U.S. patent application number 13/582100 was filed with the patent office on 2012-12-27 for dispenser for highly viscous fluid.
Invention is credited to Toru Imaizumi, Kouichi Ozaki.
Application Number | 20120325864 13/582100 |
Document ID | / |
Family ID | 44246274 |
Filed Date | 2012-12-27 |
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United States Patent
Application |
20120325864 |
Kind Code |
A1 |
Imaizumi; Toru ; et
al. |
December 27, 2012 |
Dispenser For Highly Viscous Fluid
Abstract
The present invention relates to a dispenser for discharging a
highly viscous fluid which possesses a viscosity ranging from 10 to
1,000 Pas at 25.degree. C. and contains filler particles, the
dispenser comprising: (i) a highly viscous fluid-supply part (A)
equipped with a container (3) containing said highly viscous fluid
(M) and possessing an outlet (3a) of said highly viscous fluid, a
plunger (2) capable of discharging said highly viscous fluid from
said outlet by pressing said highly viscous fluid contained in said
container, and a servomotor (4) driving said plunger; and (ii) a
highly viscous fluid-discharge part (B) equipped with a pipe (7)
arranged for delivering said highly viscous fluid discharged from
said outlet, an openable and closable valve (8) connected to said
pipe, and a discharge port (9) for discharging said highly viscous
fluid. The dispenser according to the present invention can stably
discharge a specified amount of a highly viscous fluid containing
filler particles for a long period of time, and can be used even in
a clean room.
Inventors: |
Imaizumi; Toru;
(Ichihara-shi, JP) ; Ozaki; Kouichi; (Tokyo,
JP) |
Family ID: |
44246274 |
Appl. No.: |
13/582100 |
Filed: |
February 9, 2011 |
PCT Filed: |
February 9, 2011 |
PCT NO: |
PCT/JP2011/053309 |
371 Date: |
August 31, 2012 |
Current U.S.
Class: |
222/333 |
Current CPC
Class: |
B05C 5/0225 20130101;
H01L 21/54 20130101; B05C 11/1013 20130101; B05C 5/0212 20130101;
B05C 11/1034 20130101 |
Class at
Publication: |
222/333 |
International
Class: |
B65D 83/76 20060101
B65D083/76 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 2010 |
JP |
2010-046768 |
Claims
1. A dispenser for discharging a highly viscous fluid which
possesses a viscosity ranging from 10 to 1,000 Pas at 25.degree. C.
and contains filler particles, the dispenser comprising: (i) a
highly viscous fluid-supply part equipped with a container
containing said highly viscous fluid and possessing an outlet of
said highly viscous fluid, a plunger capable of discharging said
highly viscous fluid from said outlet by pressing said highly
viscous fluid contained in said container, and a servomotor driving
said plunger; and (ii) a highly viscous fluid-discharge part
equipped with a pipe arranged for delivering said highly viscous
fluid discharged from said outlet, an openable and closable valve
connected to said pipe, and a discharge port for discharging said
highly viscous fluid.
2. The dispenser according to claim 1, further comprising a
converting mechanism for converting a rotation drive of said
servomotor into a linear drive.
3. The dispenser according to claim 1, further comprising a packing
provided between said plunger and said container.
4. The dispenser according to claim 1, which can control the
opening and closing of said valve and/or driving of said servomotor
by detecting a pressure exerting on said highly viscous fluid.
5. The dispenser according to claim 1, which can control a
discharged amount of said highly viscous fluid by controlling the
opening and closing of said valve and/or driving of said servomotor
by detecting a pressure exerting on said highly viscous fluid.
6. The dispenser according to claim 1, wherein a single amount
discharged of said highly viscous fluid ranges from 1 to 10 g.
7. The dispenser according to claim 1, wherein a part of said
container and/or said plunger contacting at least said highly
viscous fluid is abrasion-resistant.
8. The dispenser according to claim 1, wherein said filler
particles comprise at least one selected from the group consisting
of metals, inorganic oxides, inorganic nitrides, and inorganic
carbides.
9. The dispenser according to claim 1, wherein an amount of said
filler particles ranges from 50 to 99% by mass with respect to the
total mass of said highly viscous fluid.
10. The dispenser according to claim 1, wherein said highly viscous
fluid is a silicone grease.
11. The dispenser according to claim 8, wherein an amount of said
filler particles ranges from 50 to 99% by mass with respect to the
total mass of said highly viscous fluid.
12. The dispenser according to claim 11, wherein said highly
viscous fluid is a silicone grease.
Description
TECHNICAL FIELD
[0001] The present invention relates to a dispenser which can
supply a specified amount of a highly viscous fluid and use
thereof.
[0002] Priority is claimed on Japanese Patent Application No.
2010-46768, filed on Mar. 3, 2010, the content of which is
incorporated herein by reference.
BACKGROUND ART
[0003] Electronic devices such as semiconductor devices and the
like produce heat during use. For this reason, in order to prevent
damage or performance degradation caused by increased temperatures
to the electronic devices, it is necessary to remove heat from the
electronic devices.
[0004] As a means for removing heat from electronic devices, for
example, conducting heat from heating elements such as
semiconductor elements and the like in the electronic devices to a
radiator such as a heat pipe, a heatsink or the like has been
widely carried out. In addition, in order to effectively conduct
the heat from the heating element to the radiator, for example, a
grease having thermal conductivity is applied between the heating
element and the radiator.
[0005] As described in Japanese Unexamined Patent Application,
First Publication No. 2008-19426, Japanese Unexamined Patent
Application, First Publication No. 2008-274036, and Japanese
Unexamined Patent Application, First Publication No. 2007-99821, a
silicone grease having thermal conductivity contains a relatively
large amount of filler particles comprising a material having
thermal conductivity such as zinc oxide, aluminum oxide or the
like, in a silicone oil base, and possesses an increased viscosity.
In addition, it is necessary to accurately apply a small amount of
the aforementioned grease between a radiator and a fine heating
element such as a semiconductor element or the like. Therefore, the
aforementioned grease is usually applied by means of a dispenser
equipped with a pump controllable by means of, for example, a
computer or the like.
DISCLOSURE OF INVENTION
Technical Problems
[0006] The filler particles are relatively hard. For this reason,
when a silicone grease containing the filler particles is applied
by means of a dispenser, the inner part of the dispenser is easily
abraded with the filler particles. Therefore, the aforementioned
grease may leak in a short time from, for example, a pump part of
the dispenser due to abrasion. Thereby, there are inconveniences
that include not only difficulties in supplying a specified amount
of a grease by means of a dispenser, but also contamination of the
surrounding environment of the dispenser with the aforementioned
leaked grease. In addition, an instrument in which the
aforementioned contamination may occur cannot be used in, for
example, a clean room at which the preparation of electronic
devices is carried out.
[0007] In addition, in the case of using a dispenser having an oil
hydraulic drive mechanism in order to apply a highly viscous
silicone grease, there is usually a risk of oil leaking, and the
environment may be contaminated. Therefore, a device of an oil
hydraulic drive type in which a risk of oil leaking even with an
extremely small amount is present cannot be used in, for example, a
clean room.
[0008] The present invention has an objective to provide a
dispenser which can stably discharge a specified amount of a highly
viscous fluid containing filler particles for a long period of
time, and can be used even in a clean room.
Technical Solution
[0009] The objective of the present invention can be achieved by a
dispenser for discharging a highly viscous fluid which possesses a
viscosity ranging from 10 to 1,000 Pas at 25.degree. C. and
contains filler particles, the dispenser comprising: [0010] (i) a
highly viscous fluid-supply part equipped with a container
containing said highly viscous fluid and possessing an outlet of
said highly viscous fluid, a plunger capable of discharging said
highly viscous fluid from said outlet by pressing said highly
viscous fluid contained in said container, and a servomotor driving
said plunger; and [0011] (ii) a highly viscous fluid-discharge part
equipped with a pipe arranged for delivering said highly viscous
fluid discharged from said outlet, an openable and closable valve
connected to said pipe, and a discharge port for discharging said
highly viscous fluid.
[0012] The dispenser of the present invention is preferably
equipped with a conversion mechanism for converting a rotary drive
of said servomotor into a linear drive.
[0013] The dispenser of the present invention is preferably
equipped with a packing between said plunger and said
container.
[0014] The dispenser of the present invention is preferably capable
of controlling the opening and closing of said valve and/or driving
of said servomotor by detecting a pressure exerting on said highly
viscous fluid. In particular, a discharged amount of said highly
viscous fluid can preferably be controlled by means of controlling
the opening and closing of said valve and/or driving of said
servomotor.
[0015] The single amount discharged of said highly viscous fluid
preferably ranges from 1 to 10 g.
[0016] In the dispenser of the present invention, the part of said
container and/or said plunger contacting at least said highly
viscous fluid is preferably abrasion-resistant.
[0017] Said filler particles comprise at least one selected from
the group consisting of metals, inorganic oxides, inorganic
nitrides, and inorganic carbides. In addition, an amount of said
filler particles preferably ranges from 50 to 99% by mass with
respect to the total mass of the highly viscous fluid.
[0018] Said highly viscous fluid is preferably a silicone
grease.
Advantageous Effects
[0019] The dispenser of the present invention can stably discharge
a specified amount of a highly viscous fluid containing filler
particles for a long period of time, and can be used even in a
clean room. Therefore, the dispenser of the present invention can
be suitably used in the preparation of electronic devices in a
clean room. In particular, the dispenser of the present invention
can accurately discharge a highly viscous fluid even in a small
amount by means of accurate electrical drive control with a
servomotor. For this reason, a small amount of the highly viscous
fluid can be accurately applied between a heating element and a
radiator, and thereby, a radiator structure for use in an
electronic device can be easily produced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a schematic view showing an embodiment of a
dispenser of the present invention.
BEST MODES FOR CARRYING OUT THE INVENTION
[0021] One mode of the present invention is a dispenser for a
highly viscous fluid containing filler particles.
[0022] The filler particles are preferably formed from a material
possessing thermal conductivity. The material may be a single type
one or be combined with two or more types thereof. As examples of
materials forming said filler particles, mention may be made of,
for example, metals such as aluminum, gold, silver, copper, nickel,
iron and the like; inorganic oxides such as aluminum oxide, zinc
oxide, nickel oxide, titanium oxide, silicon oxide, vanadium oxide,
copper oxide, iron oxide, silver oxide and the like; inorganic
nitrides such as aluminum nitride, boron nitride, silicon nitride
and the like; inorganic carbides such as silicon carbide, carbon,
diamond and the like; and mixtures thereof. The material forming
the filler particles is preferably an inorganic oxide, and more
preferably a metal oxide such as aluminum oxide, zinc oxide or the
like.
[0023] The blending amount of the filler particles is not
particularly restricted. In general, if the amount is remarkably
reduced, thermal conductivity may be reduced. On the other hand, if
the blending amount is remarkably increased, thermal conductivity
can be improved, but a viscosity of the highly viscous fluid may be
increased, and poor operationability may be exhibited. Therefore,
although the blending amount of the filler particles may vary
depending on the types of the materials, the amount may range from
50 to 99% by mass, preferably ranges from 60 to 98% by mass, more
preferably ranges from 70 to 97% by mass, and furthermore
preferably ranges from 80 to 96% by mass, with respect to the total
mass of the highly viscous fluid.
[0024] Said highly viscous fluid has a viscosity at 25.degree. C.
ranging from 10 to 1,000 Pas and preferably ranging from 100 to 500
Pas. If the viscosity is below 10 Pas, dripping of the fluid may
easily occur. On the other hand, if the viscosity exceeds 1,000
Pas, discharging properties may be reduced, and for this reason,
handling properties of the fluid may become poor. The viscosity is
measured by means of a rheometer.
[0025] Said highly viscous fluid preferably exhibits a grease
property, and in particular, is preferably a grease possessing
thermal conductivity. In addition, said grease preferably possesses
a coefficient of thermal conductivity measured at 25.degree. C. by
means of a hot wire method which is preferably 0.5 W/mK or more,
more preferably 1.0 W/mK or more, and in particular, preferably 2.0
W/mK or more.
[0026] In the case where said highly viscous fluid is a grease, as
examples of a base oil forming the grease together with said filler
particles and the like, mention may be made of mineral oil-based
ones such as paraffin oils and naphthene oils; synthetic ones such
as .alpha.-olefin polymers or oligomers, polyalkylene glycol,
diesters (dibasic acid esters), trimellitic acid esters, polyol
esters, perfluoro polyethers, polyphenyl ethers, silicones, and the
like. In view of electrical insulation properties and thermal
resistance, the base oil is preferably a silicone. Therefore, said
highly viscous fluid is preferably a silicone grease in which a
silicone is used as a base oil.
[0027] The aforementioned silicone greases are, in general,
commercially available. As examples thereof, mention may be made
of, for example, SC4471CV, SC4490CV, TC-5021, TC-5022, and TC-5351,
manufactured by Dow Corning Toray Co., Ltd.
[0028] The dispenser of the present invention can be used in order
to discharge the aforementioned highly viscous fluid. Namely, the
dispenser of the present invention is a dispenser for discharging a
highly viscous fluid which has a viscosity at 25.degree. C. ranging
from 10 to 1,000 Pas and preferably ranging from 100 to 500 Pas,
and contains filler particles.
[0029] The dispenser of the present invention contains [0030] (1) a
highly viscous fluid-supply part equipped with a container
containing said highly viscous fluid and possessing an outlet of
said highly viscous fluid, a plunger capable of discharging said
highly viscous fluid from said outlet by pressing said highly
viscous fluid contained in said container, and a servomotor driving
said plunger; and [0031] (2) a highly viscous fluid-discharge part
equipped with a pipe arranged for delivering said highly viscous
fluid discharged from said outlet, an openable and closable valve
connected to said pipe, and a discharge port for discharging said
highly viscous fluid.
[0032] One of the characteristics of the dispenser of the present
invention is that when the dispenser discharges the highly viscous
fluid containing filler particles, the dispenser employs no
mechanism of pumping a fluid by means of an operation of a rotator
such as a conventional pump.
[0033] In the conventional pump using a rotator, the rotator itself
and a sealing part of said rotator are rapidly abraded away by
contacting with the filler particles, and therefore, it is
difficult to accurately supply said viscous fluid. In addition,
when abrasion further proceeds, said highly viscous fluid is leaked
from the pump, and the environment may be contaminated.
[0034] In contrast, the dispenser of the present invention delivers
the highly viscous fluid containing filler particles under pressure
by means of not a rapidly-rotating rotator, but a plunger which
carries out a linear movement. Thereby, in the dispenser of the
present invention, a part contacting said highly viscous fluid
containing filler particles is restricted to the tip periphery of
the plunger. In addition, the plunger does not rapidly rotate, and
for this reason, a relative speed of the highly viscous fluid and
the plunger at the time of contacting them can be controlled.
Therefore, it is difficult to abrade the dispenser of the present
invention even if the dispenser contacts the highly viscous fluid
containing filler particles, and there is no difficulty of
volumetric or gravitmeric feeding of said highly viscous fluid due
to abrasion caused by filler particles.
[0035] In addition, another characteristic of the dispenser of the
present invention is that the dispenser is not operated by means of
an oil hydraulic drive mechanism.
[0036] In general, not only in the oil-hydraulic drive-control, but
also in the liquid-hydraulic drive-control, power is led via a
liquid, and for this reason, a slight time lag for leading power
occurs. In addition, properties such as viscosity of the liquid may
vary depending on temperatures, and performance may be affected.
Therefore, in a usage in which high accuracy is required, for
example, at the time of the preparation of an electronic device, it
is difficult to control a discharged amount with a required degree
of accuracy in an oil-hydraulic dispenser. In particular, as the
discharged amount is reduced, it is extremely difficult to maintain
a specified amount which is discharged.
[0037] Therefore, in the dispenser of the present invention, a
plunger is drive-controlled by means of an electric drive mechanism
using a servomotor. The servomotor is completely electrically
drive-controlled, and for this reason, the plunger can be extremely
accurately driven. Therefore, even in the usage of the preparation
of an electronic device, a discharged amount can be controlled with
a high degree of accuracy even if the discharged amount is small.
In addition, a liquid such as oil is not used, and for this reason,
the dispenser of the present invention can be used even in a clean
room. In addition, the electric drive-control is superior to the
oil-hydraulic drive-control, in view of energy effectiveness.
[0038] Therefore, the dispenser of the present invention can
discharge a specified amount of a highly viscous fluid containing
filler particles for a long period of time by virtue of delivering
under pressure with a plunger which is abrasion-resistant and using
an electric drive-control with a servomotor, and the dispenser can
also be used even in a clean room.
[0039] For delivering a highly viscous fluid such as grease
containing filler particles under pressure, a large output power is
in general required, and for this reason, an oil-hydraulic
drive-control which can easily obtain a large output power is
usually used. In contrast, the dispenser of the present invention
tends to discharge a highly viscous fluid in a relatively small
amount such as about 1 to 10 g, and for this reason, a discharge
power can be sufficiently obtained by means of drive due to a
servomotor.
[0040] In the servomotors, there are a rotation drive-type
servomotor and a linear drive-type servomotor (linear servomotor).
In the case of using the linear servomotor, the linear servomotor
can be directly connected with the plunger. In the case of using
the rotation drive-type servomotor, a converting mechanism such as
a screw jack, ball screw or the like for converting the rotation
drive of the servomotor into the linear drive is preferably
equipped.
[0041] Next, modes for using the dispenser of the present invention
are described with reference to the drawings. FIG. 1 is a schematic
view showing one embodiment of a dispenser of the present
invention.
[0042] A dispenser shown in FIG. 1 is equipped with a
pressure-resistant container 3 for containing highly viscous fluid
M such as a grease containing filler particles in a casing 1. Said
pressure-resistant container 3 possesses an outlet 3a at the
vicinity of a bottom face thereof. In the embodiment shown in FIG.
1, one outlet 3a is provided, but plural outlets may be
present.
[0043] In the embodiment shown in FIG. 1, said pressure-resistant
container 3 is in the form of a cylinder of which the upper end
face is open. A plunger 2 provided with an end part 2a in the form
of a cylinder coinciding with the inner peripheral form of said
pressure-resistant container 3 is engaged in said
pressure-resistant container 3 so that said highly viscous fluid M
contained in said pressure-resistant container can be pressed from
said upper end face. A shaft 2b of said plunger 2 is held by a
screw jack 6 so that said plunger 2 can be freely moved vertically.
Said shaft 2b passes through the inner face of said maintained
casing 1 via the opening of said casing 1, which is not shown in
the drawing.
[0044] Said screw jack 6 is connected to a rotation drive axis of
said servomotor 4 of rotation drive type via a coupling 5, and the
rotation drive of said servomotor 4 can be transmitted to said
screw jack 6 from said axis via coupling 5. Said servomotor 4 can
be controlled by means of controlling system which is not shown in
the drawing. Said screw jack 6 functions as a conversion mechanism
of converting the rotation drive of the servomotor into a linear
drive and transmitting to said plunger 2. As said conversion
mechanism is not restricted to a screw jack, a ball screw or the
like may be used, for example.
[0045] In the embodiment shown in FIG. 1, said pressure-resistant
container 3, plunger 2, and servomotor 4 constitute a highly
viscous fluid supply part A.
[0046] In order to enhance liquid-tight properties, a packing is
preferably provided at a part contacting said plunger 2 and
pressure-resistant container 3. The material for the packing is not
particularly restricted. In order to prevent abrasion caused by
contacting filler particles in said highly viscous fluid M, at
least the surface of the packing is preferably formed from an
abrasion-resistant material.
[0047] Since said pressure-resistant container 3 and the end part
2a of said plunger 2 are parts contacting said highly viscous fluid
M containing filler particles, at least the inner peripheral
surface of said pressure-resistant container 3 and the surface of
said end part 2a are preferably formed from abrasion-resistant
materials. The abrasion-resistant materials are not particularly
restricted, and conventionally known abrasion-resistant materials
such as high-chromium steel, various hard ceramics and the like can
be used therefor.
[0048] In addition, the dispenser shown in FIG. 1 possesses a pipe
7 connected to said outlet 3a of said pressure-resistant container
3, for delivering said highly viscous fluid M discharged from said
outlet 3a. Manometers 10, 11 for measuring the pressure in said
pipe 7 are respectively provided at the beginning end periphery and
the terminal end periphery. Said manometers 10, 11 are connected to
a control system which is not shown in the drawing. On the basis of
the results measured by said manometers 10, 11, said servomotor 4
can be drive-controlled. Said pipe 7 is connected to a valve 8
equipped with a nozzle 9 for discharging said highly viscous fluid
M, and said highly viscous fluid M delivered by said pipe 7 can be
discharged via said valve 8 and nozzle 9. It is not necessary to
integrate said valve 8 and nozzle 9, and they can be arranged at
any part of said pipe 7. In order to accurately control a
discharged amount, said valve 8 is preferably provided at the place
closest to said nozzle 9 as possible.
[0049] In the embodiment shown in FIG. 1, said pipe 7, valve 8 and
nozzle 9 constitute a highly viscous fluid-discharge part B.
[0050] In the case of discharging said highly viscous fluid M using
said dispenser shown in FIG. 1, first, said highly viscous fluid M
is fed in said pressure-resistant container 3. In the embodiment
shown in FIG. 1, said plunger 2 is pulled up to open the upper end
face of said pressure-resistant container 3, and said highly
viscous fluid M containing filler particles is fed in said
pressure-resistant container 3 from a feeding means which is not
shown in the drawing. A feeding port may be provided in said
pressure-resistant container 3, and said highly viscous fluid M may
be fed in said pressure-resistant container 3 from said feeding
port. In this case, it is not necessary to open said upper end
face, and for this reason, the possibility of mixing contaminants
from the outer world in said highly viscous fluid M can be
prevented.
[0051] Next, said servomotor 4 is driven by a signal from said
controlling means which is not shown in the drawing, said plunger 2
is pushed in said pressure-resistant container 3, and the highly
viscous fluid in said pressure-resistant container 3 is pressed and
extruded. Thereby, said highly viscous fluid M is discharged from
said outlet 3a of said pressure-resistant container 3 to said pipe
7. In addition, said highly viscous fluid M discharged from said
outlet 3a is delivered under pressure in said pipe 7, and
discharged from said nozzle 9 via said valve 8.
[0052] The pressure of said highly viscous fluid M in said pipe 7
is detected by means of manometers 10, 11, and transferred to said
controlling system. In the embodiment shown in FIG. 1, on the basis
of the information transferred to said controlling system, said
servomotor 4 and/or valve 8 are drive-controlled. For example,
while said valve 8 is opened, in order to compensate pressure
reduction of said highly viscous fluid M, pressing power of said
plunger 2 is increased by increasing the number of revolutions of
said servomotor 4. On the other hand, while said valve 9 is closed,
pressing power of said plunger 2 is reduced by reducing the number
of revolutions of said servomotor 4. Thereby, while said valve 8 is
opened, the pressure of said highly viscous fluid M is maintained
to a targeted level, and the discharged amount can be controlled to
a specified amount. Thereby, the amount of said highly viscous
fluid M discharged from said nozzle 9 can be accurately controlled.
The single discharged amount of said highly viscous fluid M from
said nozzle 9 is not particularly restricted, and preferably ranges
from 1 to 10 g and may range from 1 to 5 g.
[0053] A thermometer may be set in said pressure-resistant
container 3 and/or pipe 7 to detect the temperature of said highly
viscous fluid M, and on the basis of the results obtained by the
measurements, the revolutions of said servomotor 4 and/or opening
and closing of said valve 8 may be controlled.
[0054] As described above, the dispenser of the present invention
can be used in a clean room, and for this reason, the dispenser can
be preferably used in the preparation of an electronic device
equipped with various radiation constructions carried out in a
clean room.
[0055] In particular, the dispenser of the present invention can
accurately discharge a highly viscous fluid for a long time even in
a small amount by means of accurate electronic drive-control using
a servomotor. For this reason, a radiation construction required
for use in an electronic device can be produced with high
accuracy.
EXAMPLES
[0056] Hereinafter, the present invention is described in detail
with reference to examples and comparative examples. It should be
understood that the present invention is not restricted to the
examples.
Example 1
[0057] A silicone grease (TC-5351, manufactured by Dow Corning
Toray Co., Ltd.) having a thermal conductivity of 2.9 W/mK was
intermittently discharged by means of the dispenser shown in FIG.
1. The viscosity thereof was measured by means of a rheometer (AR
550, manufactured by TA Instruments) under the condition of
geometry: parallel plate with a diameter of 20 mm, gap: 200 .mu.m,
and shear rate: 10.0 (1/s). As a result, the viscosity of said
silicone grease at 25.degree. C. was 318 Pas.
[0058] More particularly, said servomotor 4 was driven and while
the silicone grease in said pressure-resistant container 3 is
pressed by means of said plunger 2, said valve 8 was opened for 15
seconds. During this, the weight of the grease discharged from said
nozzle 9 was measured, and discharge stability was evaluated. The
dischargements of said silicone grease were carried out 4,000
times. The results are shown in Table 1.
TABLE-US-00001 TABLE 1 Initial 9.5 hours 22 hours stage elapsed
elapsed Minimum amount 3.583 3.593 3.458 discharged (g) Maximum
amount 3.614 3.611 3.51 discharged (g) (Maximum amount 0.031 0.018
0.052 discharged) - (Minimum amount discharged) (g) Average (g)
3.604 3.602 3.485 Standard deviation 0.008 0.0048 0.0095
[0059] Subsequently, discharging was carried out until 500 hours
elapsed. As a result, no problems such as leakage of the grease at
the supply part of the highly viscous fluid of the dispenser were
found.
Comparative Example 1
[0060] The change of a discharged amount of the silicone grease
over time was evaluated in the same manner as described in Example
1, using a dispenser which was the same as that used in Example 1,
with the exception of replacing the supply part of the highly
viscous fluid in FIG. 1 with a pail pump (manufactured by Taiyo
Techno Ltd.). After 300 hours elapsed from the stat of the
evaluation, leakage of the silicone grease from the shaft of the
pail pump was remarkably observed. After 475 hours, a large amount
of leakage was observed. As a result of analyses of the shaft and
the packing in the vicinity of the shaft, considerable abrasion
occurred at both the shaft and the packing.
Comparative Example 2
[0061] The change of a discharged amount of the silicone grease
over time was evaluated in the same manner as described in Example
1, using a dispenser which was the same as that used in Example 1,
with the exception of replacing said servomotor 4 as the drive
means of said plunger 2 in FIG. 1 with an oil hydraulic cylinder.
The results are shown in Table 2.
TABLE-US-00002 TABLE 2 Initial stage Minimum amount 4.00 discharged
(g) Maximum amount 4.11 discharged (g) (Maximum amount 0.11
discharged) - (Minimum amount discharged) (g) Average (g) 4.07
Standard deviation 0.0346
[0062] It can be seen that in Comparative Example 2, the discharged
amounts largely varied even in the initial stage of the
discharging, as compared with Example 1. Therefore, it is difficult
to accurately provide a specified amount of a highly viscous
silicone grease with a hydraulic drive system.
INDUSTRIAL APPLICABILITY
[0063] The dispenser of the present invention can be suitably used,
for example, in the preparation of an electronic device in a clean
room. In particular, the dispenser of the present invention can be
suitably used in the preparation of an electronic device containing
a radiation structure in which a grease having thermal conductivity
is present between a heating element such as a semiconductor
element or the like and a radiator such as a heat pipe, a heatsink,
or the like.
DESCRIPTION OF SYMBOLS
[0064] 1: Casing, 2: Plunger, 3: Pressure-resistant container, 4:
Servomotor, 5: Coupling, 6: Screw jack, 7: Pipe, 8: Valve, 9:
Nozzle, 10,11: Manometers.
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