Therapeutic suction device

A therapeutic suction device includes an operating vacuum chamber connected to a motor operated pump to create a vacuum pressure therein and a pressure controlling means to maintain a predetermined pressure in the vacuum chamber. The vacuum pressure in the operating vacuum chamber can be pre-arranged so as to provide a suction force by a pressure difference even when there is a shortage of electricity.

BACKGROUND OF THE INVENTION 
The present invention relates to a therapeutic suction device and 
particularly to one with a vacuum pressure controlling means to control 
the suction pressure of the device and an operating vacuum chamber kept at 
a controlled vacuum pressure to effect a suction by a pressure difference. 
There are different therapeutic suction devices, such as those for 
suctioning phlegm, a liquid from the stomach or the thorax of a patient 
body, etc. These suction devices typically include an electrically 
operated pump to effect suction, and are designed differently to operate 
at different suction pressures according to the kind of liquid to be 
suctioned from a patient body. For instance, to suction the liquid from 
the stomach the suction pressure must be maintained from 100-120 mmHg, and 
to suction viscous liquid the suction pressure must be maintained from 
300-400 mmHg. A suction device with a suitable suction pressure must be 
carefully chosen because if the pressure is too high it may harm the 
patient and if the pressure is too low it may render the suction 
ineffective. Furthermore, if there is a shortage of electricity during the 
suction operation, the operation can not continue and the suction device 
must be turned off so that the communication between the pump and the 
patient body is halted immediately. Therefore, the conventional devices 
are inconvenient. 
SUMMARY OF THE INVENTION 
An object of the invention is to provide a therapeutic suction device that 
can effect a suction of a liquid from a patient body with a predetermined 
suction pressure. 
Another object of the invention is to provide a therapeutic suction device 
including an operating vacuum chamber by which the device can operate even 
when there is a shortage of electricity. 
According to the present invention, a suction device comprises a vacuum 
chamber, means for creating a vacuum pressure in the chamber, including a 
pump connected to the vacuum chamber, a solenoid valve for interrupting 
the communication between the pump and the vacuum chamber, an electric 
power means for operating the vacuum pressure creating means, a control 
circuit means to control the power means, a first pressure controlling 
means for detecting the pressure in the vacuum chamber and for 
deenergizing the control circuit in response to a predetermined suction 
pressure of the vacuum chamber, a container means for receiving a liquid 
suctioned from a patient body, communicated with the vacuum chamber and 
having a liquid inlet means, and a valve means for opening and closing the 
liquid inlet means. 
In one aspect of the invention, the control circuit means includes a 
normally closed microswitch to be actuated by the pressure controlling 
means, and a relay in circuit with said microswitch, said motor and said 
solenoid valve means. 
In another aspect of the invention, the pressure controlling means includes 
a main pressure controlling bellow to be maintained at a first 
predetermined suction pressure therein, communicated with the vacuum 
chamber, the bellow having a fixed end and a movable end, means for 
actuating the microswitch of the control circuit when the first 
predetermined suction pressure is reached, having a stem with one end 
thereof connected to the movable end of the bellow, and an adjustment 
means to set the pressure of the bellow at the predetermined pressure. 
In further aspect of the invention, the container means includes a 
plurality of container units and the pressure controlling means further 
includes a plurality of sup-pressure controlling bellows each communicated 
with the main pressure controlling bellow to be maintained at a second 
predetermined suction pressure lower than the first predetermined 
pressure, and communicated with each of the container units. 
In still further aspect of the invention, the liquid inlet valve means 
includes a valve casing, having a rear end, a forward end and a passage 
extending from the rear end to the forward end, and an operating means 
having a valve plug means normally closing the passage and a push button 
to push the plug means to a position opening the passage. 
The present exemplary preferred embodiment will be described in detail with 
reference to the following drawings, in which:

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings, there is shown a therapeutic suction device 
which includes a vacuum chamber 2, a motor 14 and a pump 15 for creating a 
vacuum pressure in the chamber 2, and a control circuit 10 in connection 
with a power source (not shown) for controlling the motor 14. The control 
circuit 10 includes a normally closed microswitch 12 for opening the 
circuit 10 when the vacuum pressure in the chamber 2 reaches a 
predetermined pressure, a relay 11 in circuit with the microswitch 12, the 
motor 14 and a solenoid valve 13. The pump 15 is communicated with the 
chamber 2 through a conduit 16 and the solenoid valve 13 is disposed at a 
location of the conduit 16 for interrupting the communication between the 
pump 15 and the chamber 2. When the control circuit 10 is closed, the 
motor 14 operates the pump 15, creating a vacuum pressure in the chamber 
2. When the microswitch 12 is opened to deenergize the circuit 10 by means 
of a pressure controlling means 3, the operation of the motor 14 and pump 
15 stops and the solenoid valve 13 interrupts the communication between 
the pump 15 and the chamber 2. 
During the operation of the suction device, the pressure controlling means 
3 controls the microswitch 12 as well as the circuit 10 so as to maintain 
a predetermined vacuum pressure in the chamber 2. The vacuum pressure in 
the chamber 2 can be maintained even when there is a shortage of 
electricity by the interruption of the solenoid valve 13. 
The pressure controlling means 3 is connected to the chamber 2, and 
includes a main pressure controlling bellow 31 which has a fixed end 31a 
mounted on a support 33 and is connected to the conduit 21 through a 
manifold so as to be communicated with the bellow 31. The bellow 31 
further has a movable end 31b to which a stem 34 is connected. The stem 34 
is axially movable and has one end portion 32 extending into the bellow 31 
and the other end portion which is threaded and to which is attached an 
adjustment nut 36. A spring 35 is sleeved around the stem 34 to bias the 
movable end 31b toward to the fixed end 31a so as to set the movable end 
at a certain distance from the fixed end by adjusting the nut 36. When a 
vacuum pressure is created in the bellow 31 and in the vacuum chamber 2, 
the movable end 31b moves toward the fixed end and the nut 36 moves 
towards the microswitch 12. When the nut 36 actuates a lever 37 of the 
microswitch 12, the microswitch 12 is turned off. In this situation, the 
motor is stopped and the solenoid valve 13 is closed, interrupting the 
communication between the chamber 2 and the pump 15. A predetermined 
pressure is thereby maintained in the vacuum pressure chamber 2. The 
vacuum pressure in the chamber 2 is adjusted by the adjustment of the nut 
36. When the suction or vacuum pressure decreases due to the application 
of the suction device, the stem 34 will move away from the fixed end 31a 
and the nut 36 will move away from the lever 37 of the microswitch 12. 
Accordingly, the circuit 10 will be closed again and the pump will operate 
again. 
In order to connect the vacuum chamber 2 to two liquid flasks or more than 
two liquid flasks, the conduit 21 of the vacuum chamber 2 can be arranged 
with a manifold arrangement. As is shown in the drawings, the pressure 
controlling means 3 further includes two sup-pressure controlling bellows 
53 which are connected to the conduit 21 through manifolds 22. Each bellow 
53 has a fixed end through which each manifold 22 extends into the bellow 
53, and has the other end movable and connected to a movable stem 54. Each 
stem 54 has a head portion 51 extendng into the bellow 53 through the 
movable end 52. Opposite the head portion 51 is an adjustment nut 55 and a 
spring 56. By adjusting the nut 55, the pressure in the bellow 53 can be 
adjusted. When the vacuum pressure in the bellow 53 reaches a 
predetermined value, the movable end of the bellow 53 moves toward the 
fixed end, and the head portion 51 blocks up the opening of the manifold 
22, interrupting the communication between the bellow 53 and the vacuum 
chamber 2. The vacuum pressure maintained in each bellow 53 is lower than 
that in the bellow 31. 
Each bellow 53 is connected to a liquid flask 43 through a conduit 44. The 
liquid flask 43 is provided with an inlet conduit 69 which will be 
directed into a patient body. Between the liquid flask 43 and the bellow 
53 is provided a pressure gauge 42 and a valve 41. An inlet valve means 6 
is disposed at the inlet conduit 69 of each liquid flask 43. 
Each valve means 6 includes a valve casing 62 which has a passage 61 
extending from a forward end 61a and a rear end 61b of the casing 62. An 
operating rod 67 is inserted movably in the passage 61 and an operating 
knob 66 which is connected integrally with the operating rod 67 has a 
sleeve portion 66a sleeved slideably around the rear end 61b of the valve 
casing 62. A spring 64 is received in the rear end 61b and sleeved around 
the rear portion 68 of the operating rod 67. A conduit 70 is screwed to 
the valve casing 62 to communicate with the passage 61 and is directed to 
the liquid flask 43. The forward end 61a of the valve casing is connected 
to the conduit 69. At a front end of the operating rod 67 is a valve plug 
671 which normally blocks up the front end of the passage so that the 
conduits 69 and the conduit 70 are not intercommunicated. When in use, one 
may just push the operating knob 66 forward to effect the suction 
operation. 
When the liquid flask 43 is full, it can be replaced by a next flask by 
closing the valve 41 and detaching the liquid filled flask 43 from the 
suction device. 
While the above-described embodiment includes a main pressure controlling 
bellow 31 and two sup-pressure controlling bellows 53, the invention is 
not limited thereto. The suction device of the invention may include a 
single pressure controlling bellow or a main pressure controlling bellow 
with more than two suppressure controlling bellows. It can be appreciated 
that the vacuum pressure created in the chamber 2 provides a suction force 
even when there is a shortage of electricity. 
With the invention thus explained, it is apparent that various 
modifications and variations can be made without departing from the scope 
of the invention. It is therefore intended that the invention be limited 
as indicated in the appended claims.