The present invention pertains to a fluid aspiration-collection apparatus for aspirating and collecting a fluid into a suction chamber through a fluid inlet communicating with the suction chamber in the case, and for discharging the fluid through a fluid outlet after completion of fluid aspiration. A primary object of the present invention is to provide an apparatus which is simple in construction and is capable of aspirating the fluid at a constant pressure. The apparatus of the present invention comprises a case having a suction chamber formed, interior of which communicates with a fluid inlet and a fluid outlet, a moving plate constituting a part of a wall section of the suction chamber and movably disposed within the case; and a cylinder in which a piston is airtightly and movably inserted and in which a vacuum chamber is created by relative movement of the piston or itself; the piston and the moving plate being connected to move together; the cross sectional area of the piston being set smaller than the projected area in the direction of movement of the moving plate; and the back side of the piston and the moving plate communicating with the atmosphere.

FIELD OF THE INVENTION AND RELATED STATEMENT 
The present invention relates to a fluid aspiration-collection apparatus 
for aspirating and collecting a fluid including a body fluid such as blood 
and lymph generated during medical treatment or surgery for injury and 
disease, blood and secreting fluid generated in a cavity after surgery, a 
physiological saline solution after flushing an operated part or an oral 
cavity, and a waste liquid including urine and stool. 
An aspiration-collection apparatus comprising an elastic, expansible 
bellows-type container is known in the prior art as disclosed in 
Unexamined Japanese Patent Publication No. Hei 2-261472. A method of using 
the container includes pre-compressing the container before use to extrude 
the air inside, building up a negative pressure within a suction chamber 
in the container by utilizing an elastic restoring force of the container, 
sucking the liquid at a fluid inlet communicating with the suction 
chamber, and, after the collection of the fluid, compressing the container 
again to discharge the fluid filled in the suction chamber out at a fluid 
outlet. 
In the bellows-type aspiration-collection apparatus, because the elastic 
restoring force of the bellows-type container increases on the contraction 
stroke and decreases on the expansion stroke, a relatively big negative 
pressure is created in the suction chamber during the initial period of 
aspiration; however, as the container sucks the fluid and expands, the 
suction pressure gradually decreases. That is, the aspiration-collection 
apparatus has the disadvantage that fluid aspiration can not be done at a 
constant suction pressure. 
There will occur various problems if the suction pressure varies. For 
example, when the aspiration-collection apparatus is used in medical 
treatment or surgery, exudation of blood and secreting fluid from an 
affected part will be accelerated under a high suction pressure. Also 
there will arise such a disadvantage that the tissue of internal organs 
will be sucked to the opening of an aspiration tube which is connected to 
a fluid inlet, resulting in tissue trauma. In the meantime, if the suction 
pressure is too low, it will be difficult to aspirate the fluid from the 
region where suction tube is inserted, resulting in delayed recovery of 
the affected part. Therefore, this type of fluid aspiration-collection 
apparatus requires a constant suction pressure. 
An apparatus having an inflatable-expansible balloon member in a rigid 
container is used as an apparatus capable of producing as much a constant 
suction pressure as possible, as disclosed in Examined Japanese Patent 
Publication No. Sho 63-1859. This apparatus is of such a design that the 
balloon member is inflated before use to extrude the air inside the rigid 
container, and then the balloon member is allowed to contract to build up 
the negative pressure, by utilizing the shrinkage force of the balloon 
member, within the suction chamber in the rigid container. 
OBJECT AND SUMMARY OF THE INVENTION 
The above-mentioned apparatus, however, has such a disadvantage that when 
the balloon member is inflated, the surface of the member touches the 
inner surface of the rigid container, and when the balloon inflation is 
restrained, the shrinkage force of the balloon member varies as aspiration 
goes on, failing in producing a constant negative pressure. Furthermore 
the apparatus is complicated in construction and large in size, 
consequently becoming costly. 
In view of the above-described various disadvantages inherent in the 
heretofore known arts, it is an object of the present invention to provide 
a fluid aspiration-collection apparatus which can always produce a 
constant suction pressure regardless of the volume of fluid aspirated. 
The fluid aspiration-collection apparatus of the present invention 
comprises a case having a suction chamber interior which communicates with 
a fluid inlet and a fluid outlet, a moving plate constituting a part of 
the wall section of the suction chamber and movably disposed within the 
case, and a cylinder in which a piston is airtightly and movably inserted 
and in which a vacuum chamber is created by the relative movement of the 
piston itself, the piston and the moving plate being connected to move 
together, the cross sectional area of the piston being set smaller than 
the projected area in the direction of movement of said moving plate, and 
the back side of the piston and the moving plate communicating with the 
atmosphere. 
When the cylinder is movable with respect to the case (see FIGS. 1 to 8), 
the moving plate is moved to reduce the volume of the suction chamber to a 
minimum. The piston is held in contact with the closed end of the cylinder 
and with either one of the fluid inlet or the fluid outlet communicating 
with the suction chamber in communication with the atmosphere and with the 
suction chamber kept communicating with the atmosphere. In this case, 
since the moving plate and the piston are connected to move together, the 
piston and the cylinder also move with the movement of the moving plate. 
Subsequently, when the cylinder is moved while the fluid inlet and the 
fluid outlet are closed, the vacuum chamber is created within the 
cylinder. When the vacuum chamber is created, the back side of the piston 
and the moving plate are exposed to the atmosphere; and because the 
sectional area of the piston is set smaller than the projected area in the 
direction of movement of the moving plate, the moving plate and the piston 
are held in a stationary state (see FIG. 4). 
On the other hand, when the cylinder is fixedly mounted on the case (see 
FIGS. 9 and 10), and the moving plate is moved to reduce the volume of the 
suction chamber as small as possible with the piston held in contact with 
the closed end of the cylinder and with the suction chamber communicating 
with the atmosphere, the piston connected with the moving plate also moves 
in the cylinder with the movement of the moving plate, thus forming the 
vacuum chamber within the cylinder. When, after the reduction of the 
suction chamber volume to a minimum, the fluid inlet and the fluid outlet 
are closed from the atmosphere, this state will be maintained because the 
back side of the piston and the moving plate are exposed to the atmosphere 
and the sectional area of the piston has been set smaller than the 
protected area in the direction of movement of the moving plate. 
When the fluid inlet is open to the fluid to be aspirated, the fluid is 
drawn into the suction chamber and at the same time the moving plate moves 
towards increasing the volume of the suction chamber according to the 
amount of fluid to be aspirated. At this time, the negative pressure to be 
built up in the suction chamber is determined merely by the ratio of the 
sectional area of the piston to the projected area in the direction of 
movement of the moving plate, and the atmosphere, regardless of the 
quantity of fluid to be aspirated, and accordingly there is always 
produced a constant negative pressure in the suction chamber. 
To discharge the fluid collected in the suction chamber, the fluid inlet is 
closed and at the same time the fluid outlet is opened and then the moving 
plate is moved towards decreasing the volume of the suction chamber. In 
this case, the cylinder is moved towards the piston side or the air is led 
into the vacuum chamber, so that the negative pressure for pulling up the 
moving plate will be removed to permit easy discharge of the fluid. 
According to the present invention, therefore, the apparatus of simple 
construction can constantly produce a fixed negative pressure within the 
suction chamber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
First Embodiment 
A fluid aspiration-collection apparatus 1 pertaining to a first embodiment 
shown in FIGS. 1 to 4 comprises a sturdy, cylindrical case 14 having an 
upper wall 12 and a lower wall 13. The case 14 is formed of a transparent 
or semitransparent thermoplastic synthetic resin. For the synthetic resin 
there may be used an easily moldable rigid synthetic resin such as 
polyvinyl chloride, polypropylene, polyethylene, polycarbonate, etc. It 
should be noted that the case 14 is not limited in shape to the 
cylindrical type and may be for example a square-tube type. 
A round hole 15 is provided in the central part of the upper wall 12 of the 
case 14. In this round hole 15 is vertically and movably inserted a 
cylindrical cylinder 8 which is open at bottom. In this cylinder 8 a 
piston 6 is airtightly and vertically movably provided; the back side (the 
lower surface in the present embodiment) of the piston 6 communicates with 
the atmosphere. The piston 6 is provided with a seal ring 16 on the outer 
periphery so that it may slide airtightly in relation to the cylinder 8. 
When the piston 6 is moved relative to the cylinder 8 from the position in 
which the piston 6 is in contact with the upper wall 17 constituting the 
closed end of the cylinder 8, a vacuum chamber 7 is formed within the 
cylinder 8. 
To hold the piston 6 in contact with the upper wall 17 of the cylinder 8, a 
communicating port (not illustrated) communicating with both the vacuum 
chamber 7 and the atmosphere is provided in the upper wall 17 of the 
cylinder 8, and after the piston 6 is slid upwardly until it contacts the 
upper wall 17 of the cylinder 8, the communication port is closed 
airtightly by a closing means such as a plug. This closing means may be 
fixedly attached by either bonding or welding at the time of closing. 
On the cylinder 8 is provided a handle 28. The cylinder 8 and the piston 6 
are formed of a rigid synthetic resin. On the outer periphery of the lower 
end of the cylinder 8 is provided a locking projection 18 constituting a 
holding means for holding the position of the cylinder 8 relative to the 
case 14. The locking projection 18 engages the cylinder from above with 
the upper wall 12 of the case 14 when the cylinder 8 is pulled upwardly 
relative to the case 14, thus preventing the downward movement of the 
cylinder 8. A part of the round hole 15 of the case 14 is radially 
outwardly cut out as shown in FIG. 2, so that the locking projection 18 
can pass through a cutout 19. The downward movement of the cylinder 8 is 
checked by rotating the cylinder 8 after the passing of the locking 
projection 18 through the cutout 19. 
In the case 14 a disk-like moving plate 9 is vertically and movably 
installed. The moving plate 9 is fitted with seal rings on the outer 
periphery, so that the moving plate will slide airtightly relative to the 
case 14. Under the moving plate 9 is formed the suction chamber 3. That 
is, the moving plate 9 forms a part of the wall of the suction chamber 3, 
and is so designed that the volume of the suction chamber 3 increases and 
decreases with the vertical movement of the moving plate. The projected 
area S.sub.9 in the direction of movement of the moving plate 9 is set 
larger than the sectional area S.sub.6 of the piston 6, and the back side 
(the upper surface in the present embodiment) of the moving plate 9 
communicates with the atmosphere through a gap between the cylinder 8 and 
the round hole 15 of the upper wall 12 of the case 14. In the present 
embodiment, the moving plate 9 is a plate-like member and moves in the 
normal direction with respect to the bottom surface of the moving plate, 
and therefore the projected area S.sub.9 in the direction of movement of 
the moving plate 9 is equal to the sectional area of the moving plate 9 or 
the area of the bottom surface. 
The moving plate 9 and the piston 6 are connected as one unit by a 
connecting rod 20 so that they will move together. The moving plate 9, the 
piston 6 and the connecting rod 20 may be formed integrally, or may be 
fixed into one unit after being separately molded. Therefore, with the 
upward movement of the piston, the moving plate 9 also moves upwardly, 
thus increasing the volume of the suction chamber 3. 
A fluid inlet 4 and a fluid outlet 5 which communicate with the interior of 
the suction chamber 3 are provided at the lower end of the side wall of 
the case 14. To the fluid inlet is connected a flexible fluid guide tube 
21. The fluid inlet 4 can be opened and closed by sliding a plate clamp 22 
mounted on the fluid guide tube 21. On the fluid outlet a cap 23 is 
removably, airtightly, and fluid-tightly fitted. The fluid outlet 5 can be 
opened and closed by installing and removing the cap 23. Also the suction 
chamber 3 can be closed by closing the fluid inlet 4 and the fluid outlet 
5. Valve devices may be used as means for opening and closing the fluid 
inlet 4 and the fluid outlet 5. 
When the fluid aspiration-collection apparatus 1 of the present embodiment 
is used, first the moving plate 9 is pushed downwardly until it contacts 
the lower wall 13 of the case 14 as shown in FIG. 3. Then the suction 
chamber 3 is closed by closing the fluid inlet 4 and the fluid outlet 5. 
In this state, the cylinder 8 is pulled upwardly to form the vacuum 
chamber 7 as shown in FIG. 4, and the locking projection 18 of the 
cylinder 8 is set from above on the upper wall 12 of the case 14, thereby 
restraining the downward movement of the cylinder relative to the case 14. 
At this time, a downward force by the atmospheric pressure is applied to 
the cylinder 8 in an attempt to decrease the volume of the vacuum chamber 
7, but the cylinder 8, being locked by the locking projection 18 as stated 
above, is restrained from moving downwardly. 
When the suction chamber 3 is in a closed state, the piston 6 and the 
moving plate 9 which are connected in a unit, and subjected to the 
downward force Fd by the atmospheric pressure, remain stationary without 
moving upwardly. That is, let Pa be the atmospheric pressure, S.sub.6 be 
the sectional area of the piston 6, and S.sub.9 be the projected area in 
the direction of movement of the moving plate, and the force Fd will be 
obtained by the formula (1) given below. It is clear from Eq. (1) that 
there occurs the downward force because the projected area S.sub.9 in the 
direction of movement of the moving plate 9 is larger than the sectional 
area S.sub.6 of the piston. 
EQU Fd=Pa.multidot.S.sub.9 -Pa.multidot.S.sub.6 =Pa(S.sub.9 -S.sub.6)(1) 
Generally, when the apparatus of the present embodiment is used in medical 
treatment or surgery, an aspirating catheter (not illustrated) is 
connected to the forward end of the fluid guide tube 21 and is inserted 
into a treated area of a patient. The aspirating catheter may be dispensed 
with where a using condition permits. 
To aspirate the fluid, the fluid inlet 4 is opened, thus a negative 
pressure is built up in the suction chamber 3, into which the liquid 2 is 
aspirated and collected from a wound or other part of the patient as shown 
in FIG. 1. Here, provided that the absolute pressure in the suction 
chamber 3 is Pb, the relative pressure to the atmospheric pressure (Pa-Pb) 
in the suction chamber 3 is derived as the following Eq. (3) from a 
formula (2) expressing the condition of equilibrium of forces acting on 
the piston 6 and the moving plate 9 which are connected as a unit. This 
calculation was done, neglecting the sectional area of the connecting rod 
20 and the weight of the piston 6 and the moving plate 9. It is understood 
from Eq. (3) that in the suction chamber 3 there takes place a fixed 
negative pressure to be determined by the sectional area S.sub.6 of the 
piston 6, the projected area S.sub.9 in the direction of movement of the 
moving plate 9, and the atmospheric pressure Pa; the negative pressure 
being constant at all times without being changed by the amount of the 
fluid 2 aspirated. 
EQU Pa.multidot.S.sub.6 +(-Pa.multidot.S.sub.9)+Pb.multidot.S.sub.9 =0(2) 
EQU Pb-Pa=-S.sub.6 .multidot.Pa/S.sub.9 (3) 
The fluid 2 collected into the suction chamber 3 is discharged by 
disengaging the locking projection 18 of the cylinder 8 from the upper 
wall 12 of the case 14 after closing the fluid inlet 4, and then by 
pushing down the cylinder 8 with the fluid outlet 5 opened. In the prior 
art fluid aspiration-collection apparatus disclosed in Examined Japanese 
Patent Publication No. Sho 63-1859, it is likely that the outside air is 
let into the suction chamber with the discharge of the fluid, and viruses, 
various germs, etc. in the atmosphere enter the suction chamber, infecting 
the patient via the suction chamber. According to the present embodiment, 
since the outside air is hardly let into the suction chamber 3, the 
apparatus has an excellent infection prevention effect. Furthermore, if a 
scale is installed on the side wall of the case 14, the quantity of the 
fluid 2 thus aspirated can easily and accurately be read by the scale. 
Also, the apparatus, being simple in construction, can be built compactly 
and easily, whereby the scaling of the apparatus can be prevented. The 
apparatus, therefore, is excellent in portability and enables cost 
reduction. For example, in the fluid aspiration-collection apparatus 
disclosed in Examined Japanese Patent Publication No. Sho 63-1859, the 
negative pressure generating section and the fluid collecting section 
are-separately provided. However, according to the present embodiment, as 
the aspiration section and the fluid collecting section are constituted in 
one suction chamber 3, it is possible to build the apparatus smaller in 
size than the prior art fluid aspiration-collection apparatus. 
Second Embodiment 
A second embodiment is shown in FIG. 5, wherein the same members as those 
in the first embodiment are designated by the same reference numerals and 
will not be explained. 
In the fluid aspiration-collection apparatus of the present embodiment, the 
moving plate 9 does not slide in contact with the inside surface of the 
side wall of the case 14, and there is provided a cylindrical side wall 
portion 24 which constitutes the cylindrical member connecting the 
peripheral portion of the moving plate 9 with the lower wall 13 of the 
case 14. A space defined in this side wall portion 24 is the suction 
chamber 3. The side wall portion 24 is of a vertically expansible 
bellows-like structure, and therefore can increase and decrease the volume 
of the suction chamber 3 by moving the moving plate 9 vertically. Both the 
fluid inlet 4 and the fluid outlet 5 are provided in the lower wall 13 of 
the case 14, communicate with the suction chamber 3. The piston 6 is 
formed of an elastic member, such as silicone rubber, which is inserted 
slidably but airtightly in the cylinder. 
Third Embodiment 
In a third embodiment shown in FIG. 6, a difference from the second 
embodiment described above lies in the point that the cylindrical side 
wall 24 is connected to the peripheral portion of the moving plate 9 and 
the upper wall 12 of the case 14. The apparatus is similar in other points 
of constitution and therefore like members are marked alike and will not 
be explained. 
In the present embodiment, the suction chamber 3 is defined by the inner 
surface of the case, the outer peripheral surface of the side wall 24 and 
the lower surface of the moving plate 9. The quantity of fluid collected 
in the suction chamber 3 can be measured accurately by a scale provided on 
the side wall of the case 14. 
Fourth Embodiment 
In a fourth embodiment shown in FIG. 7, a difference from the third 
embodiment described hereinabove resides in that the case 14 is provided 
with a downwardly protruding recess 25 at the center of the lower wall 13, 
and that the moving plate 9 is bent so as to fit in the recess 25. 
According to the present embodiment, it is possible to accurately measure 
the aspirated quantity of the fluid 2 during the initial period of 
aspiration, and to substantially secure the maximum amount of fluid that 
can be aspirated. In medical treatment, it is important to know the 
quantity of fluid aspirated from a wounded part immediately after 
operation, and the recess 25 of the fluid aspiration-collection apparatus 
1 of the present embodiment is useful. Other points, being similar to the 
third embodiment, are marked by the same reference numerals and will not 
be explained. 
Fifth Embodiment 
In a fifth embodiment shown in FIG. 8, a difference from the fourth 
embodiment described above lies in that the cylindrical side wall 24 of a 
flexible bag type has been adopted in place of the side wall 24 of the 
bellows construction; other points of the constitution, being the same as 
the fourth embodiment, are designated by the same reference numerals and 
will not be explained in detail. 
Sixth Embodiment 
In a sixth embodiment shown in FIGS. 9 and 10, the same members as those in 
the third embodiment described hereinabove are designated by the same 
reference numerals and will not be explained in detail. An explanation 
will be given only to different constitution and effect of operation. 
In the present embodiment, the cylinder 8 is integrally secured to the 
upper wall 12 of the case 14, and an opening-closing means 11, such as a 
plug, which is capable of closing a communicating port 10 communicating 
with both the vacuum chamber 7 and the atmosphere is removably installed 
in the upper wall 17 of the cylinder 8. From the moving plate 9 four 
operating rods 30 extend upwardly, vertically movable through the upper 
wall 12 of the case 14. The top ends of these operating rods 30 are 
fixedly attached to an operating plate 31. At the fluid outlet 5 is 
installed a one-way valve 32 which allows the flow of a fluid or a gas 
from the inside of the suction chamber 3 only to the outside. 
When the fluid aspiration-collection apparatus of the present embodiment is 
used, the operating plate 31 is positioned at the top end of stroke, that 
is, the piston 6 is held in contact with the upper wall 12 of the cylinder 
8, with the communicating port 10 opened; from this state, the 
communicating port 10 is closed by the opening-closing means 11. Also, 
when the operating plate 31 is pushed downwardly with the fluid inlet 4 in 
a closed position, the air in the suction chamber 3 is discharged out at 
the one-way valve 32 mounted at the fluid outlet 5 and at the same time 
the vacuum chamber 7 is formed within the cylinder 8 owing to the relative 
movement of the piston 6 and the cylinder 8, thereby allowing the 
aspiration of the fluid 2 at a constant pressure by opening the fluid 
inlet 4. 
To discharge the fluid 2 thus collected, the fluid inlet 4 is closed first, 
and then the operating plate 31 is pushed down. At this time the moving 
plate 9 moves downwardly, decreasing the volume of the suction chamber 3 
to thereby drive the fluid 2 out at the one-way valve 32. At the same time 
the vacuum chamber 7 is formed and the fluid inlet 4 is opened to permit 
re-aspiration. The downward movement of the moving plate 9, as a matter of 
course, can be done with ease by opening the communicating port 10 to the 
atmosphere when discharging the fluid 2. 
Seventh embodiment 
In a seventh embodiment shown in FIG. 11, the same members as those in the 
first embodiment described hereinabove are designated by the same 
reference numerals and will not be explained. An explanation will be given 
only to different constitution. 
In the present embodiment, the cylinder 8 which opens in the top is 
provided as a unit on the back side of the moving plate 9 and a 
cylindrical cylinder guide section 26 is molded as a unit on the upper 
part of the case 14. On the top of the piston 6 vertically slidably 
inserted in the cylinder 8 is extendedly provided an operating rod 27, 
which protrudes upwards through the round hole 15 provided in the upper 
wall 12 of the cylinder guide section 26. On the top end of the operating 
rod 27 is provided a handle 28 as one unit. 
Next, a method of manufacturing the fluid aspiration-collection apparatus 
of the present embodiment will be briefly explained. Prior to assembling 
each member, the handle 28 is not secured to the operating rod 27; that 
is, the handle 28 is prepared as a separate member, and the lower wall 13 
of the case 14 is also not fixedly installed to the casing body. To 
assemble each member, first the cylinder 8 is molded integrally with the 
back side of the moving plate 9 and is installed so that the piston 6 
molded integrally with the operating rod 27 will be in contact with the 
bottom surface of the cylinder 8. In the moving plate 9 is formed an 
exhaust port (not illustrated) communicating with the interior of the 
cylinder 8. After the insertion of the piston 6, the exhaust port will be 
closed. After the installation, in the casing body, of the moving plate 9 
and the cylinder 8 into which the piston 6 has been inserted, the lower 
wall 13 is secured by welding or the like. At this time the operating rod 
27 protrudes out of the round hole 15. On the top end of the operating rod 
27 which extrudes, the handle 28 is fixedly attached by welding or the 
like. 
According to the present embodiment, when the operating rod 27 is pulled up 
with the fluid inlet 4 and the fluid outlet 5 is closed, the vacuum 
chamber 7 is created within the cylinder 8. When the locking projection 18 
projectingly provided on the operating rod 27 has appeared above the upper 
surface of the cylinder guide section 26, the operating rod 27 is rotated 
to lock the locking projection 18 on the upper surface of the cylinder 
guide section 26, thereby holding the operating rod 27 and accordingly the 
piston 6 in a specific position. The following operation is the same as 
that of the first embodiment. 
Eighth Embodiment 
In an eighth embodiment shown in FIGS. 12 and 13, the same members as those 
in the third embodiment described hereinabove are designated by the same 
reference numerals and will not be explained. An explanation will be given 
only to different constitution and effect of operation. 
In the present embodiment, the apparatus has four sets of pistons 6 and 
cylinders 8. Each of the pistons 6 is integrally connected with the moving 
plate 9 and each of the cylinders 8 is inserted in the round hole 15 
provided in the upper wall 12 of the case 14. At the upper part of each 
cylinder 8 is formed a flange section 33, which is rotatably mounted on 
the connecting plate 34. The four cylinders 8 can be pulled upwardly all 
together by pulling the handle 28 of the connecting plate 34 upwardly. At 
this time, the locking projection 18 passes through the cutout 19 provided 
in the inner periphery of the round hole 15 of the upper wall 12. Then, 
each cylinder 8 is rotated to move the locking projection 18 into 
engagement with the upper wall 12 of the case 14. At the center of the 
upper wall 17 of each cylinder 8 is provided a communicating hole 10 which 
is open to the atmosphere; in this communicating hole 10 the plug-like 
opening-closing means 11 is fitted airtightly. 
It is advisable that the locking projection 18, as shown in FIG. 14, be so 
constituted as to be elastically movable in a radial direction, and be 
provided, at the top end, with a taper surface 18A which contacts the 
inner surface of the cutout 19 to deform the locking projection 18 
radially inwardly. In the apparatus of the above-described constitution, 
the locking projections 18 of the four cylinders 8 can be engaged with the 
cutouts 19 of the case 14 merely by pulling up the handle 28 of the 
connecting plate 34. To disengage, the locking projections 18 is simply 
pushed radially inwardly. The constitution of the locking projection 18 
shown in FIG. 14 can be adopted also in each of the embodiments described 
hereinabove. The communicating port 10 and the opening-closing means 11 
are not required to be provided in all of the cylinders 8, but are 
sufficient if provided in at least one of the cylinders 8. 
According to the present embodiment, suction pressure adjustment on the 
whole can be done by opening and closing the communicating port 10 by the 
opening-closing means 11 pursuant to necessity. In the present embodiment, 
the cylinders 8 are connected each to the connecting plate 34, but may be 
so constituted as to be pulled up separately without the provision of the 
connecting plate 34. In this case, aspiration is done with the fluid inlet 
4 opened after forming the vacuum chamber 7 by pulling up as many 
cylinders 8 as required. 
It should be noted that each embodiment of the present invention explained 
hereinabove is not limited thereto and design changes are possible within 
the scope of the present invention. For example, the piston 6 and the 
moving plate 9 in the described embodiments are connected With each other 
by the connecting rod 20, but may be connected by a wire-like material 
such as a string, wire, and so forth. It also should be noticed that the 
fluid aspiration-collection apparatus of the present invention is not 
limited to the embodiments for medical use explained above and is usable 
for various other purposes.