Elapsed time indicator

• US 4,229,813 A
• Filed: 06/26/1978
• Issued: 10/21/1980
• Est. Priority Date: 06/26/1978
• Status: Expired due to Term

• Current Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Original Assignee: Akzona Incorporated (Nouryon BV)
• Inventors: Lilly, Robert L., Tummers, Gerardus L. J., Johnson, Claude D., Davis, Roger D.
• Primary Examiner(s): Yasich, Daniel M.
• Application Number:
  US05/919,005
• Time in Patent Office: 848 Days
• Field of Search: 116/206, 116/207, 116/219, 116/200, 73/356, 58/1 R, 368/89
• US Class Current: 368/89
• CPC Class Codes: G04F 13/06 using fluidic means

Abstract

A time indicator which is substantially unaffected by variations in temperature. The indicator utilizes a silicone oil which is slowly absorbed onto and moves up a porous strip at a rate which is a function of time. One side of the strip is printed with an oil soluble ink, while the other side is unprinted. The printed side of the strip is laminated with polyethylene film to an unprinted strip. As the silicone oil moves up the strip, the oil contacts the ink causing a dye in the ink to migrate from the printed side to the unprinted side, thus providing a measurable color front moving up the strip. The oil is contained in a frangible ampul and a sponge with a small hole at the bottom is situated between the ampul and the strip. The indicator is substantially unaffected by normal variations in temperature and humidity.

Claims

1. A time indicator device comprising:

a reservoir, said reservoir containing dimethylpolysiloxane;

a porous indicator member, one side of said porous member being impregnated with a dye, said dye being at least slightly dispersible in said dimethylpolysiloxane;

said reservoir and said porous member being in a close relationship with one another;

said dimethylpolysiloxane adapted to escape from said reservoir upon activation of said reservoir wherein said dimethylpolysiloxane will spread onto said porous member, said dimethylpolysiloxane wetting said porous member thus permitting said dye to flow from said one side of said porous member to the other whereby the movement of said dimethylpolysiloxane on said porous member provides an indication of the passage of time, said dimethypolysiloxane being substantially independent of temperature and relative humidity.

2. A device as set forth in claim 1 wherein said dimethylpolysiloxane has a viscosity between 7-100,000 centistokes.

3. A device as set forth in claim 2 wherein said dimethylpolysiloxane has a viscosity of approximately 500 centistokes.

4. A device as set forth in claim 1 further including an absorbent barrier means situated between said reservoir and said porous indicator member for preventing said dimethylpolysiloxane from prematurely moving onto remote portions of said indicator member upon activation.

5. A device as set forth in claim 4 further including a hole in said absorbent barrier, said hole providing a flow path for said dimethylpolysiloxane onto a predetermined portion of said porous indicator means.

6. A device as set forth in claim 4 further including means to attach said device to intravenous tubing.

7. A device as set forth in claim 1 further including a housing covering said reservoir and said porous indicator member.

8. A device as set forth in claim 7 wherein said housing includes a first optically clear portion contiguous with said porous material providing a visual indication of the elapse of time.

9. A device as set forth in claim 8 further including time indicia associated with said optically clear portion.

10. A device as set forth in claim 9 further including a second optically clear portion adjacent to said reservoir, said hole in said porous barrier being situated near said second optically clear portion, whereby upon the breaking of said reservoir, an immediate indication of activation is indicated.

11. A device as set forth in claim 1 wherein said porous indicator member is a composite piece having a first and second strip of porous material being adhered to each other, the side of one of said strips adjacent the other of said strip having said oil soluble dye printed thereon.

12. A device as set forth in claim 1 wherein said dye is taken from the group consisting of Sudan Red O, Sudan Orange, Sudan Blue, a mixture of Sudan Red O and Sudan Orange, Sudan IV and Sudan I.

13. A device as set forth in claim 12 where said dye is Sudan Red O.

14. A device as set forth in claim 1 further including an amount of ethyl acetate mixed with said dye.

15. A device as set forth in claim 1 further including an amount of polyisobutylene mixed with said dye for preventing said dye from prematurely penetrating to the other side of said porous indicator member.

16. A time indicator comprising:

a frangible ampul;

a liquid contained in said ampul;

an indicator strip located in a close proximity to said ampul;

a sponge forming a reservoir of said liquid after said ampul is broken, said sponge substantially separating said ampul from said strip, whereby the deposition of said liquid onto said strip is controlled by said sponge, said sponge further preventing said liquid from splattering onto said strip upon the breaking of said ampul, said sponge including means to control flow of the liquid.

17. An indicator as set forth in claim 16 wherein said flow controlling means said sponge further includes a hole therethrough whereby said liquid is initially deposited on a predetermined place on said strip.