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1. WO1992017040 - COFFRET CHAUFFANT POUR LIQUIDES PARENTERAUX, SYSTEME ET METHODES

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]
other low thermal mass heater is not further described.
Low thermal mass heater 14 » comprises a stand 740, a captured layer of thermal insulation 710, a flexible film heater layer 730 and a heat distribution layer 720.
Stand 740 comprises an outer leg 704 on each lateral side of heater 14* and a plurality of inner supports 702.
Stand 740 is made from rigid synthetic resinous material. The film heater layer 730 is disposed above thermal insulation layer 710 which is captured in a recess 712 in the top of stand 740. Thermal insulation layer 710 comprises a relatively thick layer when compared to the thickness of film heater layer 730 and is made from highly thermally insulating material. The insulating material may be paper.
Film heater layer 730, best seen in Figure 19, comprises a plurality of thin conductors 732 and 734 prepared in a manner similar to that of printed wiring. So made, the resistance of end conductor 732 and 734 is varied end to end to provide an area of greatest heat output where heat absorption by the parenteral fluid flowing through cassette 20 or 20' is the greatest. Film heater layer 730 may be a Flexible Thermofoil Heating Element or a Glass Reinforced Silicon Rubber Heater manufactured and distributed by Minco Products, Inc. , 7300 Commerce Lane, Minneapolis, Minnesota 55432.
Heat distribution layer 720 is disposed at the interface between cassette 20 or 20' and film heater layer 730 and is bonded or otherwise adhesively attached to film heater layer 730. Heat distribution layer 720 comprises sufficient heat capacity to provide a
homogenous temperature at the interface, yet is
sufficiently thin the provide a rapid thermal response, to lower foil 200 which comprises a similar pressured surface 206 to surface 722 contact with heat distribution layer 720 as earlier described above for the contact between cassette 20 and heating plate 14. Heat
distribution layer 720 comprises a planar pattern similar to the pattern of top surface 82 of heating plate 14 such that the top surface 722 of thermal distribution layer 720 fits within the perimeter of medial access 108 or 108' of cassette 20 or 20', respectively.
Provided as a part of film heater layer 730 is at * least one thermal sensor 786 which measures the
temperature of the heat distribution layer 720. In the currently preferred embodiment, at least two thermal sensors are used to provide redundancy of measurement whereby a poorly performing sensor 786 is detected and an alert is thereby provided, as earlier described.
Low thermal mass heater 14 ' comprises a pair of grooves 706, on each side, one of which is seen in Figure 18. The grooves provide for facile, tongue-in-groove insertion into an instrument in the same manner as guide rails 64 provide insertion for heating plate 14.
Electrical connection of low thermal mass heater 14 * is made in the same way as heating plate 14 is connected.
The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as
illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
What is claimed and desired to be secured by Letters Patent is:

The Claims
1. Apparatus (20,20' , 12, 14,540) for safely and efficiently heating parenteral fluids characterized by a disposable, heat energy transfer cassette (20,20') comprising:
means (100) for stiffening and supporting the cassette (20,20') comprising inlet and outlet pathways (116,126) and fluid flow accessing means
(112,114,122,124) therefor;
means for constraining flow between the inlet and outlet pathways (200,300,400), wherebetween said
parenteral fluid heating occurs, the flow constraining means (200,300,400) further characterized by:
a first heat transmitting flexible foil layer
(200) which comprises at least one physiologically inert parenteral fluid contacting side (204) ;
a second heat transmitting flexible foil layer (400) which also comprises at least one
physiologically inert parenteral fluid contacting side (406) ;
a spacer layer (300) interposed between and
bonded to the two heat transmitting layers
(200,400), said spacer layer (300) defining a
serpentine path (300,314,320,324) for fluid flow
between the inlet and outlet pathways (116,126);
at least two inlet and outlet pathway
communicating ports (212,224) in the first heater contacting layer (200) providing access between the inlet pathway (116) and serpentine path
(300,314,320,324) at one upstream site (114) and
access between the serpentine path (300,314,320,324) and outlet pathway (126) at a downstream site (124) ; means (180) for restricting flow at the downstream site (124) such that pressurized influent parenteral fluid flow is restricted and therefore exerts pressure outwardly against the first and second layers (200,400) thereby causing at least a portion of each first and second layer (200,400) to balloon slightly to thereby make positive contact with at least one heater plate (12,14) externally juxtaposed at least one of the first and second layers (200,400).

2. Apparatus (20,20' ,12,14,540) according to claim 1 wherein the stiffening and supporting means (100) comprise a temperature connecting site (132,132')
disposed along the outlet pathway whereby the temperature of effluent fluid is sensed.

3. Apparatus (20,20' ,12,14,540) according to claim 1 wherein the stiffening and supporting means (100) comprise parts (160, 160* ,170, 170') which protrude outwardly and downwardly from the plane of the spacer layer (300) to provide thickness for connection of input and output tubes (110,120).

4. Apparatus (20,20' ,12,14,540) according to claim 3 further characterized by heating means (12,14) which comprise outward projections ((26,28,32,34) which
juxtapose the protruding parts (160,160* ,170,170') of the stiffening and support means (100) thereby providing support and protection for the protruding parts
(160,160',170,170') .

5. Apparatus (20,20' ,12, 14,540) according to Claim 1 further comprising juxtaposed heating plates (12,14) of a predetermined shape wherebetween the cassette (20,20') is disposed.

6. Apparatus (20,20* ,12,14,540) according to Claim 5 wherein the heat energy transfer cassette (20,20') comprises accessible planar heat conducting surfaces of the heat transmitting layers (200,400) for efficient contact with the heating plates (12,14).

7. Apparatus (20,20' , 12,14,540) according to Claim 6 wherein the heat energy transfer cassette (20,20') comprises exposed upper and lower surfaces (204,406) of the heat transmitting flexible foil layers (200,400) which conform to the shape of and therefore nest with juxtaposed surfaces (82,46,48) of each associated heating plate (12,14), thereby providing facile, accurate
placement of the cassette (20,20') means between the heating plates (12,14).

8. Apparatus (20, 20 ' , 12 , 14 , 540) according to Claims 1 wherein the heat transmitting foil layers (200,400) comprise aluminum foil.

9. Apparatus (20,20' , 12, 14,540) according to Claim 8 wherein the heat transmitting foil layers (200,400) comprise silver plated copper foil.

10. Apparatus (20,20' , 12, 14,540) according to Claim 8 wherein the heat transmitting foil layers (200,400) comprise silver foil.

11. Apparatus (20,20* , 12,14,540) according to Claim 8 wherein the heat transmitting foil layers (200,400) comprise thermally conductive plastic foil.

12. Apparatus (20,20' , 12,14,540) according to Claim 1 further characterized by attached influent and effluent tubes (110,120) for facile connection to fluid sources and patient infusion connections.

13. Apparatus (20,20* ,12,14,540) according to Claim 1 wherein the cassette (20,20*) is further characterized by means (130) for sensing the temperature disposed at least at the outlet (124) of the serpentine pathway
(300,314,320,324).

14. Apparatus (20,20* ,12,14,540) according to Claim 1 further comprising:
means (540) for receiving and supporting the fluid cassette (20,20*) for heating and automatic controlling of temperature therein, said heating and supporting means. (540) characterized by:
a first heating plate (12) releasibly installable in the receiving and supporting means (540) ;
a second heating plate (14) releasibly installable in the receiving and supporting means (540) ;
said receiving and supporting means (540) further comprising:
means (564,566) for supporting the second
heating plate (14) , said second plate (14)
supporting means (564,566) comprising a static
support;
means (588,592,594,590,542,544) for supporting the first heating plate (12) , the first heating
plate supporting means (588,592,594,590,542,544)
comprising rail guide means (542,544) and means
(588,592,594) for reciprocally moving said rail
guide means (542,544) toward the second heating
plate (14) for purposes of applying restraining
pressure against cassette (20,20') interposed
therebetween and away from the second heating plate for purposes of releasing and removing the cassette
(20,20') for facile removal therefrom.

15. Apparatus (20,20* , 12, 14,540) according to Claim 1 further characterized by:
means (550) for housing parts of the apparatus
(540);
a first heating plate (12) comprising at least one • heating element (492,494,496,498) and releasibly disposed in said housing means (550) ;
a second heating plate comprising at least one heating element (492,494,496,498), the second heating plate (14) releasibly disposed in the housing means (550) and juxtaposed and in contact with the heat transmitting foil layers (200,400) of the cassette (20,20*) when in use;
means (554,556* ,558,572,582, 680) for controllably adjusting heat transmitted to the warming fluid whereby the heating elements (492,494,496,498) are controlled to heat the parenteral fluids to a predetermined
temperature;
means (86,670) for determining proper operation of the heating elements (492,494,496,498) by monitoring current flow through each of the at least one heating elements (492,494,496,498) when each of the at least one heating element (492,494,496,498) is on.

16. Apparatus (20,20* , 12, 14,540) according to claim 15 wherein the first heating plate (12) comprises a heating block partially divided into at least two
sections (46,48) thereby providing substantial thermal separation and at least one pair of temperature sensors (86) in each of the at least two sections (46,48) whereby the comparative temperature measurements of each sensor

(86) of each pair of temperature sensors provides a first operational safety test.

17. Apparatus (20,20' ,12,14,540) according to claim

16 wherein the second heating plate (14) comprises a heating block (36,38) similarly thermally divided to produce like thermal separation whereby the comparative temperature measurements provide a second safety test.

18. Apparatus (20,20* ,12,14,540) according to claim

17 further characterized. by means for comparing
temperatures of the first heating plate (12) and of the second heating plate (14) to provide a third safety test.

19. Apparatus (20,20' , 12, 14,540) according to Claim 1 further characterized by:
variable means (130,610,680,554,556' ,558) for setting and regulating variable and regulatable
temperature set points, said setting and regulating means comprising:
means (680,554,556' ,558) for setting a
temperature which provides a set point to which the fluids are heated;
means (130) for sensing temperature of effluent warmed fluids.
means (670,610) for responsibly controlling
heating of fluids passing through the apparatus
(540) such that the effluent fluid temperature is substantially the same as the set point temperature.

20. A process for making a cassette (20,20') wherein parenteral fluids are efficiently heated,
comprising the steps of:
pretreating a supporting frame (100) of the cassette (20,20*) with adhesive which is physiologically inert at predetermined sites;
disposing the supporting frame (100) upon an
accessible surface to provide access to a depression (144,144') in the top of the frame;
placing a first flexible foil (200) which is also physiologically inert onto the frame (100) such that it nests in the depression (144,144');
compressively bonding the first foil (200) to the frame (100) and allowing the bonded pair (100,200) to cool;
placing a spacer (300) comprising adhesive on both sides and a hollow serpentine path (300,314,320,324) such that it nests in said depression (144,144') on top of the first flexible foil (200) ;
disposing a second foil (400) on top of the spacer (300) such that the serpentine path (300,314,320,324) is covered;
applying pressure to the top of the second foil (400) to compressively bond the first and second foils (200,400) to opposite sides of the spacer (300) to form a completed cassette (20,20') and permitting the cassette (20,20') to cool.

21. A method for efficiently heating parenteral fluids in a cassette (20,20* ), characterized by the steps of:
disposing a cassette (20,20') comprising flexible, physiologically inert foils (200,400) and a therewith covered spacer (300) which defines a serpentine path (300,314,320,324) through which the parenteral fluid flows between two heating plates (12,14) disposed on opposite sides of the cassette (20,20*) and thereat in contact with at least a portion of the cassette (20,20'); introducing pressurized parenteral fluid flow into the cassette (20,20*);
as a result of an orifice (180) which is resistant to parenteral fluid flow disposed at an effluent port (122) of the cassette (20,20*), ballooning the flexible, physiologically inert foils (200,400) outwardly to thereby make heat efficient contact which said heating plates (12,14) over substantially the common surface area between the heating plates (12,14) and cassette (20,20').