Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2002-07-11
2004-06-29
Yu, Justine R. (Department: 3746)
Pumps
Motor driven
Electric or magnetic motor
C417S313000, C062S118000
Reexamination Certificate
active
06755626
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a miniature pump that can be used in a cooling system or the like. It relates in particular to a miniature pump with improved stable-discharge characteristics. Furthermore, the present invention relates to a cooling system and portable equipment using such a miniature pump.
2. Description of Related Art
In conventional diaphragm type miniature pumps, their sizes have been reduced considerably by adopting a vibrating plate made of a piezoelectric element, for example, PZT.
FIG. 18
shows an example thereof.
In this figure, numeral
300
denotes a piezoelectric vibrating plate including a piezoelectric substrate
310
and a vibrating plate
320
, numeral
330
denotes suction and exhaust valves for controlling a liquid flow, and numeral
340
denotes a casing forming a pressure chamber
500
and a flow passage. The piezoelectric substrate
310
is attached to the vibrating plate
320
so as to form the piezoelectric vibrating plate
300
serving as a diaphragm. An AC voltage is applied to the piezoelectric substrate
310
of this piezoelectric vibrating plate
300
, thereby concaving or convexing the piezoelectric vibrating plate
300
. The resulting change in volume of the pressure chamber
500
and the resulting movement of the valves
330
bring about a pumping function.
Next, the movement of the valves and that of the piezoelectric vibrating plate during suction and exhaustion will be described more specifically referring to
FIGS. 19A and 19B
. In these figures, arrows
10
indicate a liquid flow direction.
FIG. 19A
shows a sucking operation of the miniature pump, and
FIG. 19B
shows a discharging operation thereof. As shown in these figures, an AC voltage is applied to the piezoelectric vibrating plate
300
so as to deform it toward the direction that increases the volume of the pressure chamber
500
, thereby sucking a fluid through a suction valve
330
a
into the pressure chamber
500
(see FIG.
19
A). Also, the application of an AC voltage causes the piezoelectric vibrating plate
300
to deform in the direction that decreases the volume of the pressure chamber
500
, thereby discharging the fluid, which has been sucked into the pressure chamber
500
, from a discharge port through an exhaust valve
330
b
(see FIG.
19
B).
However, although the above-described conventional diaphragm type miniature pumps can be made much smaller than those converting a rotational motion of a motor into a reciprocating motion using a motion converter so as to drive a diaphragm, it is difficult to increase the area of the diaphragm. Accordingly, when it comes to a pumping performance, the discharge flow rate has been rather small. For example, in the case where a unimorph type piezoelectric vibrating plate with a diameter of 25 mm was used as a driving source and driven at an AC voltage of 100 V rms, only a flow rate of about 30 cm
3
/min was obtained with respect to 60 Hz driving.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a miniature pump that achieves both a large discharge flow rate and stable discharge flow rate characteristics, and a cooling system and portable equipment using this miniature pump.
In order to achieve the above-mentioned object, a miniature pump of the present invention includes a miniature pump portion including a suction passage through which a liquid flows in, and a discharge passage through which the liquid flows out; and a bubble trap portion for blocking an entry of air bubbles into the miniature pump portion.
REFERENCES:
patent: 3833013 (1975-09-01), Leonard
patent: 3951147 (1976-04-01), Tucker et al.
patent: 4604090 (1986-08-01), Reinicke
patent: 4728969 (1988-03-01), Le et al.
patent: 5349499 (1994-09-01), Yamada et al.
patent: 5764483 (1998-06-01), Ohashi et al.
patent: 6485275 (2002-11-01), Takeuchi et al.
patent: 0 465 229 (1992-01-01), None
patent: 7-142886 (1995-06-01), None
Adachi Yusuke
Imada Katsumi
Komatsu Atsushi
Ninomiya Toru
Okano Masayuki
Merchant & Gould P.C.
Rodriguez William H.
Yu Justine R.
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