Dual valve liquid transfer tube

A liquid transfer device, which may be used as a drinking tube assembly to stablish fluid communication between the interior of a canteen and the interior of a protective mask, defines a pair of parallel fluid flow paths which respectively include opposite directly check valves. The parallel flow paths merge at the opposite ends of the assembly to form common flow paths which may be caused to respectively communicate with a suction tube and liquid storage container.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to the transfer of liquid into or out of a 
closed container and particularly to facilitating the withdrawal of 
potable liquid from a canteen by an individual wearing a protective mask 
which isolates the individual's breathing passages from the ambient 
atmosphere. More specifically, this invention is directed to a tube 
arrangement defining a pair of parallel flow paths which respectively 
include oppositely directed check valves and especially to a drinking tube 
assembly which facilitates the employment of a closed canteen by an 
individual wearing a protective face mask. Accordingly, the general 
objects of the present invention are to provide novel and improved methods 
and apparatus of such character. 
2. Description of the Prior Art 
While not limited thereto in its utility, the present invention is 
particularly well suited for use in establishing liquid flow communication 
between a protective respiratory mask and a canteen. 
There may, of course, be occasions where it is necessary to allow an 
individual wearing a protective mask to drink from a canteen or other 
closed liquid storage container. In the past, communication between the 
interior of the mask and canteen has been established by means of a single 
tube. The single tube drinking system has a number of inherent 
disadvantages. Firstly, the canteen must be raised at least to the level 
of the mask in order to obtain liquid flow. Also, with the single tube 
system, as liquid is withdrawn from the canteen a vacuum is created 
therein. The vacuum, in turn, limits the amount of liquid which can be 
withdrawn. Thus, for each swallow, the user must expend the effort of 
sucking liquid through the tube and, subsequent to drinking, must blow 
back into the canteen to pressurize the canteen, thus allowing more fluid 
to exit. 
A further disadvantage of the prior single tube system is that the canteen 
cannot be completely filled with the cap on, as may be necessary to 
prevent contamination, because a positive pressure will build up inside 
the canteen thus limiting the amount of liquid which can be delivered 
thereto. 
SUMMARY OF THE INVENTION 
The present invention overcomes the above-briefly discussed and other 
deficiencies and disadvantages of the prior art by providing a technique 
for withdrawing liquid from, and if desired also delivering liquid to, a 
closed vessel such as a canteen and a tube assembly for use in the 
practice of such technique. A drinking tube assembly in accordance with 
the invention defines a pair of parallel flow paths which are each 
provided with at least a first check valve, the check valves in the two 
flow paths operating in opposite directions. The parallel flow paths merge 
at the opposite ends of the tube assembly to form common flow paths which 
respectively may be caused to communicate with the interior of a liquid 
storage container and a suction, i.e., a drinking, tube or the like. If 
deemed necessary or desirable, one or both of the common flow path 
defining ends of the tube assembly may be provided with quick disconnect 
type fittings which cooperate with complementary fittings on the storage 
container and/or a protective mask.

DESCRIPTION OF THE DISCLOSED EMBODIMENT 
As indicated above, while not limited thereto in its utility, the present 
invention is particularly well suited to facilitate the drinking of liquid 
stored in a container such as a canteen, indicated at 10, by military 
personnel using a protective mask, for example a mask as described in 
military specification MIL-M-51282, Mask, Chemical, Biological, Field, 
which is indicated at 12. A preferred embodiment of the drinking tube 
assembly is indicated generally at 14 and comprises flexible tube means 
which define a pair of parallel conduits or flow paths 16 and 18. The 
structure of the tube assembly 14 is shown schematically in the drawing 
and the parallel flow paths 16, 18 may, as represented in FIG. 2 for 
example, be defined by adhesively bonding a pair of plastic tubes together 
and thereafter inserting the two tubes into a single outer tube 19 which 
functions as a sheath. In this case, the outer tube will, in some suitable 
manner, be bonded to the parallel inner tubes such that fluid is precluded 
from flowing between the inner and outer tubes. 
At the opposite ends of the tube assembly 14, i.e., between the ends of the 
parallel flow paths 16 and 18 and the ends of the tube assembly, the tube 
assembly defines single, i.e., common, flow paths 20 and 22. The flow 
paths 20 and 22 are, in the manner to be described below, in fluid flow 
communication with the parallel flow paths 16 and 18. 
The single flow path 20 terminates at a mouthpiece or suction tube 24 which 
extends from a cap 26. Suction tube 24 will form an extension of tube 
assembly 14 and will typically extend into the interior of the mask 12 
when the assembly is in use. Depending on construction, the suction tube 
24 may be integral with the tubular member which defines flow path 20 or 
may be a separate member. If the tubular member passes through cap 26, the 
exterior of the tube assembly is sealed to cap 26. The cap 26 mechanically 
engages the mask 12 in any suitable manner to capture the suction tube 24 
in a position where it may be employed for drinking purposes. 
The opposite end of the tube assembly 14, i.e., the end which defines the 
common flow path 22, may extend through and be sealed to a cap 28. Cap 28 
has a rotatable portion which mates with the threaded neck of the canteen 
10. With the cap 28 connected to the canteen 10, the free open end of the 
flow path 22 defining portion of the tube assembly 14 will extend into the 
canteen. 
The parallel flow paths 16 and 18 are provided with oppositely acting check 
valves. The check valves are preferably located adjacent the ends of the 
parallel flow paths which are in proximity to common flow path 22 and at 
the same level. As another alternative, a single check valve may be 
located at the upstream end of each of the flow paths 16 and 18. In the 
disclosed embodiment, the tube assembly 14 is provided with a pair of 
lower check valves, indicated generally at 30, and a pair of upper check 
valves, indicated generally at 32. As shown in FIG. 2, which is an 
enlarged cross-sectional view of the upper pair of check valves 32, the 
valves may be defined by cooperating flaps of the resilient material from 
which the tube assembly is fabricated. Pressure responsive flap-type 
valves of this type are well known in the art and are widely used in 
various types of pneumatic apparatus. 
If deemed necessary or desirable, quick disconnect couplings may be 
integrated with the tube assembly 14 at one or both ends thereof in the 
regions of the common flow paths. An example of such a quick disconnect 
coupling has been indicated schematically at 34. Coupling 34 will 
cooperate with a valve member inside the cap 26. In this arrangement, the 
cap 26 may remain permanently affixed to the mask 12 and the tube assembly 
simply plugged into the cap when the wearer wishes to drink. A similar 
quick disconnect coupling 36 may be employed at the opposite end of tube 
assembly 14 so as to cooperate with a valve assembly in the cap 28 which 
then could remain on the canteen 10. 
In use, the opposite ends of the tube assembly 14 are respectively coupled, 
either using caps 26, 28 which form a part thereof or employing quick 
disconnect fittings, to the mask 12 and canteen 10. The canteen is then 
held at an angle which permits the liquid inside to exit the cap. However, 
the canteen does not have to be held at the height of the mask, i.e., the 
end of the tube assembly 14 or the extension thereof defined by a tube 
which is integral with a cap 28 need only be submerged. The user then 
blows air into the canteen. This is accomplished by exhaling into the 
mouthpiece 24 inside of the mask. The exhaled air travels through the 
mouthpiece and down the tube assembly, passing through the one-way 
valve(s) in the flow path 18. After exhaling into the canteen, the user 
sucks on the mouthpiece 24 to draw water up from the canteen via the flow 
path 16 and the one-way valve(s) associated therewith. After each drink 
from the canteen, the user again exhales into the mouthpiece to pressurize 
the canteen for the next drink. The one-way valve(s) in the flow path 16 
prevent most of the liquid which has been drawn up into the tube assembly 
14 from returning to the canteen 10 even when air is being blow into the 
canteen, i.e., only the small amount of liquid in the common flow paths 20 
and 22 and the couplings will return to the canteen with the air. 
Accordingly, when compared to the prior art, the amount of effort required 
to get a drink is decreased because fluid does not have to be sucked all 
the way from the canteen to the mask more than once during each drinking 
cycle. 
The employment of a quick disconnect coupling at the canteen end of the 
tube assembly 14 permits the canteen 10 to be completely filled while the 
cap 28 is on tight and thereby ensures against contamination of water 
transferred to the canteen from a larger sealed reservoir. Thus, liquid 
delivered to the mask end of the tube assembly 14, via the quick 
disconnect coupling 34 for example, can flow through the one-way valve(s) 
in flow path 18 and into the canteen while air displaced by the inflowing 
liquid, rather than being trapped and pressurized, can escape via the flow 
path 16 and the one-way valve(s) incorporated therein. 
It is also to be noted that, when the present invention is used in a cold 
environment, the user can suck the tube assembly 14 dry after the canteen 
has been returned to a position similar to that shown in the drawing, 
presuming that the end of the tube assembly is at that time above the 
level of the liquid in the canteen. This will prevent the tube assembly, 
and the caps and quick disconnect fittings if a part thereof, from 
freezing. 
While a preferred embodiment has been shown and described, various 
modifications and substitutions may be made thereto without departing from 
the spirit and scope of the invention. Accordingly, it is to be understood 
that the present invention has been described by way of illustration and 
not limitation.