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To provide chilled water, a variable-primary-flow system includes two variable speed pumps that pump water through a first chiller and a second chiller. A control energizes the second chiller in response to a cooling demand exceeding that what can be met by the first chiller operating alone, and de-

To provide chilled water, a variable-primary-flow system includes two variable speed pumps that pump water through a first chiller and a second chiller. A control energizes the second chiller in response to a cooling demand exceeding that what can be met by the first chiller operating alone, and de-energizes the second chiller upon the cooling demand decreasing to a level below the first chiller's maximum capacity. When both chillers are operating, the capacities of the chillers are modulated in unison to meet the cooling demand. Likewise, when both pumps are running, their speed is modulated in unison to provide a desired pressure.

대표청구항 ▼

To provide chilled water, a variable-primary-flow system includes two variable speed pumps that pump water through a first chiller and a second chiller. A control energizes the second chiller in response to a cooling demand exceeding that what can be met by the first chiller operating alone, and de-

To provide chilled water, a variable-primary-flow system includes two variable speed pumps that pump water through a first chiller and a second chiller. A control energizes the second chiller in response to a cooling demand exceeding that what can be met by the first chiller operating alone, and de-energizes the second chiller upon the cooling demand decreasing to a level below the first chiller's maximum capacity. When both chillers are operating, the capacities of the chillers are modulated in unison to meet the cooling demand. Likewise, when both pumps are running, their speed is modulated in unison to provide a desired pressure. nd c. means for heating the heating die an amount sufficient to seal the top and bottom webs to each other at areas thereof that contact the heat sealing grid. 4. The apparatus of claim 3 wherein the anvil is a cylinder of uniform diameter between the heating die rails. 5. The apparatus of claim 2 wherein the top and bottom webs each have a predetermined thickness, and wherein the anvil and the heat sealing grid of the heating die cooperate to form a nip with a clearance that is approximately equal to the thicknesses of the top and bottom webs. 6. The apparatus of claim 2 further comprising means for applying a force that keeps the heating die rails in contact with the anvil. 7. Apparatus for processing a continuously moving flexible top web, a continuously moving flexible bottom web, and discrete flexible articles held at predetermined alignments and spacings between the webs into individual products comprising: a. means for producing a tension in the top and bottom webs and in the articles that maintains the predetermined alignment and spacings of the articles between the webs; b. means for heat sealing the top and bottom webs to each other around the articles, wherein the means for sealing the top and bottom webs comprises: i. a rotatable heating die having spaced apart circumferential rails of a first diameter, and a heat sealing grid of a second diameter less than the first diameter between the rails, the heat sealing grid defining at least one pocket; ii. a rotatable anvil in contact with the heating die rails, the anvil cooperating with the heating die heat sealing grid to form a nip through which the top and bottom webs pass such that the articles enter said at least one pocket, wherein: the nip between the heating die heat sealing grid and the anvil defines a nip plane; the means for producing a tension comprises a guide rod having a first axially extending line at a first distance from the nip plane and a second axially extending line opposite the first axial line, and a wrap roller having a first axially extending line at a second distance less than the first distance from the nip plane, the guide rod first axial line being spaced farther from the nip plane than the wrap roller first axially extending line; and the top and bottom webs and the articles are in contact with the guide rod first axial line and with the wrap roller first axial line; and iii. means for heating the heating die an amount sufficient to seal the top and bottom webs to each other at areas thereof that contact the heat sealing grid; and c. means for cutting the sealed top and bottom webs around each article to thereby produce individual products each consisting of a selected one of the discrete articles and selected portions of the top and bottom webs, so that the guide rod and the wrap roller cooperate to wrap the top and bottom webs and the articles in a reverse bend that produces a tension in the webs and articles that maintains the predetermined alignments and spacings of the articles between the webs. 8. The apparatus of claim 7 wherein the first axial line of the wrap roller lies in the nip plane. 9. The apparatus of claim 8 wherein the second axial line of the guide rod and the first axial line of the wrap roller lie in the nip plane. 10. The apparatus of claim 9 wherein the wrap roller has a first diameter, and the guide rod has a second diameter less than the first diameter. 11. The apparatus of claim 7 wherein the guide rod is adjustable in directions parallel to and perpendicular to the nip plane. 12. A multi-web processing machine that continuously manufactures products comprising: a. means for continuously drawing in a downstream direction a composite web consisting of first and second webs and multiple discrete flexible articles held by friction between the first and second webs in a predetermined alignment and with predetermined spacings therebetween along the downstream direction; b. a rotary heat sealing system comprising: i. means for producing a tension in the composite web that maintains the predetermined alignment and spacing of the articles between the first and second webs; and ii. means for sealing the first and second webs to each other around each of the articles; and c. means for cutting the first and second webs in directions parallel to and transverse to the downstream direction into individual products each consisting of a single selected article and of selected portions of the first and second webs. 13. The multi-web processing machine of claim 12 wherein the means for sealing the first and second webs comprises: a. a pair of transversely spaced side plates; b. an anvil rotatably mounted in the side plates; c. a heating die having spaced apart rails of a first diameter and in contact with the anvil at selected locations thereon, and a heat sealing grid between the rails and having a second diameter less than the first diameter and cooperating with the anvil to form a nip through which the composite web is drawn in the downstream direction, the heat sealing grid defining at least one pocket that receives the articles as the composite web is drawn in the downstream direction; and d. means for heating the heating die heat sealing grid an amount sufficient to seal the first and second webs to each other at areas that correspond to the heating die heat sealing grid. 14. The multi-web processing machine of claim 13 wherein the anvil is a cylinder having a uniform diameter between the selected locations thereof in contact with the heating die rails. 15. A multi-web processing machine that continuously manufactures products comprising: a. means for continuously drawing in a downstream direction a composite web consisting of first and second webs and multiple discrete flexible articles held by friction between the first and second webs in a predetermined alignment and with predetermined spacings therebetween along the downstream direction; b. a rotary heat sealing system comprising: i. means for producing a tension in the composite web that maintains the predetermined alignment and spacing of the articles between the first and second webs; and ii. means for sealing the first and second webs to each other around each of the articles, wherein the means for producing a tension in the composite web comprises a wrap roller in the upstream direction of the means for sealing the first and second webs, and a guide rod in the upstream direction of the wrap roller, the guide rod having an axially extending line that is in contact with the first web, and the wrap roller having an axially extending line that is in contact with the second web and that cooperates with the guide rod axially extending line to wrap the composite web in a reverse bend that produces the tension in the composite web; and c. means for cutting the first and second webs into individual products each consisting of a single selected article and of selected portions of the first and second webs. 16. A multi-web processing machine that continuously manufactures products comprising: a. means for continuously drawing in a downstream direction a composite web consisting of first and second webs and multiple discrete flexible articles held by friction between the first and second webs in a predetermined alignment and with predetermined spacinqs therebetween along the downstream direction; b. a rotary heat sealing system comprising: i. means for producing a tension in the composite web that maintains the predetermined alignment and spacing of the articles between the first and second webs; and ii. means tar sealing the first and second webs to each other around each of the articles, wherein the means for sealing the first and second webs comprises: a pair of transversely spaced side plates; an anvil rotatably mounted in the side plates; a heating die having spaced apart rails of a first diameter and in contact with the anvil at sele cted locations thereon, and a heat sealing grid between the rails and having a second diameter less than the first diameter and cooperating with the anvil to form a nip through which the composite web is drawn in the downstream direction, the heat sealing grid defining at least one pocket that receives the articles as the composite web is drawn in the downstream direction; and means for heating the heating die heat sealing grid an amount sufficient to seal the first and second webs to each other at areas that correspond to the heating die heat sealing grid, wherein: the nip between the beating die heat sealing grid and the anvil defines a nip plane; the means for producing a tension in the composite web comprises a guide rod in the upstream direction of the nip and having a first axially extending line at a first distance from the nip plate and a second axially extending line opposite the first axial line, and a wrap roller between the guide rod and the nip and having a first axially extending line at a second distance less than the first distance from the nip plane, the guide rod first axial line being spaced farther from the nip plane than the wrap roller first axially extending line; and the top and bottom webs are in contact with the guide rod first axial line and the wrap roller first axial line, respectively, such that the guide rod and the wrap roller cooperate to wrap the composite web in a reverse bend and thereby produce the tension on the composite web; and c. means for cutting the first and second webs into individual products each consisting of a single selected article and of selected portions of the first and second webs. 17. The multi-web processing machine of claim 16 wherein: a. the guide rod first axially extending line lies in the nip plane; and b. the wrap roller first axially extending line lies generally in the nip plane. 18. The multi-web processing machine of claim 16 wherein the guide rod is adjustable in directions parallel and perpendicular to the downstream direction to thereby compensate for any misalignment of the articles between the first and second webs. 19. The multi-web processing machine of claim 16 wherein the guide rod has a first predetermined diameter, and wherein the wrap roller has a second predetermined diameter that is larger than the first predetermined diameter. 20. A rotary heat sealing system comprising: a. a continuously rotating heating die having spaced apart circumferential rails of a first predetermined diameter, and a heat sealing grid between the rails, the heat sealing grid having at least two circumferential lands and at least one transverse land connecting the circumferential lands, the circumferential and transverse lands having a second diameter less than the first diameter, the circumferential and transverse lands cooperating to define at least one pocket; b. a continuously rotating anvil that rotates with the heating die, the anvil being in contact with the heating die rails and cooperating with the heating die heat sealing grid to form a nip through which a composite web consisting of top and bottom heat sealable webs pass in a downstream direction, flexible discrete articles held between the webs enter said at least one pocket in the heating die; and c. means for heating the heating die to a temperature sufficient to heat seal the top and bottom webs to each other, so that the webs are sealed to each other only in areas corresponding to the heating die heat sealing grid. 21. The rotary heat sealing system of claim 20 wherein the anvil is a cylinder having a uniform diameter at the nip with the heating die heat sealing grid. 22. The rotary heat sealing system of claim 20 further comprising a tensioning station in an upstream direction of the heating die and the anvil, the tensioning station producing a tension in the composite web prior to the top and bottom webs passing through the nip. 23. A rotary heat sealing system comprising: a. a continuously rotating heating die having spaced apart circumferential rails of a first predetermined diameter, and a heat sealing grid between the rails, the heat sealing grid having at least two circumferential lands and at least one transverse land connecting the circumferential lands, the circumferential and transverse lands having a second diameter less than the first diameter, the circumferential and transverse lands cooperating to define at least one pocket; b. a continuously rotating anvil that rotates with the heating die, the anvil being in contact with the heating die rails and cooperating with the heating die heat sealing grid to form a nip defining a nip plane through which a composite web consisting of top and bottom heat sealable webs pass in a downstream direction, flexible discrete articles held between the webs enter said at least one pocket in the heating die; and c. means for heating the heating die to a temperature sufficient to heat seal the top and bottom webs to each other; and d. a tensioning station in an upstream direction of the heating die and the anvil, the tensioning station producing a tension in the composite web prior to the top and bottom webs passing through the nip, wherein the tensioning station comprises: i. a wrap roller in the upstream direction of the nip and having an axially extending line at a first distance from the nip plane; and ii. a guide rod in the upstream direction of the wrap roller and having a first axially extending line at a second distance greater than the first distance from the nip plane, the composite web being in contact with the guide rod and wrap roller axially extending lines to wrap the composite web in a reverse bend prior to the top and bottom webs passing through the nip, so that the webs are sealed to each other only in areas corresponding to the heating die heat sealing grid. 24. The rotary heat sealing system of claim 23 wherein: a. the guide rod has a second axially extending line opposite the first axial line; and b. the guide rod second axially extending line and the wrap roller axially extending line each lie generally in the nip plane. 25. The rotary heat sealing system of claim 24 wherein the wrap roller has a first diameter, and wherein the guide rod has a second diameter less than the first diameter.