U.S. patent number 3,756,271 [Application Number 05/165,103] was granted by the patent office on 1973-09-04 for apparatus for delivering a predetermined volume of fluid at regular intervals.
This patent grant is currently assigned to H. G. East Company Limited. Invention is credited to Maurice Frederick Freeman, Alan Walter Grogono.
United States Patent |
3,756,271 |
Grogono , et al. |
September 4, 1973 |
APPARATUS FOR DELIVERING A PREDETERMINED VOLUME OF FLUID AT REGULAR
INTERVALS
Abstract
Fluid delivery apparatus for intermittently delivering a
selected volume of fluid in which a resilient device is
compressible by pressure of the fluid in a pressure chamber, a
valve mounted on the resilient device being opened to deliver the
fluid when a predetermined degree of compression has been achieved
and being subsequently closed when the falling pressure in the
pressure chamber permits a predetermined expansion.
Inventors: |
Grogono; Alan Walter (London,
EN), Freeman; Maurice Frederick (Oxford,
EN) |
Assignee: |
H. G. East Company Limited
(Oxford, EN)
|
Family
ID: |
10380247 |
Appl.
No.: |
05/165,103 |
Filed: |
July 22, 1971 |
Foreign Application Priority Data
|
|
|
|
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Jul 23, 1970 [GB] |
|
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35,667/70 |
|
Current U.S.
Class: |
137/494;
128/205.24 |
Current CPC
Class: |
A61M
16/0081 (20140204); A61M 16/00 (20130101); A61M
16/0075 (20130101); Y10T 137/7781 (20150401) |
Current International
Class: |
A61M
16/00 (20060101); A62b 007/00 (); A61m
015/00 () |
Field of
Search: |
;128/145.5,145.6,145.7,145.8 ;137/494,503,510,503.36 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
648,191 |
|
Jan 1951 |
|
GB |
|
227,106 |
|
1968 |
|
SU |
|
Primary Examiner: Klinksiek; Henry T.
Assistant Examiner: Miller; Robert J.
Claims
We claim:
1. Fluid delivery apparatus including:
a pressure chamber;
means for introducing fluid under pressure into the chamber;
resilient means in the chamber compressible by the fluid as the
fluid pressure in the chamber increases;
a valve mounted on the resilient means and movable upon compression
of the resilient means within the chamber; and
means for actuating the valve after a predetermined movement
thereof to permit fluid to exhaust from the chamber.
2. Apparatus as claimed in claim 1, in which said valve comprises
two members mounted on the resilient means, said two members being
movable relative to each other and biased apart.
3. Apparatus as claimed in claim 2, in which said actuating means
includes at least one stop to limit movement of one of the valve
members in the chamber.
4. Apparatus as claimed in claim 3, in which said stop is
variable.
5. Apparatus as claimed in claim 4, in which said resilient means
comprises a bellows device, one end of which is fixed in the
chamber and the other end of which carries the valve members.
6. Apparatus as claimed in claim 5 in which said one of the valve
members is a valve disc and the other of said valve members is a
valve cup secured to said other end of the bellows device.
7. Apparatus as claimed in claim 6, comprising a fluid outlet line
from the chamber which communicates with the interior of the valve
cup and includes a further pressure opening non-return valve.
8. Apparatus as claimed in claim 7, in which the outlet line
branches, one branch including a flow control and serving as a line
to exhaust fluid under pressure from the chamber and the other
branch terminating in a valve which closes said other branch during
exhaust of fluid under pressure from the chamber via said one
branch, and which opens said other branch after exhaust of fluid
under pres-sure from the chamber is terminated.
9. Apparatus as claimed in claim 1 in which said chamber includes
means for evaporating water.
10. Apparatus as claimed in claim 8, wherein said other branch is
adapted to receive input fluid to the chamber when the valve
terminating said other branch is open.
11. Apparatus as claimed in claim 1, in which said resilient means
comprises a bellows device, one end of which is fixed in the
chamber and the other end of which carries the valve.
12. Apparatus as claimed in claim 11, in which said valve comprises
two members mounted on the resilient means, said two members being
movable relative to each other and biased apart, one of the valve
members being a valve disc and the other of said valve members
being a valve cup secured to said other end of the bellows
device.
13. Apparatus as claimed in claim 1, comprising a fluid outlet line
from the chamber which is operatively controlled by the valve, the
outlet line branching into two branches, one branch including a
flow control and serving as a line to exhaust fluid under pressure
from the chamber and the other branch terminating in a valve which
closes said other branch during exhaust of fluid under pressure
from the chamber via said one branch, and which opens said other
branch after exhaust of fluid under pressure from the chamber is
terminated.
Description
This invention relates to apparatus for providing an intermittent
flow of fluid, and is particularly useful in devices used for
administering artificial ventilation in which air, oxygen or other
suitable gas mixture intermittently inflates a patients lungs.
It is an object of the present invention to provide apparatus which
is simple and which intermittently delivers a fixed volume of
fluid.
SUMMARY OF THE INVENTION
The present invention is fluid delivery apparatus including a
pressure chamber, means for introducing fluid under pressure into
the chamber, resilient means in the chamber compressible by the
fluid, a valve operable upon compression of the resilient means and
means for actuating the valve after a pre-determined movement
thereof to permit fluid to exhaust from the chamber.
An embodiment of the present invention will now be described, by
way of example, with reference to the accompanying drawing, the
single FIGURE of which diagrammatically illustrates an artificial
ventilator for use with a human patient.
Referring now to the drawing, a ventilator for use with a human
patient who cannot, or who finds it difficult to, breathe for
himself comprises a pressure chamber 10 in which is mounted a
resilient bellows device 11 and a valve 12.
The chamber 10 is provided with a gas inlet 14 and is gas tight at
the pressures normally encountered in use.
The resilient bellows device 11 is sealed and at one end 17 is
fixed to a bracket 16 on the walls of the chamber 10. The other end
18 of the bellows device 11 is free to move in the chamber and
carries the valve 12.
The valve 12 includes two valve members, a valve cup 19 and a valve
disc 20. The valve cup 19 is mounted on the end 18 of the bellows
device 11 and moves with it. The interior of the valve cup 19
connects with an outlet line 21. The valve disc 20 is mounted by
radial springs 24 on brackets 25 extending from the end 18 of the
bellows device 11, the radial springs 24 providing a small bias of
the valve disc 20 away from the valve cup 19. A pin 26 extends from
the valve disc 20 on its side remote from the valve cup , passes
through holes 27 in a bracket 28 and a lever 29, and is provided
with collars 30 which are large enough to engage the edges of the
holes 27 and thus act as stops to limit movement of the pin 27 and
valve disc 20 towards the right and left respectively as seen in
the drawing. The lever 29 has a fixed pivot 32 at one end and at
its other end engages a cam 33 rotatable by a knurled control knob
34.
The outlet line 21 branches into two lines 35 and 36, one of which
35, is provided with a flow control valve 38 and the other of
which, 36, terminates in a bellows valve 39.
In use the gas inlet 14 is connected to a suitable supply of
pressurised gas, for example a pressure bottle, the line 35 is
connected to the patient as the inspiratory line and the expiratory
line 40 from the patient terminates at the bellows valve 39.
Assuming that initially the chamber 10 is not pressurised, the
bellows device 11 is expanded so that the valve cup 19 is in
engagement with the valve disc 20 whose movement to the right has
been restricted by engagement of a collar 30 with the bracket 28.
As the pressure in the chamber 10 builds up, the bellows device 11
is compressed and its end 18 moves to the left as seen in the
drawing. The valve disc 20 remains in engagement with the valve cup
19 as the pressure differential between the sides of the valve disc
20 maintaining such engagement is greater than the force exerted by
the radial springs 24 tending to part the valve disc and cup.
Compression of the bellows device 11 continues until engagement of
the lever 29 with a collar 30. No further movement then occurs
until the pressure in the chamber 10 has increased slightly and the
force due to the pressure differential between the faces of the end
18 of the bellows device over the annular area around the valve cup
19 has increased to compensate for the force on the valve disc that
has been taken up by the lever 29 and is no longer effective on the
bellows device. When the pressure has built up sufficiently the
valve springs open under the influence of the springs 24 and the
increased pressure on the inside of the valve cup 19. The gas in
the chamber passes to the outlet line 21 and thence through the
line 36 to the bellows valve 39, to close the expiratory line from
the patient, and, via the valve 38 to the patient to inflate the
patient's lungs.
Gas flowing from the outlet line 21 causes the pressure in the
chamber 10 to decrease causing a corresponding expansion of the
bellows device. As the end 18 of the bellows device moves to the
right it takes with it the brackets 25 and the valve disc 20 until
the collar 30 engages the bracket 28. The bellows device continues
to expand and closes the valve cup 19 against the stationary valve
disc 20.
The pressure on either side of the bellows valve 39 now equalises,
the valve 39 opens and the patient's lungs deflate. Meanwhile
pressure in the chamber 10 is increasing and, when the valve 12
reopens deflation is terminated and inflation of the patient's
lungs recommences.
It should be noted that the ventilator is essentially a constant
volume device opprating as it does on pressure differentials with a
constant volume, i.e., the pressure chamber. The volume passed in
each cycle can however be varied by adjustment of the knob 34 and
thereby of the cam 33 and the lever 29 thus effectively adjusting
the travel of the pin 26. It should also be noted that the
ventilator is extremely simple and is stable in both the open and
closed positions.
Modifications may be made to the embodiment described. It may be
desirable to ensure positive operation of the valve 12 by including
in the line 21 a pressure opening non-return valve 41. Also it may
be convenient to have access to the interior of the bellows to
permit pressurisation thereof during manufacture for calibration
purposes. Moreover the pressure chamber may be fitted with a
heating element to vapourise water in the chamber. This arrangement
permits humidification of gases leaving the chamber as well as
sterilisation of the apparatus by boiling.
The ventilator may be adapted so that its operation is initiated by
an external signal such as a change in pressure at the outlet
caused by attempts by the patient to breathe. This can be achieved
by rendering the stop involving the lever 29 inoperative, limiting
the gas pressure in the chamber, and providing a conventional lever
arrangement to change the pressure change, caused by a patient
attempting to breathe into a force sufficient to open the valve
12.
The invention has been described in relation to a ventilator but is
equally applicable in any system where intermittent supply of
specified volumes of fluid is desired.
* * * * *