Abstract:
A drip chamber ( 1 ) for body fluid and discharge kits, includes a hollow tubular external closure ( 2 ) with a connector ( 4,5,6 ) formed at a first end for an outward fluid-flow connection to an external circuit and a second open end ( 3 ) arranged opposite to the first end, and a monolithic filtering element ( 7 ), formed of a cylindrical filtering body ( 8 ) with a first end supported by the connector bottom ( 4 ), and of a plug ( 10 ) with an inward fluid flow tube ( 11 ) monolithically attached to a second end of the cylindrical filtering body ( 8 ) and hermetically attached to the second end ( 3 ) of the hollow tubular external closure ( 2 ).

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a drip chamber for transfusion, dialysis, infusion kits, and the like. 
     Several kinds of drip chamber are commercially known which are meant to be inserted along the circuit of single-use extracorporeal lines such as kits for transfusions, dialysis or the like in order to prevent the passage of any impurities contained in the fluids being conveyed. Conventional drip chambers are composed of a plurality of components, usually at least four, which are glued together so as to form a tubular external enclosure which contains a filtration mesh and is closed at its ends respectively by two plugs provided with a coupling for the tubes for the infeed and discharge of the body fluids and optionally for additional tubes for connection to other lines or instruments, such as for example an injection point or a pressure gauge. The fluid that arrives from the infeed tube passes through the filtration mesh before reaching the outlet. It has been ascertained that drip chambers of this type operate correctly, and considering that they are discarded after a single use, in mass production it is a primary goal to minimize the number of parts required to produce the end product and to simplify the assembly procedure and its complexity. 
     SUMMARY OF THE INVENTION 
     The aim of the present invention is to obviate the above drawbacks of prior art devices, i.e. to provide a drip chamber for transfusion, dialysis, infusion kits, and the like which can be assembled in a simple manner and uses the smallest possible number of parts. 
     Within the scope of this aim, an object of the present invention is to achieve the above aim with a drip chamber which is relatively easy to provide in practice, safe in use, effective in operation and relatively low in cost. 
     This aim, these objects and others are all achieved by the present drip chamber for transfusion, dialysis, infusion kits, and the like, characterized in that it comprises a tubular external enclosure in which a first end is closed by a connector provided with at least one tube for connection to the external circuit and a second end lies opposite said first end, said enclosure accommodating a filtering element which is composed of a substantially cylindrical filtering body which forms an interspace with said enclosure, said filtering body having an end which is internal to said enclosure and is closed by a bottom and an end which is rigidly coupled to a closure element which is inserted in said second end of said enclosure and is provided with a tube for connection to the external circuit, said body and said closure element being monolithic. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the present invention will become apparent from the following detailed description of preferred embodiments of a drip chamber for kits for transfusion, dialysis, infusions and the like according to the invention, illustrated only by way of example in the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of the chamber; 
     FIG. 2 is a longitudinal sectional view of the chamber of FIG. 1; 
     FIG. 3 is a sectional view of a first variation; 
     FIG. 4 is a sectional view of a second variation; 
     FIG. 5 is a sectional view of a third variation; 
     FIG. 6 is a sectional view of a fourth variation; 
     FIG. 7 is a sectional view of a fifth variation. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the above figures,  1  generally designates a drip chamber for kits for transfusion, dialysis and the like according to the invention. 
     The drip chamber  1  is composed of a tubular external enclosure  2  which is formed by molding a material such as plastics, so as to have an open end  3  and another end which is closed by a connector which comprises a bottom  4  from which two tubes  5  and  6  protrude, which are parallel to the axis of the enclosure, and are designed for connection to a tube which leads to the pressure gauge or to the injection point and respectively to a tube for the discharge of the blood or other medical liquid. 
     The numeral  7  designates a filtering element which is formed by a filtering cylinder  8  which is formed by a filtering mesh and whose diameter is slightly smaller than the diameter of the enclosure  2 , so that when it is inserted in said enclosure it defines an interspace  9  between the enclosure and the cylinder  8 . The end of the element  7 , arranged at the opening  3 , forms a plug  10  which is provided with an annular outer lip for abutment on the edge of the enclosure  2  and is centrally provided with a tube  11  which protrudes axially outward and connects the inside of the filtering cylinder  8  to the outside; the hermetic closure of the plug  10  in the enclosure  2  is achieved by gluing, welding or mechanical interlocking of the components. 
     The tube  11  is designed for coupling to the infeed tube for the blood or other medical liquid from the external circuit. 
     In order to use the chamber  1 , the connecting tubes can be constituted by cannula-type perforating tips adapted to perforate bottles and flasks with a rubber stopper or pouches containing blood or other medical liquids. 
     The opposite end of the element  7  rests on the bottom  4  and is provided with a collar  13  for centering the filtering element inserted on the edge of the bottom  4 . 
     A fundamental feature of the invention is the particular structure of the filtering element  7 , which allows to form the filtering cylinder  8 , the collar  13 , the plug  10  and the tube  11  monolithically by molding plastics. 
     The operation of this device is known: the blood (or other liquid) conveyed by the tube  11  enters the filtering cylinder  8 , flows from there into the interspace  9  and then exits through the tube  6 . Conveniently, the path of the fluid can be reversed without affecting in any way the function of the instrument. 
     The tube  5  is connected to a pressure gauge, which measures the blood pressure by measuring the pressure of the air that is present in the upper half of the filter, and a hydrophobic membrane  12  is inserted therein; said membrane is designed to prevent any rise of the blood along the tube  5  to the pressure gauge while allowing the passage of air and therefore the measurement of the pressure. 
     The drip chamber provided according to the invention is formed by just two parts and its assembly is extremely simple: it is in fact sufficient to glue, weld or interlock the centering collar  13  and the plug  10  to the external enclosure  2 . 
     In an alternative embodiment of the filter, shown in FIG. 3, the filtering element  7  is closed, on the side of the tubes  5  and  6 , by a bottom  14  which is inserted snugly in the end of the filtering cylinder  8 . A finger  15  protrudes axially from the region between the tubes  5  and  6  towards the inside of said enclosure and abuts in a central seat  16  formed in the bottom  14 , preventing it from leaving the cylinder  8  and allowing to center it inside the enclosure  2 . 
     A further embodiment of the invention, shown in FIG. 4, is constituted by an external enclosure  2  which contains a filtering cylinder, closed as in the preceding example by means of a bottom  17 , which in this case is glued to the mouth of the cylinder  8  and has a plurality of radial spacers which are adapted for centering by resting on the internal surface of the enclosure  2 . 
     In still another embodiment of the chamber  1  (see FIG.  5 ), the open end of the external enclosure  102  is located on the liquid discharge side instead of on the infeed side as in the preceding example. In this case, the filtering element  107  is composed of a plug  110  which is shaped so as to be able to close hermetically the opening  103  of the enclosure  102 . Two tubes  105  and  106  protrude outwards from the plug and are meant respectively for connection to the pressure gauge and to the liquid discharge tube; a finger  18  protrudes inwards from said plug and ends by forming a bottom  19  for closing the filtering cylinder  108 . The open end of the cylinder  108  forms a tubular portion  20  adapted to form a seal with the internal wall of the enclosure  2 , so as to force the liquid that enters through the tube  111  to pass through the filtering walls of the cylinder  108  in order to reach the interspace  9  and from there the discharge connector. The finger  18  can be folded and compressed so as to define a sort of leaf spring adapted to apply pressure toward the cylinder  108  in order to ensure the seal between said cylinder and the wall of the enclosure  102 . 
     Furthermore, in still another alternative solution, shown in FIG. 6, the cylinder  208  and the external enclosure  202  are provided monolithically. In this case, the seal between the bottom  204  of the enclosure  202  and the end of the cylinder is provided during molding, while the opposite end is provided with a tubular portion  21  adapted to hermetically engage the plug  22 , which closes the opening  203  and has a coupling  23  for connection to the infeed tube. 
     In a last embodiment proposed by way of example in FIG. 7, the filtering element is constituted, according to the known art, by a cylinder  24  in which the lateral walls are formed by a filtering mesh; said cylinder is closed at one end by a bottom  25  and is glued or inserted by pressing, at the other end, in a plug  26  for closing the open side of the external enclosure  2 . The plug  26  is axially provided with a tube  27  for connection to the fluid infeed tube. 
     It has thus been observed that the invention achieves the intended aim and object and that in particular it is formed with a minimal number of parts, two or three at the most), which can be manufactured easily and are simple to assemble. 
     The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may furthermore be replaced with other technically equivalent ones. In particular, the connectors for the discharge of the liquid can also be more than two and can comprise, for example, an injection point for adding substances to the filtered liquid. 
     In practice, the materials employed, as well as the shapes and the dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims.