Syringe needle abstract
A method and apparatus are disclosed for destroying syringe needles.
The apparatus has an incinerator unit (16) into which a syringe
needle may be inserted, crimped by a crimper (30), the needle measured
between its tip and the sealing crimp, burned by passing an electric
current corresponding to its measured length between the needle
tip and the sealing crimp, and the burned needle severed by a cutting
blade (36).
Syringe needle claims
We claim:
1. A syringe needle destruction apparatus comprising a housing
having an orifice through which a syringe needle may be inserted,
a needle tip electric contact element mounted for movement along
a needle path of travel within said housing in engagement with the
needle tip between a position adjacent said orifice and a position
distal from said orifice, electric contact means mounted within
said housing adjacent said orifice for establishing an electrical
contact on the needle distally from the needle tip, measuring means
for measuring a displacement of said needle tip electric contact
element along the needle path of travel from a position adjacent
said orifice and a position distal from said orifice, means for
establishing a voltage across said needle tip electric contact element
and said electric contact means, and means for controlling and varying
the voltage established by said voltage establishing means as a
function of needle tip electric contact element displacement measured
by said measuring means.
2. The syringe needle destruction apparatus of claim 1 wherein
said needle tip electric contact element is mounted for movement
by mounting means that comprises at least one guide rod mounted
within said housing extending substantially parallel to the needle
path of travel, and a carriage movably mounted upon said rod and
spring biased towards said orifice.
3. The syringe needle destruction apparatus of claim 1 wherein
said measuring means comprises an array of juxtaposed teeth mounted
within said housing and extending substantially parallel to the
needle path of travel and means for counting the number of teeth
passed as said carriage is moved along the needle path of travel.
4. The syringe needle destruction apparatus of claim 1 further
comprising crimping means mounted within said housing adjacent said
orifice for crimping a syringe needle to substantially seal the
syringe.
5. The syringe needle destruction apparatus of claim 4 wherein
said crimping means comprises a pair of plates and motor means coupled
to at least one of said plates for imparting relative movement of
the crimping plates towards each other.
6. The syringe needle destruction apparatus of claim 1 further
comprising cutting means mounted within said housing proximal said
orifice for severing a burned portion of a needle from a substantially
unburned portion.
7. The syringe needle destruction apparatus of claim 6 further
comprising crimping means mounted within said housing adjacent said
orifice for crimping a syringe needle to substantially seal the
syringe.
8. A syringe needle destruction apparatus comprising:
means for receiving and containing a needle portion of a syringe;
means for measuring the length of the needle portion;
means for establishing a voltage across said needle portion; and
means for controlling and varying said means for establishing a
voltage as a function of needle length measured by said measuring
means.
9. The syringe needle destruction apparatus of claim 8 further
comprising severing means for severing at least a portion of a needle.
10. The syringe needle destruction apparatus of claim 8 further
comprising crimping means for forming a crimp in the needle portion
distally from a needle tip in contact with said voltage establishing
means.
11. The syringe needle destruction apparatus of claim 10 further
comprising severing means for severing the needle portion adjacent
the crimp.
12. The syringe needle destruction apparatus of claim 9 further
comprising crimping means for forming a crimp in the needle portion
distally from the needle tip in contact with said voltage establishing
means.
13. The syringe needle destruction apparatus of claim 8 wherein
said means for measuring the length of the needle portion comprises
guide means mounted within said housing extending substantially
parallel to the needle path of travel, a carriage movably mounted
upon said guide means, an array of juxtaposed teeth mounted adjacent
said carriage substantially parallel to the needle path of travel
and means for detecting and counting the number of teeth passing
past said carriage as said carriage moves along said track.
14. The syringe needle destruction apparatus of claim 13 wherein
said means for establishing a voltage comprises a needle tip contact
element mounted to said carriage for contact with a tip of the needle
and a contact element mounted to said receiving means adjacent said
carriage for contact with the needle portion distally from the needle
tip.
15. A method of destroying at least a portion of a needle that
extends outwardly from the barrel and hub of a syringe to a needle
tip, and with the method comprising the steps of:
(a) inserting a portion of the needle into an incinerator while
leaving the barrel outside of the incinerator;
(b) measuring the length of the inserted portion of the needle
within the incinerator; and
(c) burning the needle by passing an electric current through the
portion of the needle, the magnitude of the electric current being
in relation to the measured length of the needle portion.
16. The method of claim 15 further comprising the step of:
(d) forming a sealing crimp in the needle adjacent the syringe
hub.
17. The method of claim 16 further comprising the step of:
(e) severing the burned portion of the needle adjacent the crimp.
18. The method of claim 15 further comprising the step of:
(d) severing the burned portion of the needle.
19. The method of claim 15 wherein step (c) the magnitude of the
electric current is reduced as the needle is burned.
Syringe needle description
TECHNICAL FIELD
This invention relates to methods and apparatuses for destroying
syringe needles.
BACKGROUND OF THE INVENTION
Disposable hypodermic syringes are widely used in hospitals and
other medical facilities to draw body fluids from and to inject
medications into patients. These syringes are made disposable because
of the difficulties and inefficiencies involved in re-sterilizing
syringes for reuse. Because the syringes are intended to be disposed
of after use, a problem arises as to their safe post-use storage
and disposal and in preventing them from being recklessly reused
by others. Indeed, in some countries laws prohibit syringes from
being disposed of as ordinary waste since their sharp needle tips,
as well as disease causing organisms sometimes carried by them,
may injure hospital and waste disposal personnel.
To dispose of syringes safely, devices have been devised that mechanically
sever the syringe needles from their barrels. These are exemplified
by those shown in U.S. Pat. Nos. 4255996 4445644 and 4969379.
Though these devices dc prevent reuse of syringes, a sharp needle
stub remains intact and hazardous. Other types of syringe destruction
devices grind the syringes into small pieces as shown in U.S. Pat.
No. 4905916. These however do not provide for sanitary syringe
residue disposal. Furthermore, their shearing action tends to release
fluid contaminates to ambience.
Incinerators have also been used to destroy syringes is a sanitary
manner. Bulk incineration of accumulated syringes however poses
the threat of injury still occurring during accumulation and incineration
input. Thus, portable devices have been used which can incinerate
the needles by passing an electric current through them. This approach
is described in U.S. Pat. No. 4877934 and 4965426. However,
these devices leave the barrel portion of the syringe with an opening
at one end through which contaminates may emerge to ambience. Furthermore,
some pathogens contained within the needle and expelled from the
syringe during insertion are not killed by the incineration process.
Thus, another type of portable device has been devised which crimps
the needle prior to passing an electric current through it to seal
it. This type of device is shown in U.S. Pat. No. 5076178. A drawback
of this device is that an electric current large enough to burn
a long needle oftentimes causes a short needle to explode rather
than burn. This explosion of the needle can allow pathogens within
the needle to escape unharmed, often in an aerosol form. On the
other hand, a current appropriate for a short needle may take too
long a time to burn a long needle, if it does so at all.
It thus is seen that a need remains for a method and apparatus
for destroying syringe needles in a more effective and efficient
manner. It is to the provision of such that the present invention
is primarily directed.
SUMMARY OF THE INVENTION
In a preferred form of the invention, a syringe needle destruction
apparatus comprises a housing having an orifice through which a
syringe needle may be inserted, a needle tip electric contact element
mounted for movement along a needle path of travel within the housing
in engagement with the needle tip between a position adjacent the
orifice and a position distal from the orifice, and electric contact
means mounted within the housing adjacent the orifice for establishing
an electrical contact on the needle distally from the needle tip.
The apparatus also has measuring means for measuring a displacement
of the needle tip electric contact element along the needle path
of travel from a position adjacent the orifice and a position distal
from the orifice, means for establishing a voltage across the needle
tip electric contact element and the electric contact means, and
means for controlling the voltage established by the voltage establishing
means as a function of needle tip electric contact element displacement
measured by the measuring means.
In another preferred form of the invention, a method provides for
destroying at least a portion of a needle that extends outwardly
from the barrel and hub of a syringe to a needle tip. The method
comprises the steps of inserting a portion of the needle into an
incinerator while leaving the barrel outside of the incinerator,
measuring the length of the portion of the needle inserted into
the incinerator, and burning the needle by passing an electric current
through the portion of the needle, the magnitude of the electric
current being in relation to the measured length of the needle portion.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a syringe needle destruction apparatus
that embodies principles of the invention is a preferred form.
FIG. 2 is a perspective view of internal components of the apparatus
of FIG. 1 shown with the housing removed for clarity of explanation
and with its carriage in an initial position.
FIG. 3A-3F are a sequence of views, shown in cross-section, of
a portion of the apparatus of FIG. 1 showing a syringe needle being
inserted, crimped, incinerated and severed in accordance with a
method of the invention.
FIG. 4 is a flow diagram of the operation of the apparatus of FIG.
1 and method of the invention.
FIG. 5 is a perspective view of internal components of the apparatus
of FIG. 1 shown with the housing and a portion of the electric wiring
removed for clarity and with its carriage in an advanced position.
DETAILED DESCRIPTION
With reference next to the drawings, there is shown an apparatus
10 having a housing 11. The apparatus has an upper working unit
12 for syringe needle destruction operations that extends from a
lower, storage unit 13 in which residual syringe barrels may be
collected and stored. The apparatus 10 has a pivotable side door
37 with a power switch 27 mounted thereon and a viewing window 45
therethrough. The storage unit 13 has a pivotable syringe disposal
door 14 and a removable bin 29 located therein. The working unit
12 has a removable, incinerator unit 16 having a conically shaped
needle receiving orifice guide 17 mounted about a central orifice
18.
With reference next to FIG. 2 the incinerator unit 16 has guide
means in the form of a pair of guide rods 19 mounted therein above
the orifice guide 17. A spring biased carriage 20 is movably supported
for travel upon the guide rods 19. The carriage 20 bears an electrode
22 with a face that faces and is aligned with the needle orifice
18. The incinerator unit 16 has measuring means in the form of an
array of juxtaposed teeth 21 mounted therein between the guide rods
19 and a front photoelectric eye 23 and a rear photoelectric eye
24 mounted to the carriage 20. Eyes 23 and 24 are aligned so as
to sense light passing between any two adjacent teeth 21. Coil springs
25 are mounted upon the guide rods with one of their ends abutting
stop wall 42 and their opposite ends abutting the carriage so as
to bias the carriage towards the needle orifice 18. Flexible conductors
26 connect the carriage electrode 23 to a transformer 28 through
a quick disconnect coupler 35 with the carriage located in any position
along the guide rods.
A needle crimping means 30 is mounted in incinerator unit 16 closely
adjacent the needle orifice. The crimping means comprises an upper
crimping plate 31 pivotably mounted on a pivot pin 34 above the
orifice 18 and a stationary lower crimping plate 32 rigidly mounted
below the needle orifice 18. The lower plate 32 also functions as
an electrode and a conductor 33 electrically couples it with the
transformer 28 through a quick disconnect coupler 47.
The apparatus also has means for severing needles that includes
a pivotable cutting blade or shearing plate 36 pivotable mounted
on a pivot pin 34 in sliding contact with the rear side of the upper
crimping plate 31. Both the upper crimping plate 31 and the blade
36 extend through aligned openings in the wall of the incinerator
unit 16 so that one of their end portions extends from the incinerator
unit. An electric motor 40 mounted in the working unit 12 has
its power output drive shaft coupled with both a crimping cam 38
and a cutting cam 39. The motor is electrically coupled to a controller
41 which is of conventional construction that preferably employs
a microprocessor such as a 20 pin Motorola HC 6805 made by Motorola
Inc. of Austin, Texas. An ultraviolet light 43 mounted in the incinerator
unit 16 is also coupled with the controller 41 by a pair of conductors
44. A system ready LED type indicator lamp 48 a trouble/burn process
LED type indicator lamp 49 and a full status LED type indicator
lamp 50 are all mounted to the front of the working unit 12. Additionally,
an unshown error code lamp is mounted within the lower unit 13 that
is viewable through viewing window 45. Each of these lamps is electrically
connected to the controller 41 while photoelectric eyes 23 and
24 are connected to the controller by conductors 52. The transformer
28 itself is coupled to the controller 41. An unshown high temperature
sensor is mounted on the transformer 28 which is coupled with the
controller.
An electromagnetic burn done switch 55 is mounted within the incinerator
unit 16 so that the carriage 20 closes an electric circuit when
it is positioned closely adjacent the orifice 18. An unshown motor
home or cycle complete sensor is mounted adjacent the motor 40 to
indicate that the cams have completed a full cycle and have returned
to their initial, apparatus-ready positions prior to apparatus activation.
OPERATION
Operation of the apparatus may best by understood by reference
to FIGS. 3A-3F and FIG. 4. With the power switch 27 positioned on,
a conventional syringe S having a barrel B, a plastic needle hub
H, and a metallic needle N is guided by an operator, such as a nurse,
nurse's aid, or hospital attendant, into the needle receiving orifice
18 as shown in FIG. 3A. The conical shape of the orifice guide
17 serves to guide the needle tip into and through the orifice 18.
As the needle N is pushed into the incinerator unit 16 it passes
between the crimping plates 31 and 32 bringing its tip into contact
with the carriage electrode 22. As the needle is pushed further
into the unit it drives the carriage 20 away from the orifice 18
along guide rods 19 against the bias provided by spring 25 as
shown in FIG. 3B. The carriage is moved in this manner until either
the syringe hub H abuts the conical orifice guide 17 as shown in
FIG. 3C, or until the carriage has traveled the maximum distance
allowed by the guide rods 19 by engaging carriage stop wall 42.
Carriage movement is limited to insure that an operator does not
attempt to incinerate the entire length of an extraordinarily long
needle in a single operations and thereby exceed power capacity
limits. Such long needles are instead incinerated in a succession
of operations as such operations are herein described.
As the carriage is driven away from the orifice 18 the front photoelectric
eye 23 senses the light passing between the first and second tooth
21 the rear photoelectric eye 24 quickly thereafter also senses
this light. This sensing sequencing of the sensors indicates to
the controller that the carriage is moving forward, meaning away
from orifice 18 and a reversing of this sensing sequence indicates
a backwards movement of the carriage. The controller determines
the length of the needle from the distance the carriage has moved
from the orifice. This is done by calculating the number of teeth
the eyes have traveled past in the forward direction. An increase
in the determined length of the needle results in the controller
increasing the power setting of the transformer, i.e. the magnitude
of the electric current, to insure that needles of all lengths are
provided with a current which properly burns them. For example,
as a needle moves the carriage between its initial position adjacent
orifice 18 and a distance 1/4 inch therefrom, the controller sets
the current at 25% of the maximum current of the transformer. As
the carriage is driven further along the guide rails to a distance
of between 1/2 to 1 inch from its initial position the power level
is set at 50%. From 1 to 11/2 inches from its initial position the
power level is set to 75%, and from 11/2 inch to a maximum carriage
distance of approximately 3 inches from its initial position the
power level is set at 100%. The preferred transformer here is rated
for 7 volts A.C. and for a maximum current of 40 amps as high current
could cause sparking and welding of the needle to the electrodes.
Once the syringe needle N is fully inserted into the incinerator
unit 16 as shown in FIG. 3C, a sensed momentary pause in carriage
motion for a preselected time period is detected by the photoelectric
eyes 23 and 24 which causes the controller to energize the motor
40 and the trouble/burn process lamp 49 and de-energize the system
ready lamp 48. The motor then commences to rotate the crimping cam
38 and the cutting cam 39. The crimping cam 38 engages and pivots
the upper crimping plate 31 about pivot pin 34 thereby crimping
needle N between the upper crimping plate 31 and the lower crimping
plate 32 as shown in FIG. 3C. The crimping of the needle serves
the dual function of sealing the syringe needle residual stub and
providing an electric contact with the needle at the crimp site
since the lower plate 32 also functions as an electrode. With the
needle crimp still held firmly by the plates 31 and 32 the controller
next energizes the electrodes 23 and 32 by coupling them with the
transformer 28 causing the selected current based on the length
of the needle to flow through it causing the needle portion to burn
and char.
During the brief period of incineration, the spring 25 continuously
urges electrode 22 towards electrode 32. This serves to maintain
them in good contact with the needle and also to create a compaction
force on the needle char to lengthen the time that the charring
needle provides a conductive path between the electrodes. As incineration
progresses and the needle weakens it becomes unable to hold the
electrodes apart. As a result, the carriage and electrode 23 then
advance towards the crimping means, as shown in FIG. 3D. This causes
the needle to fold and twist which usually forms it into a compact,
single extension needle residue char of a coil-like shape that usually
remains attached to the unburned portion of the needle at its crimp.
As the needle weakens and the carriage is advanced toward the crimping
means the controller reduces the current passing through the needle
in similar fashion to that previously described with reference to
the position of the carriage with respect to the selected current
level. The reduction of the current extends the useful life of the
electrode, decreases power consumption, decreases the chances of
sparking and welding of the needle to the electrodes, and decreases
the chances of exploding the needle due to passing too large a current
through the needle.
As the returning carriage nears its initial position adjacent the
crimping means 30 the carriage closes the electromagnetic burn
done switch thus indicating to the controller that the burn process
is complete. The controller then de-energizes the electrodes just
prior to the carriage returning to its initial position. This prevents
an arcing between the electrodes and a welding of the needle to
the electrodes. If the burn done switch has not been interrupted
after expiration of a preselected time period, such as two seconds
from the time of burn initiation, the controller de-energizing the
motor 40 to allow the needle to burn for an additional 2 second
time period and then re-energizes the motor and de-energizes the
electrodes. The cutting cam 39 is now rotated to a position forcing
the cutting blade 36 downward through the needle char closely adjacent
the crimp. The cutting blade severs the residue char N' whereupon
it free falls, as shown in FIG. 3E, to the bottom of the incinerator.
Finally, as shown in FIG. 3F, with the crimping plates once again
separated the needle crimp is released enabling the operator to
remove the syringe and its short, sealed, needle stub from the incinerator
unit 16 and place it in the lower storage unit 13.
Should the electromagnetic switch 55 indicate that the carriage
has not returned to its initial position after a burn cycle, the
controller will attempt to clear the fault by energizing motor 40
to initiate 3 cycles of the crimping plate and cutting blade 36.
If the carriage has still not returned the controller causes the
display of an error code on the error code lamp and prevents the
initiating of another burn cycle.
Once the cams have fully returned to their initial positions the
motor home sensor inputs a signal to the controller 41 which de-energizes
the motor 40 re-energizes the system ready lamp 48 and de-energizes
the trouble/burn process 49 to indicate that the apparatus is reset
and ready to incinerate another needle.
Though most pathogens within the needle are killed by their incineration,
some heat resistant ones may not be. Also, some pathogens may be
expelled during insertion and operation of the needle into the apparatus.
For these reasons the incinerator is also provided with a germicidal
ultraviolet light 43 which is energized by the controller for a
short time following needle severance to kill such remaining pathogens.
Finally, the controller also counts the number of burn cycles completed
so that after a preselected number of cycles the controller will
flash the full status lamp 50 for a 72 hour grace period. If the
incinerator unit 16 is not replaced within this grace period the
full status lamp is continuously illuminated and the controller
will not initiate another burn cycle.
From the foregoing, it is seen that a method and apparatus for
destroying syringe needles is now provided which overcomes problems
associated with those of the prior art. It should however be understood
that the just described embodiment merely illustrates principles
of the invention in a preferred form. Many modifications, additions
and deletions may, of course, be made thereto without departure
from the spirit and scope of the invention as set forth in the following
claims.
|