Special receptacle or package – Including ancillary article contacting medium – For tool or appliance
Reexamination Certificate
1998-06-30
2001-11-13
Weiss, John G. (Department: 3761)
Special receptacle or package
Including ancillary article contacting medium
For tool or appliance
C206S366000, C604S110000, C204S275100
Reexamination Certificate
active
06315113
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to chemical processes for disposing of medical and surgical sharps, such as hypodermic syringe needles, lancets, scalpels and the like. It relates further to means for applying the process to syringe needles after use. It relates still further to disposal boxes for applying the chemical disposal process to used and contaminated medical sharps.
BACKGROUND OF THE INVENTION
During the routine use of medical hypodermic syringes millions of times per day in the United States an abnormally high number of accidental needle sticks and injuries from needles occur. These small wounds to medical personnel and others are often contaminated with blood residue which can possibly carry an infectious or deadly disease. This threat has so alarmed the medical world and the public that hundreds of inventions have been devised in the last few years that address this issue, and there are now numerous patents issued that describe mechanical means and safety mechanisms to ameliorate this problem and reduce the risk of inadvertent contact with contaminated medical sharps.
Without question the risks and potential for injuries from an expended and contaminated medical sharp is both immediate in its first use, and is also long range in its final disposition as hazardous medical waste. This situation requires elaborate procedures in handling, sterilizing and final disposal such as with incineration which is in itself a problem and not a solution. Incineration can destroy the biological hazard but at high social cost. Incineration is expensive and requires large capital costs, requires a specialized facility which is expensive to build, specialized equipment which is additionally expensive, energy wasteful and increases air pollution.
Incineration operates at very high temperatures of many thousands of degrees Fahrenheit which is required for the incineration of stainless steel and which in turn often fuses materials creating new toxic compounds in the process. Other disposition practices such as microwaving, steam sterilizing, chemical and biologic treatment, or in the end, landfilling, are also complicated and expensive. Landfilling medical wastes buries the problem but is not a perfect disposal due to the destruction of real estate, abusive over use by communities, leachate flows, and the possibility of re-exposure of the hazard by gassing outflows, deluges of water, or land cover removal. Throughout the transport and the current disposal process the medical sharp remains potentially infectious and hazardous to everyone concerned. There is a high degree of risk for everyone exposed, and at a high cost for such items as medical waste for its special handling and disposal.
In the prior art we note that the emphasis is on safety caps and covers over syringe needles by mechanical means. There are many excellent examples filed in Class 604 which show mechanical covers and other means of disposing of needles after they have been used and several practical and superior methods are cited. Very few references are found wherein a solution is introduced to the needle after use.
The best example is in a two stage interacting process contained in the cap, in the U.S. Pat. No. 5,322,165 issued to Melker et al Jun. 21, 1994 wherein one stage contains a disinfectant solution. In the U.S. Pat. No.5,188,614 issued to Charles Hart Feb. 23, 1993 there is disclosed the use of a manually replaced cap containing two chambers that when pierced activate a foaming plastic.
Similar prior art is seen in U.S. Pat. No. 5,084,027 issued to Bernard Jan. 28, 1992 which has a cap containing three compartments with resins in two, and cotton wool in the third that activate and enclose the needle in a protective hardening material. There is no evidence herein of more than a disinfectant being applied.
In the prior art showing best means to cover the needle and its sharp point, we see a good example in Wesson et al, U.S. Pat. No. 4,994,046 issued Feb. 19, 1991, which discloses a slide over cover that secures in place over the needle after use. In the prior art there are also hinged caps that rotate over the needle after use which protect and shield the sharp point such as U.S. Pat. No.4,982,842 issued to Hollister, Jan. 9, 1991. Hollister references 85 patents in his patents. In U.S. Pat. No. 5,197,954 issued to Cameron, Mar. 30, 1993, a needle is sheared off and swings back alongside the syringe case after use, and optionally may be disinfected. Another invention disclosing a means to disinfect is introduced as a solution to the risk of needle contamination in U.S. Pat. No. 5,383,862 issued to Berndt et al Jan. 24, 1995. It discloses the use of a separate protecting disinfecting pouch that covers and contains the needle. Applications of disinfectant are useful but no disinfectant procedure above can satisfactorily eliminate the potential threat and problem of infectious blood material being encapsulated within the needle and held dormant in place by the capillary action of the disinfectant
Another prior art in Class 604/259 that we address is in the separate container systems located on desktops, counter tops, patient's rooms, nurse's stations, doctor's and dentist's offices, and even in homes when needles are in use, wherein the medical sharp is transported over to these containers to be disposed of. Such container systems including storage boxes to be used for a later disposal are now routine items in hospitals, clinics, and homes, and even in the emergency rooms as well as the mobile care and rescue units. The example that we cite is in U.S. Pat. No. 5,038,938 issued to Berndt Aug. 13, 1991, which discloses a disposable tray assembly housing a sealed reservoir of disinfectant that is accessed through an elastomeric plug. Any container with only a disinfectant will leave the medical sharps intact which can still stick you through the walls of a container when being handled in a normal manner for commercial or household waste.
SUMMARY OF THE INVENTION
Medical sharps such as syringe needles, lancets, suture needles, scalpels and the like are generally manufactured from stainless steel. “Stainless steel” is a term applied to a broad group of alloys of iron which contain 10 percent or more of chromium, an amount sufficient to greatly retard normal rusting and corrosion now more common from impure rain water condensation and other induced contaminants. Stainless steel is neither a specific nor an absolute term and merely indicates such a metal is less corrodable than common metals such as iron or carbon steel. Chemicals that will dissolve a solid material (usually a metal) are referred to as etchants by the metals industries. In this specification such chemicals will be referred to hereinafter as dissolvents, since their purpose here is to completely dissolve a metal sharp, as compared with the metal industry's purpose of determining grain structure.
Stainless steels are resistant to acids, salts, and alkalis and are therefore quite durable even when exposed to the dirty environment of a city dump. Thus it seemed desirable to develop a dissolvent that could eat away a medical sharp and remove the mechanical hazard of the sharp metal from our environment for all time.
Since we had to consider the types of medical stainless steels in this invention, we experimented with a variety of chemicals to see if we could find a method satisfactory and safe for corroding away the medical sharps to make them harmless. Several suitable chemical dissolvents were ultimately found that can dull a sharp immediately and dissolve a typical syringe needle in a few minutes.
This invention is thus a process for chemically disposing of a thin medical sharp with a chemical dissolvent, the dissolvent being sufficiently benign that it does not contaminate the environment. Many types of medical sharps were considered in this invention and a series of chemical solutions were developed with various effectiveness and strength. Dissolvents were formulated that can dull and remove the “sharp” surfaces in
Britton Richard B.
Woodward Malcolm P.
Srivastava V.
Weiss John G.
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