Backflow check valve for use with IV administration sets

A backflow check valve includes male and female hubs sonically welded together with a flow control disc located within the check valve. The disc permits flow in one direction through the check valve, but prevents flow in the other direction through the check valve.

BACKGROUND OF THE INVENTION 
The present invention relates in general to IV administration sets, and, 
more particularly, to a backflow check valve for use in IV administration 
sets. 
There are several devices presently available which concern IV 
administration sets. An example of such devices is shown in U.S. Pat. No. 
3,886,937. 
However, these known devices usually include a check valve which is 
expensive and not entirely reliable. These problems arise due to the 
complex nature of any backflow preventing element used in the check valve. 
Such backflow preventing elements used in the prior art often include 
legs, spacers, or the like located on the surfaces of the backflow 
preventing element. Because of these extra elements on the backflow 
preventing element, exotic manufacturing techniques are often required, 
thereby increasing the overall cost of the check valve, while reducing the 
overall reliability of that check valve. 
SUMMARY OF THE INVENTION 
The device embodying the teachings of the present invention includes a 
female hub and a male hub sonically welded together. Flow passages are 
defined through the hubs to be positioned with respect to each other so 
that fluid can flow through the device when desired. 
A flow control disc is located between the two hubs to permit flow in one 
direction, but to prevent flow in the other direction, i.e., backflow. The 
disc is circular in peripheral outline and has unobstructed flat surfaces 
thereon. A disc abutment means is mounted on the male hub to prevent the 
disc from becoming dislodged and moving into the male hub flow passage. 
Flow bypass paths are defined in the male hub element so that flow can 
bypass the flow control disc when fluid communication between the male and 
female hub flow passages is desired. 
The backflow check valve essentially prevents flow from a primary set until 
a secondary bottle is emptied when used in conjunction with a Y-injection 
site. 
The control valve of the present invention is easily manufactured by 
techniques such as simple die cutting, stamping or the like. The check 
valve disc is preferably rubber, or other substance having a natural 
resiliency. The natural resiliency produces a positive backflow 
prevention, thereby further increasing the reliability of the check valve. 
The simple form of the backflow preventing element used in this device 
reduces the overall cost of the check valve considerably from the cost of 
prior art devices. For example, prior art devices include backflow 
preventing elements costing two to five times as much as the simple disc 
included in the presently disclosed check valve. 
OBJECTS OF THE INVENTION 
It is a main object of the present invention to provide a backflow 
preventing check valve for use in an IV administration set. 
It is another object of the present invention to provide a backflow check 
valve for use in an IV administration set which is used in conjunction 
with a Y-injection site means. 
It is yet another object of the present invention to provide a backflow 
check valve for use in an IV administration set which is sonically welded 
together. 
These together with other objects and advantages which will become 
subsequently apparent reside in the details of construction and operation 
as more fully hereinafter described and claimed, reference being had to 
the accompanying drawings forming part hereof, wherein like reference 
numerals refer to like parts throughout.

DETAILED DESCRIPTION OF THE INVENTION 
Shown in FIG. 1 is a Y-injection site means 10 inserted between tubing 12 
and tubing 14 with a backflow preventing check valve 20 connecting tubing 
12 to the injection site 10. 
The backflow check valve is the subject of the present disclosure, and is 
best shown in FIG. 2 to include a female hub 22 and a male hub 24. The 
hubs 22 and 24 are connected together by a sonic weld 26. 
The female hub includes a cylindrical trunk section 30 and a cylindrical 
coupling section 32 having an outer diameter larger than the outer 
diameter of the trunk section to define a shoulder 34 at the intersection 
of these two sections. A bore 36 is defined longitudinally of the hub 22 
to define a female luer taper 38. The coupling section 32 has a 
cylindrical bore 40 defined longitudinally thereof which has an inner 
diameter larger than the inner diameter of the bore 36 located adjacent 
the bore 40. A circular shoulder 42 is defined at the discontinuity formed 
at the intersection of the two bores 36 and 40, and a port 46 is defined 
centrally through the shoulder 42 to fluidly connect the two bores 36 and 
40 together. 
A circular flow control disc 50 rests on upper surface 52 of the shoulder 
42 and has an outer diameter slightly smaller than the outer diameter of 
the bore 40 to define an annular gap 54 between these two elements. 
Preferably, the disc 50 is rubber having a specific gravity of about 0.98. 
A specific gravity of less than one permits the dic to float upward into 
the FIG. 2 occluding position, thereby aiding the closing of the check 
valve when flow is in the wrong direction. 
The disc 50 has smooth, unobstructed first and second surfaces 56 and 58, 
respectively, and is essentially circular in peripheral outline. Such a 
shape permits easy manufacture as by stamping, die cutting, or the like, 
thereby providing a check valve which is far less costly than prior art 
devices which include flow blocking elements having legs, or other such 
elements on the surfaces thereof. Such prior art blocking elements having 
legs, and the like, are difficult to manufacture and hence expensive and 
not as reliable as the disc 50. 
The male hub 24 includes a cylindrical trunk section 60 and a cylindrical 
coupling section 62. A sealing shoulder 64 surrounds the hub adjacent the 
intersection of the trunk and coupling sections 60 and 62. The sealing 
shoulder is sonically welded to the female hub coupling section to form 
the sonic seal 26. 
A bore 70 is defined longitudinally of the trunk section 60 and is tapered 
to form a male luer taper 72. A cylindrical bore 76 is defined 
longitudinally of the coupling section 62, and has an inner diameter 
larger than the inner diameter of that part of the luer taper 72 located 
adjacent the coupling section to define a shoulder 78 at the intersection 
of the two bores 70 and 76. A port 80 is defined through the shoulder 78 
to fluidly couple the bores 70 and 76 together. 
A cylindrical skirt portion 84 is located on the lowermost portion of the 
male hub 24, and a tapered portion 86 is located adjacent outer rim 90 of 
the hub 24. 
As shown in FIG. 2, the outer diameter of the coupling section 62 is less 
than the inner diameter of the coupling section bore 40 to define an 
annular gap 92 between those two coupling sections. The tubing 12 is 
attached to the female hub 22, and a leg L of the Y-injection site 10 is 
coupled to the male hub 24. 
A plurality of ribs 100 are defined on the coupling section skirt portion 
84 to extend longitudinally of the male hub 24. As best shown in FIG. 3, 
the ribs are spaced apart circumferentially about the bore 76, and define 
flow passages 100 therebetween. 
A disc seating member 126 is attached to the male hub and extends across 
the male hub flow passage and is sized to seat the disc thereon. The 
seating member 126 encloses an open area 124 therein. The seating member 
has a disc abutment surface 130 thereon. The surface 130 contacts first 
surface 56 of the disc 50 when fluid flows through the check valve in the 
direction of arrow F in FIG. 2 with sufficient force to move the disc from 
the occluding position shown therefor in FIG. 2 into abutting contact with 
the male hub. The disc abuts seating member 120 and is thus prevented from 
being forced into the bore 76 by the fluid passing from the female hub 
into the male hub in the flow direction F. When the disc abuts the male 
hub, fluid flows through the flow passages 100 to bypass the disc. 
However, when the fluid flow is in the direction opposite to the arrow F, 
the disc 50 abuts the shoulder 42 and occludes the port 46 and the bore 36 
to prevent backflow of fluid from the male hub into the bore 36 and hence 
into the tubing 12 via the valve 20. The FIG. 2 position is thus a closed 
position for the check valve 20, however, in an IV application, the valve 
is normally open. 
When fluid flow is in the direction indicated by the arrow F, the disc 50 
is moved against the male hub and the seating member 120. Fluid flows from 
port 46 longitudinally of the coupling section 32, then radially of that 
section when in contact with the disc second surface 58, then 
longitudinally of the coupling through the gap 54, then generally radially 
of the disc and coupling along the first surface 56 of the disc through 
bypass means 100. The fluid moves through open area 124 of the seating 
member 120, then moves longitudinally of the male hub through the port 80 
and into the leg L. 
As this invention may be embodied in several forms without departing from 
the spirit or essential characteristics thereof, the present embodiment 
is, therefore, illustrative and not restrictive, since the scope of the 
invention is defined by the appended claims rather than by the description 
preceding them, and all changes that fall within the metes and bounds of 
the claims or that form their functional as well as conjointly cooperative 
equivalents are, therefore, intended to be embraced by those claims.