet
40
. When the follower magnet
39
is rotated, the impeller
38
is rotated to perform a pump function.
By the pump function of the impeller
38
, hot water is sucked out of the vessel
30
, sucked through a suction port
42
of the impeller pump and discharged from a discharge port
43
.
Furthermore, a diaphragm pump is known as a pump which supplies a liquid or the like.
The diaphragm pump has a configuration shown in
FIG. 2
, wherein a reference numeral
50
represents a motor, a reference numeral
51
designates a crank body which is fixed to an output shaft
50
a
of the motor
50
, a reference numeral
52
designates a driving shaft which is pressed and fixed into the crank body
51
at a location eccentric from the output shaft
50
a
, a reference numeral
53
denotes a connecting rod which is rotatably coupled with the driving shaft
52
and a reference numeral
54
represents a diaphragm made of a synthetic rubber or the like which is fixed to a tip of the connecting rod. Formed as an outer circumferential portion of the diaphragm
54
is a sealing portion which is sandwiched between a clamp plate
55
and a casing
66
to seal a pump chamber from external air. Furthermore, a reference numeral
61
represents a suction port, a reference numeral
62
designates a discharge port, and check valves
58
and
59
such as leaf valves are disposed in the suction port
61
and the discharge port
62
respectively.
When the motor
50
is driven and its output shaft
50
a
is rotated, the diaphragm pump which has the configuration described above rotates the crank body
51
, the driving shaft
52
moves the diaphragm
54
upward and downward by way of the connection rod
53
and, upward and downward movements of the diaphragm
54
increase and decrease a volume of the pump chamber
60
. When the volume of the pump chamber
60
is increased, the leaf valve
58
opens and a fluid is sucked through the suction port
61
and when the volume of the pump chamber
50
is decreased, the leaf valve
59
opens and the fluid is discharged from the discharge port
62
, thereby performing a pump function.
When hot water is sucked from a vessel and supplied using an impeller pump such as that shown in
FIG. 1
, air bubbles are produced in the pump. Since a vapor pressure is lower in the vicinity of a rotating center of the impeller
38
, that is, in the vicinity of the shaft
35
in particular than those in other locations in the pump chamber
33
, the produced air bubbles are collected in the vicinity of the shaft
35
, close the suction port
42
and make the hot water hardly flow, thereby remarkably lowering a hot water supply capability of the pump or disabling the pump from supplying the hot water in a worse case.
Furthermore, the impeller pump which is used for supplying hot water has a defect that the pump requires a high cost since it uses a large number of expensive parts such as two magnets of the driving magnet
40
and the follower magnet
39
as shown in
FIG. 1
to maintain sufficient airtightness.
Furthermore, a diaphragm pump such as that shown in
FIG. 2
is not disabled from supplying hot water since the pump is capable of exhausting bubbles at a certain degree even when bubbles are produced. However, the diaphragm pump has a defect that it cannot assure a sufficient reliability from a viewpoint of a service life of the diaphragm which is made of the synthetic rubber since a certain kind of synthetic rubber adds an abnormal taste or an abnormal odor to hot water and is hardened dependently on a vapor temperature or the like.
Furthermore, some of diaphragm pumps use metal diaphragms.
FIG. 3
shows an example of diaphragm pump using a metal diaphragm
70
as a diaphragm and has a configuration substantially the same as that of the diaphragm pump using the diaphragm made of the synthetic rubber shown in
FIG. 2
, except for the metal diaphragm
70
which is sandwiched and fixed between a connecting rod
53
and a retainer
71
. Accordingly, a pump function of the diaphragm pump shown in
FIG. 3
which is similar to that of the diaphragm pump shown in FIG.
2
and is performed by deforming the metal diaphragm so as to change a volume of a pump chamber.
The diaphragm pump which uses the metal diaphragm has a defect that stresses are concentrated on a middle portion of the metal diaphragm (an outer circumference of the connecting rod
53
) when the metal diaphragm is displaced largely, whereby this portion is liable to be broken and the diaphragm has an extremely short service life. In order to correct this defect, the diaphragm pump is configured large or when the pump is configured to cause a relatively short displacement of the metal diaphragm, the diaphragm pump has another defect that it cannot exhaust air bubbles sufficiently and lowers a flow rate.
Furthermore, a diaphragm pump disclosed by Japanese Patent Kokai Application No Hei 10-281070 is known as another conventional diaphragm pump.
This pump has a configuration shown in
FIG. 4
, wherein the pump comprises a pump chamber
74
formed by an upper half
71
of a pump body
70
and a diaphragm
73
, a piston
75
attached to a lower half
72
of the pump body
70
, and an operating fluid
76
sealed between the piston
75
and the diaphragm
73
.
The conventional pump shown in
FIG. 4
performs a pumping action by producing a pressure of the operating fluid with an action of the piston
75
, deforming the diaphragm
73
with the pressure, and increasing and decreasing a volume of the pump chamber.
Judging from embodiments, this diaphragm pump basically uses a liquid as the operating fluid though description is made that air (a gas) can be used as the operating fluid and the diaphragm pump basically uses a sheet of expansible and contractible synthetic resin such as teflon or synthetic rubber as the diaphragm
73
though description is made that a thin metal plate is used as the diaphragm
73
.
When a piston is used for deforming the diaphragm
73
as in this conventional example, it is important to prevent a fluid from leaking and when a liquid is used as an operating fluid in particular, prevention of liquid leakage constitutes an important theme. Accordingly, sealing of a piston section
Freay Charles G.
Oken Seiko Co., LTD
Pillsbury & Winthrop LLP
Rodriguez William
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