COLOR-CHANGING HEAT MATS

Abstract

Embedded thermochromic pigments address problems associated with determining whether an electrically heated mat is operating properly. At least a portion of the mat, or an attachment, includes a thermochromic pigment, such that when the mat is properly activated, the entire mat, or a region of the mat, changes color, hue or intensity, giving a visual indication as to heating status. The thermochromic pigment may change the color at a predetermined temperature associated with animal husbandry such as 80 Deg. F in conjunction with a farrowing application. One or both of the upper and lower layers of the mat may be constructed of plastic such as high-density polyethylene (HDPE), and the thermochromic pigment may be added to the plastic prior to molding the mat. Alternatively, the thermochromic pigment may be contained in a label or patch affixed to the mat material through a mold labeling process.

Claims

1. A color-changing heat mat, comprising: upper and lower layers of material defining a peripheral shape; electrical heating elements disposed between the upper and lower layers; a power cord adapted to connect the electrical heating elements to a source of electrical power; and wherein at least a portion of the upper layer of material includes a thermochromic pigment causing that portion to change color in response to heating of the elements.

2. The color-changing heat mat of claim 1, wherein the peripheral shape is rectangular, square, oval or circular.

3. The color-changing heat mat of claim 1, wherein the thermochromic pigment changes the color of the heat mat at a predetermined temperature associated with animal husbandry.

4. The color-changing heat mat of claim 1, wherein the thermochromic pigment changes the color of the heat mat at a temperature of approximately 80 Deg. F in conjunction with a farrowing application.

5. The color-changing heat mat of claim 1, wherein the thermochromic pigment changes the color of the heat mat from purple or violet to pink or magenta at a temperature of approximately 80 Deg. F in conjunction with a farrowing application.

6. The color-changing heat mat of claim 1, wherein one or both of the upper and lower layers of material are made of plastic.

7. The color-changing heat mat of claim 4, wherein the thermochromic pigment is added to the plastic prior to molding the mat.

8. The color-changing heat mat of claim 1, wherein one or both of the upper and lower layers of material are made of high-density polyethylene (HDPE).

9. The color-changing heat mat of claim 6, wherein the thermochromic pigment is added to the HDPE prior to molding the mat.

10. The color-changing heat mat of claim 1, further including an electrical controller to adjust the temperature of the mat.

11. The color-changing heat mat of claim 1, adapted for use in a farrowing environment.

12. The color-changing heat mat of claim 1, wherein the thermochromic pigment is contained in a specific localized region of the upper layer of material.

13. The color-changing heat mat of claim 1, wherein the thermochromic pigment is contained in a label or patch disposed in a specific region of the upper layer of material.

14. The color-changing heat mat of claim 13, wherein the label or patch is affixed to the upper layer of material through a mold labeling process.

15. The color-changing heat mat of claim 13, wherein the label or patch has an area in the range of 16 to 144 square inches.

16. The color-changing heat mat of claim 13, wherein the label or patch has an area in the range of 50 to 100 square inches.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1A shows an unheated mat containing a thermochromic pigment;

[0012] FIG. 1B shows the mat of FIG. 1A in a heated state;

[0013] FIG. 2A shows an unheated mat with a label or patch containing a thermochromic pigment; and

[0014] FIG. 2B shows the mat of FIG. 2A in a heated condition.

DETAILED DESCRIPTION OF THE INVENTION

[0015] This invention solves problems associated with determining heating mat ON/OFF conditions through the use of a thermo-chromic pigment added to the construction of the mat itself. In broad and general terms, this additive causes the mat to change color when heated, affording a straightforward visual confirmation.

[0016] The preferred embodiments use a thermochromic pigment in the plastic itself to make the heat mat change color depending on its temperature. This change of color provides a reliable and highly visible indication of the proper functioning of the electric heat mat.

[0017] The mats may be made of various plastic materials though high-density polyethylene (HDPE) is preferred for reasons of strength and cost. In accordance with the invention the thermochromic pigment(s) is/are added to the HDPE recipe. When the mat reaches a given trigger temperature, the color of the heat mat changes as the pigments are activated, altering visual appearance.

[0018] There are several commercial sources of thermochromic pigments. One such source of is PolyOne Corp. of Avon Lake, Ohio. Thermochromic pigments are generally colored below a set transition point and then change to a colorless state above a predetermined point. This effect can also be used to create a color shift between two colors as one of the components disappears, leaving a secondary color (for instance a green starting color transitioning to yellow once the thermochromic blue disappears). There are a wide range of primary transition colors available, as well as a variety of color shifts. Examples include orange or green to yellow (when heated); blue to green; violet to blue or magenta; brown or black to tan or red; and so forth. According to PolyOne, available transition temperatures range from 10 C. to 72 C., typically +/5 C.

[0019] In one example according to this invention, the thermochromic pigment changes the color of the heat mat from purple to pink or magenta at a temperature of approximately 80 Deg. F. While this is well-suited to the fallowing industry, the invention is not limited in this regard as different colors and transition temperatures may be used for different applications and industries, including different animals, including pets.

[0020] Other attributes of the inventive mats are as follows: [0021] In some embodiments, the mat will produce a temperature equal to 37 degrees Fahrenheit above ambient temperature. Through the use of appropriate controllers, the 37 degree differential can be reduced to meet the individual needs of the customer. [0022] The mats are available in two electrical configurations (110-120 Volts and 220-240 Volts). [0023] The mats are designed for hog farrowing crates, free stall & nursery pens. [0024] The mats create a heated surface with even heat at all points. [0025] The mats have insulated bottom to prevent downward heat loss. [0026] The mats are traction designed, non-slip surface. [0027] Double mats used in larger crates have a recess for pen dividers.

[0028] While the color-changing heat mats are ideally suited to farrowing applications, the invention is not limited in terms of the targeted animals/pets or the stages of growth. Nor is the invention limited to particular environments (i.e., farrowing crates, homes, farm, etc.); formats (i.e., rectangular, oval, square, circular, enclosures, cylinders, etc.); temperature ranges, set points, or the colors involved as the technology allows.

[0029] The mats may be produced in the following dimensions and formats (single and double widths provided by Kane Manufacturing Co., Inc. of Pleasant Hill, Iowa): [0030] PHMS 18 1818(45.7245.72 cm)mainly used for pets [0031] PHMS 28 1828 (45.7271.72 cm)mainly used for pets [0032] PHMS 36 13.536 (3091 cm) [0033] PHMS 48 13.548 (30122 cm) [0034] PHMS 60 13.560 (30152 cm) [0035] PHMS 45 18.2545(46.35114.3 cm) [0036] PHMS 57 18.2557(46.35144.78 cm) [0037] PHMD 36 2736(68.5891.44 cm) Double Mat [0038] PHMD 48 2748(68.58121 cm) Double Mat [0039] PHMD 60 2760 (68.58152.4 cm) Double Mat

[0040] The attached figures show a color-changing PHMD 36 double mat measuring 2736. This mat is constructed with upper and lower layers of HDPE housing separate heating elements in each section. In accordance with the instant invention, at least a portion of at least the upper layer of material includes a thermochromic pigment causing that portion to change color in response to heating of the elements. FIG. 1A shows a darker mat in an unheated state, whereas FIG. 1B shows a lighter mat in a heated condition.

[0041] As opposed to incorporating a thermochromic pigment into the entire article, a smaller portion, patch or label may be used. FIG. 2A shows a label 200 on a mat in an unheated state, whereas FIG. 2B shows the label in a heated condition. The label will have a specific area that will change color(s) in the same format as the entire heat changing mat. Note that the label has changed from a darker tone to a lighter one in FIGS. 2A to 2B. In this embodiment the label may be made of a polymeric composition and affixed by a process called in mold labeling. Mold labeling is the process of placing a label in the mold prior to the part being molded, such that the label is permanent. The size and/or placement of the label is variable, with the goal being that the label is visible from a reasonable distance such as 12 feet. Accordingly, for farrowing mat applications, the label will may be on the order of 11.56.5 more or less.

[0042] In alternative embodiments, the color-changing heat mats may be provided in color pairs, which correspond to different temperature trigger points. For the raising of piglets, the purple/pink color pair matches the needs of the applications; for other applications different color pairs will satisfy the customer's needs.