1. A catalyst for the production of polyester, comprising:
(a) a titanium component comprising at least one titanium compound; (b) a sulphur-containing silicate; and (c) at least one substrate material with a specific surface area of 400 m2g or more, wherein the at least one substrate material comprises a mixture of clay and activated charcoal, wherein the catalyst contains the titanium component in a quantity that results in 10 to 15 ppm of titanium in the polyester produced, wherein the sulphur-containing silicate and the titanium in the titanium component are present in a weight ratio of 0.5:1 to 5:1, and wherein activated charcoal and clay are present in a weight ratio of 0.5:5 to 0.5:20.
2. The catalyst according to claim 1, wherein the titanium component comprises at least two titanium compounds.
3. The catalyst according to claim 1, wherein the sulphur-containing silicate is an alumosilicate.
4. The catalyst according to claim 1, further comprising ethylene glycol.
5. The catalyst according to claim 1, wherein the titanium compound is selected from the group consisting of tetra-n-butyl orthotitanate, tetra isopropyl titanate and mixtures thereof.
6. The catalyst according to claim 1, wherein the sulphur-containing silicate and the titanium in the titanium component are present in a weight ratio of 1:1 to 2:1.
7. The catalyst according to claim 1, wherein the activated charcoal to clay in a weight ratio of 1:5 to 1:20.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An air probe de-icing system comprising:
a first solid-state heating element with a selected wattage rating, having a first integrated heating control;
a second solid-state heating element with a selected wattage rating, having a second integrated heating control, and said second solid-state heating element is electrically connected in parallel with said first solid-state heating element; and
wherein the selected wattage rating for each of said first solid-state heating element and said second solid-state heating element are selected to be at least as large as a total system heating load such that if one of said first or said second solid-state heating elements fails, the remaining solid-state heating element can handle the total system heating load so as to provide system redundancy.
2. The air probe de-icing system of claim 1 wherein the selected wattage rating of said first solid-state heating element is equal to the selected wattage rating of said second solid-state heating element.
3. The air probe de-icing system of claim 1 wherein the selected wattage rating of said first solid-state heating element is different from the selected wattage rating of said second solid-state heating element.
4. The air probe de-icing system of claim 1 wherein the first and the second integrated heating controls each control the respective solid-state heating elements they are associated with by changing the resistance of said solid-state heating elements respectively.
5. The air probe de-icing system of claim 4 wherein the first and the second integrated heating controls are self-regulating.
6. The air probe de-icing system of claim 5 wherein the first and the second integrated heating controls are self-synchronizing.
7. The air probe de-icing system of claim 1 wherein said first and said second solid-state heating elements are electrically connected to source of electrical power.
8. An air probe de-icing system comprising:
a solid-state heating unit having:
a first solid-state heating element, for generating heat to de-ice the air probe, having a power rating and integral self-regulating heating control;
a second solid-state heating element, for generating heat to de-ice the air probe, having a power rating and integral self-regulating heating control,
a third solid-state heating element, for generating heat to de-ice the air probe, having a power rating and integral self-regulating heating control, and said third solid-state heating element is electrically connected in parallel with said first and said second solid-state heating elements;
an electrical power source, for generating electrical power, electrically connected to said first, second and third solid-state heating elements,
wherein the various power ratings are selected such that in the event any one solid-state heating element fails, the remaining solid-state heating elements can handle the total system heating load so as to provide system redundancy.
9. The air probe de-icing system of claim 8 wherein the various power ratings of the solid-state heating elements are equal to each other.
10. The air probe de-icing system of claim 8 wherein the various power ratings of the solid-state heating elements are different from each other.
11. The air probe de-icing system of claim 8 wherein the integral self-regulating heating controls of said first, second and third solid-state heating elements each control the respective solid-state heating elements they are associated with by changing a resistance of the respective solid-state heating element.
12. The air probe de-icing system of claim 8 wherein the integral self-regulating heating controls of said first, second and third solid-state heating elements are self-synchronizing.
13. A method for de-icing an air probe comprising the steps of:
determining a total system heating load;
selecting a first solid-state heating element having a specific wattage rating that is at least equal to the total system heating load;
providing a first integrated heating control, for controlling the first solid-state heating element;
selecting a second solid-state heating element having a specific wattage rating that is at least equal to the total system heating load;
providing a second integrated heating control, for controlling the second solid-state heating element;
electrically connecting the first solid-state heating element in parallel with the second solid-state heating element; and
controlling the first and the second solid-state heating elements with the first and the second integrated heating controls respectively such that the power emitted by the first solid-state heating element is less than the specific wattage rating for the first solid-state heating element, and the power emitted by the second solid-state heating element is less than the specific wattage rating for the second solid-state heating element.
14. The method for de-icing an air probe according to claim 13 wherein the specific wattage rating of the first solid-state heating element is equal to the specific wattage rating of the second solid-state heating element.
15. The method for de-icing an air probe according to claim 13 wherein the specific wattage rating of the first solid-state heating element is different from the specific wattage rating of the second solid-state heating element.
16. The method for de-icing an air probe according to claim 13 wherein the step of controlling the first and the second solid-state heating elements with the first and the second integrated heating controls respectively further comprising the step of utilizing the first and the second solid-state heating elements to measure the air temperature and then changing a resistance of the first and the second solid-state heating elements respectively based upon the measured air temperature.
17. The method for de-icing an air probe according to claim 13 wherein the first and the second integrated heating controls are self-regulating.
18. The method for de-icing an air probe according to claim 17 wherein the first and the second integrated heating controls are self-synchronizing.
19. The method for de-icing an air probe according to claim 13 further comprising the steps of:
providing an electrical power source; and
electrically connecting the electrical power source to the first and the second solid-state heating elements.