Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2000-02-03
2002-05-07
Thorpe, Timothy S. (Department: 3746)
Pumps
Motor driven
Electric or magnetic motor
C417S416000, C417S533000
Reexamination Certificate
active
06382935
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic diaphragm pump. More particular, this invention relates to a small-sized, light-weight electromagnetic diaphragm pump suitable for an outdoor air blower.
In general, an electromagnetic diaphragm pump comprises an oscillator, which has at its central portion two permanent magnets arranged to have mutually opposite polarities and is supported at both ends by diaphragms, and electromagnets disposed to be opposed to each other with the oscillator interposed. When an AC is supplied to the electromagnets, the polarities of the electromagnets are alternately changed according to the frequency of the AC. Consequently, the permanent magnets are attracted and repelled by the electromagnets each time the polarities of the electromagnets are changed. The diaphragms are vibrated by the axially moved oscillator.
Each diaphragm serves as a support member for the oscillator and constitutes a wall defining a compression chamber. With the vibration of the diaphragm, the volume of the compression chamber increases and decreases. Accordingly, fluid is drawn into the compression chamber via an inlet port formed in another wall which defines the compression chamber along with the diaphragm, and the fluid is discharged from an outlet.
FIGS. 19
to
21
show a specific structure of a conventional electromagnetic diaphragm pump (hereinafter referred to merely as “pump”).
FIG. 19
is a cross-sectional view showing the pump from above,
FIG. 20
is a cross-sectional side view, and
FIG. 21
is a left-hand side view of FIG.
20
.
A pump
1
has a housing constituted by a frame
2
, a soundproof cover
3
and head covers
4
,
5
arranged on the left and right sides of the frame
2
. Each of the head covers
4
and
5
is fixed to the frame
2
by four screws
4
a
,
4
b
,
4
c
,
4
d
;
5
a
,
5
b
,
5
c
,
5
d
(two screws
5
a
,
5
b
alone being shown). Core holders
6
,
7
are erected on a bottom portion of the frame
2
. Two field cores
8
,
9
having the same size are supported by the core holders
6
,
7
and fixed on the frame
2
by screws
8
a
-
8
c
;
9
a
-
9
c
. Coils
10
,
11
are wound around the field cores
8
,
9
. An oscillator
12
is provided between the field cores
8
,
9
. Since the structure for attachment of diaphragms
15
a
,
15
b
fixed to both ends of the oscillator
12
and internal structures of the head covers
4
,
5
covering the diaphragms are common on the left and right sides of the oscillator
12
, the left-hand structure alone shown in the figures will be described and a description of the right-hand structure is omitted.
A pair of center plates
13
,
14
are fixed to an end portion of the oscillator
12
. The diaphragm
15
a
is clamped between the first and second center plates
13
,
14
. The diaphragm
15
a
has a disc shape, and its outer peripheral portion, that is, a rim portion, is clamped by a ring
16
fitted in the frame
2
and the head cover
4
. Specifically, the oscillator
12
is fixed and supported at both ends by the diaphragms
15
a
,
15
b
and supported onto the frame
2
.
A compression chamber
17
defined by the diaphragm
15
a
and head cover
4
is disposed at the end portion of the oscillator
12
. A pair of inlet ports
19
for drawing air into the compression chamber
17
are formed in one of walls defining the compression chamber
17
. The inlet ports
19
are provided with plate-like valve members which are bent towards the compression chamber
17
to open the inlet ports
19
. This one of the walls is also provided with a pair of outlet ports for forcing the compressed air out of the compression chamber
17
. The outlet ports
20
are provided with plate-like valves which are bent away from the compression chamber
17
to open the outlet ports
20
.
The head cover
4
is provided with an inlet nipple
21
for drawing air and an outlet nipple
22
for discharging compressed air. An inlet chamber
23
is provided between the inlet nipple
21
and inlet ports
19
, and an outlet chamber
24
is provided between the outlet nipple
22
and outlet ports
20
. Permanent magnets
31
,
32
magnetized to have mutually opposite polarities are fixed to the oscillator
12
. An AC is supplied from an AC power supply (not shown) to the coils
10
,
11
over a cable
33
. The cable
33
is covered with a protection tube
34
, introduced into the pump
1
, divided into a plurality of coil lead wires
35
within the pump
1
, and connected to the coils
10
,
11
.
The pump
1
is fixed to a bracket
41
via legs
40
formed of elastic material, such as rubber, for vibro-isolation. The bracket
41
is attached to a desired location and the pump is driven.
When an AC with a commercial power frequency is supplied to the coils
10
,
11
over the cable
33
, the pump starts to operate. With the supply of AC, both end portions of the E-shaped main cores
8
,
9
, i.e. those portions thereof opposed to the oscillator
12
, are caused to have magnetic poles alternately with polarities for attracting and repelling the permanent magnets fixed to the oscillator
12
. The oscillator
12
vibrates in the right-and-left direction at the aforementioned commercial power frequency. In accordance with the vibration, the diaphragms
15
a
,
15
b
take in air from the inlet nipple
21
, inlet chamber
23
and inlet ports
19
and compress the air in the compression chamber
17
. The compressed air is discharged via the outlet ports
20
, outlet chamber
24
and outlet nipple
22
.
When a large discharge amount is to be obtained using the pump of the above type, it is thought to couple of a plurality of this type of pumps. For example, if two pumps each having a discharge amount of 40 l/min. are coupled, a discharge amount of 80 l/min. is obtained. Jpn. Pat. Appln. KOKAI Publication No. 61-207883 proposes an electromagnetic reciprocal pump wherein a plurality of pumps are coupled. The following problems, however, will arise if a plurality of electromagnetic diaphragm pumps are coupled.
Although a discharge amount can be increased by integrally coupling plural pumps, the size of the apparatus increases accordingly. Where a plurality of pumps are integrally coupled and used as an outdoor blower, etc., an enclosure has to be provided for preventing dropping. In such a case, in particular, the size of the apparatus including the enclosure increases and the location for installation is limited. Under the circumstance, there is a demand for reduction in size. In addition, the electrical wiring among the plural pumps becomes complex.
Besides, the diaphragms used in the pump are worn due to long-time use, and they need to be replaced with new ones periodically. In the case of the apparatus in which plural pumps are merely coupled, the housing of each pump needs to be disassembled for exchanging the diaphragms. As a result, the number of steps for maintenance increases.
Even in the case of driving a single pump, the following problems will arise.
First, since two field cores
8
,
9
of the same size, around which coils are wound, are disposed in the pump, the size of the pump increases and the weight of the pump also increases.
Second, since many screws are used to fix the field cores
8
,
9
, head covers
4
,
5
, etc. to the frame
2
, the assembly work becomes complex and the cost of the pump increases. For example, six screws (
8
a
-
8
c
;
9
a
-
9
c
) are used to fix the field cores
8
,
9
, and eight screws (
4
a
-
4
d
;
5
a
-
5
d
) are used to fix the head covers
4
,
5
.
Third, great vibration noise of the diaphragms leaks to the outside via the chamber containing the field cores
8
,
9
.
Fourth, since the size of the pump is large, as mentioned above, the buffer vessel for smoothing the pulsation of compressed air needs to be connected to the outlet nipple
22
via a pipe. This increases the size of the apparatus, makes the structure complex, and increases the cost. Moreover, the space for installation of the pump and buffer vessel increases.
BRIEF SUMMARY OF THE INVENTION
The pres
Hashimoto Atsuki
Mikiya Toshio
Mizuno Kenji
Fulbright & Jaworski L.L.P.
Nitto Kohki Co., LTD
Solak Timothy P.
Thorpe Timothy S.
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