Enclosure for a bottom draining container

A valve assembly and a bottom-draining container having the valve assembly. The valve assembly comprising a first body member, a guide member supported by the first body member so that the guide member will extend upward into the container, and a float mounted for movement along the guide member, the float being buoyant in a liquid to be drained from the container, the float having a mating surface for engaging a second mating surface on the valve assembly when the float is in the unsensed position, the mating surface of the float having a configuration for minimizing sticking of the float with respect to the valve assembly.

FIELD OF THE INVENTION 
The invention relates to containers for dispensing liquids. More in 
particular, the invention concerns containers with a bottom opening and 
techniques for detecting a low liquid level in such containers. 
BACKGROUND OF THE INVENTION 
Commonly assigned, published European Patent Application No. 0 675 072 A1 
discloses a valve assemblage useful for dispensing liquids from a 
collapsible container or a rigid, vented container. At the bottom of the 
container, a first valve is installed in the spout of the container, the 
first valve assembly including a moveable, spring-biased piston which 
normally prevents flow of liquid from the container. An associated 
apparatus, such as a photographic processor into which the liquid is to be 
dispensed, includes a second valve assembly having a probe member which 
engages the piston of the first valve assembly to move the piston to a 
position which permits flow. As the first valve assembly is opened by the 
probe member, the second valve assembly also opens, thus establishing a 
flow path for liquid from the container into the associated apparatus. 
As the associated apparatus operates, the liquid drains from the container. 
It would be desirable to provide a simple means for detecting and 
signaling a low liquid level within the container to enable an operator of 
the associated apparatus to replace the container in a timely fashion. 
Various systems are known for detecting liquid level in a vessel, such as 
those shown in U.S. Pat. Nos. 4,014,010 and 4,714,176. In copending U.S. 
patent application Ser. No. 08/671,459 entitled "Apparatus for Detecting 
Low Liquid in Bottom Draining Container", filed Jun. 27, 1996, there is 
disclosed a system for detecting low liquid level in a bottom draining 
container. In this copending application a float is used in combination 
with a beam of radiation to detect low level in the container in response 
to the position of the float. While the product works very well, a problem 
has been found in that occasionally the float may stick in position and 
thereby prevent proper operation of the detection system. In particular, 
surface tension between the engaging surface and the stop in combination 
with the surrounding liquid provides a surface tension such that 
occasionally the float will stick and cause misreadings. 
Applicants have solved the problem of the float sticking by providing an 
improved float member for use in the valve assembly associated with the 
container. 
SUMMARY OF THE INVENTION 
In accordance with one aspect of the present invention there is provided a 
valve assembly for a bottom-draining container. The valve assembly 
comprising a first body member, a guide member supported by the first body 
member so that the guide member will extend upward into the container, and 
a float mounted for movement along the guide member, the float being 
buoyant in a liquid to be drained from the container, the float having a 
mating surface for engaging a second mating surface on the valve assembly 
when the float is in the unsensed position, the mating surface of the 
float having a configuration for minimizing sticking of the float with 
respect to the valve assembly. 
In another aspect of the present invention there is provided a bottom 
draining container, comprising a spout extending from the container, the 
spout having a central bore through which liquid can drain from the bottom 
of the container, at least one guide member positioned in the spout, and a 
float mounted for movement in the spout along the guide member, the float 
being buoyant in a liquid to be drained from the container, the float 
having a first mating surface for engaging a stop when the float is in the 
unsensed position, the engaging surface having a configuration for 
minimizing sticking of the float with respect to the closure. 
In still another aspect of the present invention there is provided a valve 
assembly for a bottom-draining container. The valve assembly includes a 
first body member, a guide member supported by the first body member so 
that the guide member will extend upward into an associated container; and 
a float mounted for movement along the guide member, the float being 
buoyant in a liquid to be drained from the container and having an mating 
surface for mating a second mating surface on the body, the first or 
second mating surface having a configuration for minimizing sticking of 
the float. 
In yet another aspect of the present invention there is provided a bottom 
draining container, comprising a spout extending from the container, the 
spout having a central bore through which liquid can drain from the bottom 
of the container, a guide member positioned within the spout, and a float 
mounted from movement in the spout along the guide member, the float being 
buoyant in a liquid to be drained from the container, the float having an 
mating surface for engaging a second mating surface when the float is in 
the unsensed position, the first mating or second mating surface having a 
configuration for minimizing sticking of the float with respect to the 
body.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIGS. 1-3, those skilled in the art will understand a first 
embodiment of an apparatus 10 for detecting low liquid level in accordance 
with the invention. A container 12, shown only fragmentarily, may be 
collapsible or rigid and vented. In a suitable opening through the bottom 
of container 12, a spout 14 is mounted to extend outwardly of the 
container. A flange 16 extends radially outward from the spout 14 and is 
sealed to container 12 in any convenient way, such as by heat sealing. A 
central bore 18 extends through the spout 14 to facilitate draining of 
liquid from the container. At a lower end of bore 18, a radially inward 
and circumferentially extended flange 20 engages a combined valve body 22 
of valve assembly 21. A circumferential groove in body 22 tightly receives 
flange 20 to provide a seal. Extended upwardly from body 22 is an 
integrally molded valve cylinder 26 within which a hollow valve piston 28 
is mounted for sliding movement. A spring 30 is captured between cylinder 
26 and piston 28 to bias the piston 28 to the illustrated, closed position 
where a radially outwardly extended shoulder 32 on the piston engages a 
radially inwardly extended shoulder 34 on cylinder 26. A plurality of 
radial ports 36 extend through cylinder 26 near its lower end. In 
operation of the valve assembly 21 of FIG. 1, the container is lowered 
onto a mating probe of an associated valve assembly in an apparatus 80 
(see FIG. 8). A probe 82 (shown in FIG. 8) engages piston 28 and causes it 
to move upwardly within cylinder 26 against the force of spring 30. 
Eventually, ports 36 are opened as the piston moves upwardly, thereby 
permitting flow of liquid downwardly from container 12 to the associated 
apparatus. 
The invention provides means for detecting when the level of liquid reaches 
about the middle of spout 14. At least one annular float 38, made to be 
buoyant in the liquid flowing from the container, is mounted for sliding 
movement on an exterior surface of cylinder 26, which thus acts as a guide 
member for the float 38. A radially outwardly extended stop 40 is provided 
at or near an upper end of cylinder 26 to limit the upward movement of the 
float 38. Although float 38 moves on a guide member and has the advantage 
of capturing the float 38 within the spout 14, the float 38 may also 
comprise one or more spherical bodies placed in the container at the time 
of filling with liquid. In that instance, the float 38 would simply roll 
and settle into the spout 14 as the liquid level drops, making the guide 
member unnecessary, or the float 38 could be confined in the spout 14 by 
any suitable means which would not interfere with flow of liquid from the 
spout 14. 
Outside of spout 14, typically in the associated apparatus 80, a radiation 
source 42 is provided which produces a beam of radiation to which the 
materials of spout 14, cylinder 26 and piston 28 are translucent and to 
which the material of float 38 is opaque. The beam 47 of radiation is 
directed across a chord, preferably a diameter, of spout 14 so that the 
float 38 will intersect the beam 47 as the float 38 falls within the spout 
when the liquid has drained to that level. Opposite to source 42, a 
radiation detector 44 is provided. An alarm circuit 46, which may be 
comprised in a controller for the associated apparatus, is operatively 
connected to source 42 and detector 44. Those skilled in the art will 
appreciate that source 42 may be a conventional combined emitter and 
detector, in which case float 38 would be reflective of the beam and 
separate detector 44 would be unnecessary, without departing from the 
scope of the invention. Because the liquid level is detected in spout 14, 
only a small percentage of the liquid originally in the container will 
remain when detector 44 is actuated. This is important since many 
governmental units have issued environmental regulations which require 
that less than about 3%, typically, of a potentially hazardous liquid 
remain in the container at the time of disposal. 
When the liquid level is above spout 14, float 38 will rise to its maximum 
height against stop 40. The beam from source 42 will pass through the 
translucent materials of spout 14, cylinder 26 and piston 28 to detector 
44. As the liquid level drops into the spout, the float of opaque material 
will settle downward, eventually interrupting the beam of radiation and 
causing detector 44 and alarm circuit 46 to alert the operator of the 
associated equipment. For a source which produces light having wavelengths 
in the infrared spectrum, a suitable translucent material is low density 
polyethylene plastic, and a suitable opaque material is carbon-filled high 
density polyethylene plastic. Those skilled in the art will appreciate, 
however, that other materials and radiation spectrums may be selected 
without departing from the scope of our invention. 
As illustrated in FIGS. 1-3, the float 38 has an upper annular engaging 
surface 39 and a lower engaging annular surface 41. The upper annular 
mating surface 39 is designed to mate with (a substantially smooth) 
annular surface 43 of stop 40 and lower annular surface 41 is designed to 
mate with annular surface 45 of body 22. The annular mating surface 39 
and/or 43 is designed so as to minimize surface contact therebetween such 
that the float 38 will freely move up and down with respect to the body 
22. 
Referring to FIG. 3, there is illustrated float 38 by itself greatly 
enlarged. In the particular embodiment illustrated, annular mating surface 
39 has a saw-tooth-type pattern such that a plurality of edges 49 are 
provided which provide substantial edge contact with the mating surface 43 
of stop 40 and surface 45. Preferably, as illustrated in the embodiment of 
FIG. 2, the float 38 is symmetrical such that the annular mating surface 
41 is similarly constructed in the same manner as annular mating surface 
39. This helps minimize any potential problem associated with assembly of 
the valve assembly 21 and possibly improve ease of manufacturing of the 
float 38. However, if desired, the annular mating surface 41 may take any 
other shape of configuration and/or even be smooth if so desired. It is 
also to be understood that instead of modifying surface 39, mating surface 
43 may be modified to provide edge contact so that the float will not 
stick thereto. It is only necessary that one of mating surfaces 39,43 be 
constructed such that a minimal amount of surface area is provided so as 
to prevent sticking between the two surfaces. It is easier and more 
economical to provide the edge contact on float 38. It is to be understood 
the annular mating surfaces 39, 41, 43 and 45 may take a variety of other 
shapes and configurations in the scope of the present invention. FIGS. 4 
and 5 illustrate a modified float 38 made in accordance with the present 
invention. In this embodiment, surfaces 39 and 41 have a generally 
rectangular saw-tooth configuration. The flat sections 51 are small enough 
that sticking of the float will not occur. 
As illustrated in FIG. 1, the source 42 of radiation and detector 44 are 
positioned such that they are closely adjacent to the mating surface 45. 
In such cases it is important that the shape of the annular mating surface 
41 be such that a sufficient area of float 38 is provided to provide the 
appropriate signal to acknowledge when the float 38 is in the closed 
position as illustrated in FIG. 1. The annular mating surface is designed 
so a sufficient amount of area of the teeth of surface 41 is presented for 
either reflecting or stopping the beam of radiation so as to provide the 
appropriate signal. In this regard, the size, pattern and/or shape of 
teeth of the saw-tooth configuration of surface 41 are designed such that 
the beam of radiation being emitted from source 42 will either be 
reflected off the side of the float closed to the source, or on the other 
side of the float directly across the source 42 and thereby prevent the 
beam from passing through both sides of the float 38 when the float 38 is 
in the sensed position. 
It is to be understood that valve assembly 21 may be provided in various 
other type configurations such as illustrated in FIGS. 6 and 7. In 
particular FIG. 6 shows a second embodiment of the valve assembly 21, and 
container 12 includes an integral spout or neck 48, which accepts a 
screw-on closure 50 in the familiar manner. A central drain conduit 52 
extends from closure 50 and includes a conventional hose fitting 54 for 
attachment to a delivery hose, not shown, in the associated apparatus. 
Extended upwardly from closure 50 around an entrance to conduit 52 are a 
plurality of guide members 56 which may be molded integrally with the 
closure. The guide members are separated by slots 58, only one of which is 
visible in the section view of FIG. 6. Float 38 is mounted around the 
guide members and its upward movement is limited by radial stops 40 at or 
near upper ends of the guide members. The second embodiment operates in 
the same manner as the first. 
FIG. 7 shows a third embodiment of the invention. Rather than drain conduit 
52, closure 50 includes a central frangible portion 60 which can be broken 
by a sharp probe or cannula in the associated apparatus, in the familiar 
manner. Rather than a frangible portion, a pierceable septum may be use. 
Extended upwardly from closure 50 around portion 60 are a plurality of 
guide members 62 which may be molded integrally with the closure. The 
guide members are separated by slots 64, only one of which is visible in 
the section view of FIG. 3. The third embodiment operates in the same 
manner as the first and second. 
Referring to FIG. 8, there is illustrated a photographic apparatus 80 for 
developing of an exposed undeveloped photosensitive material, for example, 
film and/or paper. In a particular embodiment illustrated, photographic 
apparatus 80 comprises a minilab, however, the present invention is not 
limited to such. The apparatus 80 includes a plurality of probes 82, each 
designed to mate with an associated valve assembly 21. In the embodiment 
illustrated, four probes 82 are provided, however, any desired or required 
number may be provided. An appropriate mechanism 84 is provided for 
holding of a cassette 150 containing a plurality of containers 12, such as 
illustrated FIG. 8, in the inverted position such that when the cassette 
150 is lowered, the valve assemblies 21 of each container 12 in cassette 
150 will engage an associated probe 42 provided on apparatus 80. The 
cassette 150 may be manually lowered or may be lowered through the use of 
a powered mechanical system, not shown. 
When the valve assemblies 21 and probes 82 are urged toward each other in a 
mating relationship, an open fluid flow path is formed allowing liquid to 
flow from container 12 to apparatus 80. 
To disengage valve assemblies 21 from probes 82, they are urged away from 
each other to stop flow therebetween. 
The present invention provides an improved closure while the float moves 
freely between the unsensed and sensed positions and thus avoids the 
problem of the float sticking. In addition, the present invention is 
designed such that the float is of appropriate shape and weight so that it 
is sensed by the radiation such that an appropriate signal may be provided 
for indicating of low level liquid in the container. 
It is to be understood that various other changes and modifications may be 
made without departing from the scope of the present invention, the 
present invention being defined by the following claims. 
TS LIST 
10 Apparatus 
12 Container 
14 Spout 
16 Flange 
18 Central bore 
20 Flange 
21 Assembly 
22 Valve body 
26 Valve cylinder 
28 Valve piston 
30 Spring 
32 Outwardly extended shoulder 
34 Inwardly extended shoulder 
36 Ports 
38 Annular float 
39 Upper annular surface 
40 Stop 
41 Lower annular mating surface 
42 Radiation source 
43 Annular surface 
44 Radiation detector 
45 Annular surface 
46 Alarm circuit 
47 Beam 
48 Spout or neck 
49 Edges 
50 Closure 
51 Flat section 
52 Conduit 
54 Hose fitting 
56 Guide members 
58 Slots 
60 Frangible portion 
62 Guide members 
64 Slots 
80 Photographic apparatus 
82 Probe 
84 Mechanism 
150 Cassette