# US 9,822,581 B2 · Pressure compensated glass unit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,822,581 B2 - Document ID: US9822581B2 - Status: Granted - Kind: B2 - Application number: 14/905,150 - Filed: 2014-07-18 - Published: 2016-06-16 - Granted: 2017-11-21 - Earliest claimed: 2013-07-19 - Assignees: Litezone Technologies Inc. - Applicants: Litezone Technologies Inc. - Inventors: Gregory L. Clarahan - Web page: https://patentgrep.com/patent/US9822581B2 ## CPC - E06B 3/677: Evacuating or filling the gap between the panes {; Equilibration of inside and outside pressure}; Preventing condensation in the gap between the panes (by means of spacing elements E06B3/663); Cleaning the gap between the panes - E06B 3/66347: {with integral grooves or rabbets for holding the panes (E06B3/66366 takes precedence)} - E06B 3/66361: {with special structural provisions for holding drying agents, e.g. packed in special containers} - E06B 3/66366: {specially adapted for units comprising more than two panes or for attaching intermediate sheets} - E06B 3/667: Connectors therefor - E06B 3/6715: {specially adapted for increased thermal insulation or for controlled passage of light (E06B3/66323 takes precedence; coating of glass pains C03C17/00; devices or arrangements for controlling the intensity, colour, phase, polarisation or direction of light G02F1/00)} - E06B 7/02: for providing ventilation, e.g. through double windows; Arrangement of ventilation roses (airflow control members per se F24F13/08) - E06B 7/12: Measures preventing the formation of condensed water (double glazing E06B3/24 - E06B3/28 {and E06B3/677} ; heating arrangements specially adapted for transparent or reflecting areas H05B3/84) - E06B 7/14: Measures for draining-off condensed water or water leaking-in {frame members for draining off condensation water, throats at the bottom of a sash} - E06B 2003/6638: {with coatings} - E06B 2003/66395: {U-shape} - E06B: FIXED OR MOVABLE CLOSURES FOR OPENINGS IN BUILDINGS, VEHICLES, FENCES OR LIKE ENCLOSURES IN GENERAL, e.g. DOORS, WINDOWS, BLINDS, GATES (shades or blinds for greenhouses A01G9/22; curtains A47H; lids for car boots or bonnets B62D25/10; skylights E04B7/18; sunshades, awnings E04F10/00) ## Abstract A glass unit including a spacer, a front glass pane attached to a front side of the spacer, a back glass pane attached to a back side of the spacer, and a pressure equalization conduit defined by and within the spacer, wherein the pressure equalization conduit has a first end and a second end, wherein the pressure equalization conduit contains a desiccant and is in fluid communication with an exterior of the glass unit at a first end port adjacent to the first end and with an interior space of the glass unit at a second end port adjacent to the second end. The glass unit may further include one or more intermediate layers contained within the interior space and one or more floating suspension systems for supporting the intermediate layers. ## Claims ### Claim 1 A glass unit comprising: (a) a spacer defining a perimeter of the glass unit, wherein the spacer has a front side, a back side, an interior perimeter edge and an exterior perimeter edge; (b) a front glass pane attached to the front side of the spacer; (c) a back glass pane attached to the back side of the spacer, wherein the front glass pane and the back glass pane are maintained by the spacer in a spaced-apart parallel relationship which defines an interior space of the glass unit between the front glass pane and the back glass pane; and (d) a pressure equalization conduit defined by and within the spacer, wherein the pressure equalization conduit has a first end and a second end, wherein the pressure equalization conduit is in fluid communication with an exterior of the glass unit at a first end port which is adjacent to the first end of the pressure equalization conduit, wherein the pressure equalization conduit is in fluid communication with the interior space of the glass unit at a second end port which is adjacent to the second end of the pressure equalization conduit, wherein the pressure equalization conduit is continuous between the first end port and the second end Port so that a fluid can transfer through the pressure equalization conduit between the exterior of the glass unit and the interior space of the glass unit only at the first end port and the second end port, wherein the pressure equalization conduit is filled with a desiccant, and wherein the pressure equalization conduit extends within the spacer more than once around the perimeter of the glass unit so that the fluid is required to pass through the pressure equalization conduit more than once around the perimeter of the glass unit in order to transfer between the exterior of the glass unit and the interior space of the glass unit. ### Claim 2 (depends on 1) The glass unit as claimed in claim 1 wherein the first end port of the pressure equalization conduit is comprised of a single aperture extending between the pressure equalization conduit and the exterior of the glass unit. ### Claim 3 (depends on 1) The glass unit as claimed in claim 1 wherein the second end port of the pressure equalization conduit is comprised of a single aperture extending between the pressure equalization conduit and the interior space of the glass unit. ### Claim 4 (depends on 1) The glass unit as claimed in claim 1 wherein the second end port of the pressure equalization conduit is comprised of a plurality of apertures extending between the pressure equalization conduit and the interior space of the glass unit. ### Claim 5 (depends on 1) The glass unit as claimed in claim 1 wherein the spacer defines therein a plurality of channels extending around the perimeter of the glass unit which are connected together in a series configuration, and wherein the plurality of channels provide the pressure equalization conduit. ### Claim 6 (depends on 5) The glass unit as claimed in claim 5 wherein the spacer is comprised of a crossover section for connecting the plurality of channels together in the series configuration. ### Claim 7 (depends on 1) The glass unit as claimed in claim 1, further comprising a front seal around the perimeter of the glass unit for providing a seal between the spacer and the front glass pane, and further comprising a back seal around the perimeter of the glass unit for providing a seal between the spacer and the back glass pane. ### Claim 8 (depends on 1) The glass unit as claimed in claim 1, further comprising: (a) an intermediate layer contained within the interior space of the glass unit, wherein the intermediate layer has a perimeter; and (b) a floating suspension system associated with the intermediate layer and the spacer, wherein the perimeter of the intermediate layer is supported by the spacer with the floating suspension system so that the intermediate layer is in a spaced-apart parallel relationship with the front glass pane and the back glass pane and so that the intermediate layer is capable of moving biaxially within the interior space of the glass unit. ### Claim 9 (depends on 8) The glass unit as claimed in claim 8 wherein the intermediate layer is a film layer and wherein the floating suspension system is comprised of: (a) a film bar attached to the film layer around the perimeter of the film layer; (b) a film slot defined by the spacer around the interior perimeter edge of the spacer, for receiving the film layer therein; (c) a suspension chamber defined within the spacer around the perimeter of the glass unit, wherein the suspension chamber is in communication with the film slot, for receiving the film bar therein; and (d) a biasing mechanism for biasing the film bar away from the interior perimeter edge of the spacer. ### Claim 10 (depends on 9) The glass unit as claimed in claim 9 wherein the film bar is comprised of a plurality of film bar members arranged around the perimeter of the film layer. ### Claim 11 (depends on 10) The glass unit as claimed in claim 10 wherein the plurality of film bar members are arranged around the perimeter of the film layer such that gaps are provided between adjacent film bar members. ### Claim 12 (depends on 8) The glass unit as claimed in claim 8 wherein the intermediate layer is a glass lite and wherein the floating suspension system is comprised of a lite pocket defined by the spacer around the interior perimeter edge of the spacer, for receiving the perimeter of the glass lite therein. ### Claim 13 (depends on 12) The glass unit as claimed in claim 12 wherein the floating suspension system is configured to allow a fluid contained within the interior space of the glass unit to pass around the perimeter of the glass lite by passing through the lite pocket. ### Claim 14 (depends on 12) The glass unit as claimed in claim 12 wherein the floating suspension system is further comprised of a biasing mechanism for biasing the perimeter of the glass lite toward the interior perimeter edge of the spacer. ### Claim 15 (depends on 14) The glass unit as claimed in claim 14 wherein the biasing mechanism is comprised of a resilient material arranged within the lite pocket around at least a portion of the perimeter of the glass unit. ### Claim 16 (depends on 9) The glass unit as claimed in claim 9 wherein the floating suspension system is configured to allow a fluid contained within the interior space of the glass unit to pass around the perimeter of the film layer by passing through the film slot and the suspension chamber. ### Claim 17 (depends on 9) The glass unit as claimed in claim 9 wherein the film bar is comprised of a film bar engagement surface, wherein the suspension chamber is comprised of a chamber engagement surface, and wherein the biasing mechanism is positioned in the suspension chamber between the film bar engagement surface and the chamber engagement surface. ### Claim 18 (depends on 17) The glass unit as claimed in claim 17 wherein the biasing mechanism is comprised of a plurality of springs arranged within the suspension chamber around the perimeter of the glass unit. ### Claim 19 (depends on 1) The glass unit as claimed in claim 1, further comprising: (a) a plurality of intermediate layers contained within the interior space of the glass unit, wherein each of the intermediate layers has a perimeter; (b) a plurality of floating suspension systems, each associated with one of the plurality of intermediate layers and the spacer, wherein the perimeters of the intermediate layers are supported by the spacer with the floating suspension systems so that the intermediate layers are in a spaced-apart parallel relationship with the front glass pane and the back glass pane and so that the intermediate layers are capable of moving biaxially within the interior space of the glass unit. ### Claim 20 (depends on 19) The glass unit as claimed in claim 19 wherein at least one of the plurality of intermediate layers is a glass lite and wherein each of the floating suspension systems associated with one of the glass lites is comprised of a lite pocket defined by the spacer around the interior perimeter edge of the spacer, for receiving the perimeter of the one of the glass lites therein. ### Claim 21 (depends on 20) The glass unit as claimed in claim 20 wherein each of the floating suspension systems associated with one of the glass lites is configured to allow a fluid contained within the interior space of the glass unit to pass around the perimeter of the associated glass lite by passing through the lite pocket. ### Claim 22 (depends on 20) The glass unit as claimed in claim 20 wherein each of the floating suspension systems associated with one of the glass lites is further comprised of a biasing mechanism for biasing the perimeter of the associated glass lite toward the interior perimeter edge of the spacer. ### Claim 23 (depends on 22) The glass unit as claimed in claim 22 wherein the biasing mechanism is comprised of a resilient material arranged within the lite pocket around at least a portion of the perimeter of the glass unit. ### Claim 24 (depends on 19) The glass unit as claimed in claim 19 wherein at least one of the plurality of intermediate layers is a film layer and wherein each of the floating suspension systems associated with one of the film layers is comprised of: (a) a film bar attached to one of the film layers around the perimeter of the one of the film layers; (b) a film slot defined by the spacer around the interior perimeter edge of the spacer, for receiving the one of the film layers therein; (c) a suspension chamber defined within the spacer around the perimeter of the glass unit, wherein the suspension chamber is in communication with the film slot, for receiving the film bar therein; and (d) a biasing mechanism for biasing the film bar away from the interior perimeter edge of the spacer. ### Claim 25 (depends on 24) The glass unit as claimed in claim 24 wherein each of the floating suspension systems associated with one of the film layers is configured to allow a fluid contained within the interior space of the glass unit to pass around the perimeter of the associated film layer by passing through the film slot and the suspension chamber. ### Claim 26 (depends on 24) The glass unit as claimed in claim 24 wherein the film bar is comprised of a film bar engagement surface, wherein the suspension chamber is comprised of a chamber engagement surface, and wherein the biasing mechanism is positioned in the suspension chamber between the film bar engagement surface and the chamber engagement surface. ### Claim 27 (depends on 26) The glass unit as claimed in claim 26 wherein the biasing mechanism is comprised of a plurality of springs arranged within the suspension chamber around the perimeter of the glass unit. ### Claim 28 (depends on 24) The glass unit as claimed in claim 24 wherein the film bar is comprised of a plurality of film bar members arranged around the perimeter of the film layer. ### Claim 29 (depends on 28) The glass unit as claimed in claim 28 wherein the plurality of film bar members are arranged around the perimeter of the film layer such that gaps are provided between adjacent film bar members. ### Claim 30 (depends on 1) The glass unit as claimed in claim 1 wherein the perimeter of the glass unit is a rectangular perimeter, wherein the spacer is comprised of four spacer side members which are connected together to define the rectangular perimeter. ### Claim 31 (depends on 30) The glass unit as claimed in claim 30 wherein the spacer is further comprised of four spacer corner members for connecting the spacer side members together. ### Claim 32 (depends on 31) The glass unit as claimed in claim 31 wherein the spacer defines a plurality of channels extending around the perimeter of the glass unit which are connected together in a series configuration, and wherein the plurality of channels provide the pressure equalization conduit. ### Claim 33 (depends on 32) The glass unit as claimed in claim 32 wherein the spacer is further comprised of a crossover section for connecting the plurality of channels together in the series configuration, and wherein one of the spacer corner members is comprised of the crossover section. ### Claim 34 (depends on 30) The glass unit as claimed in claim 30, further comprising a front seal around the perimeter of the glass unit for providing a seal between the spacer and the front glass pane, and further comprising a back seal around the perimeter of the glass unit for providing a seal between the spacer and the back glass pane. ### Claim 35 (depends on 1) The glass unit as claimed in claim 1, further comprising: (e) one or more intermediate layers contained within the interior space of the glass unit, wherein each of the one or more intermediate layers has a perimeter; and (f) one or more floating suspension systems, each associated with one intermediate layer and the spacer, wherein the perimeters of the one or more intermediate layers are supported by the spacer with the one or more floating suspension systems so that the one or more intermediate layers are in a spaced-apart parallel relationship with the front glass pane and the back glass pane and so that the one or more intermediate layers are capable of moving biaxially within the interior space of the glass unit. ### Claim 36 (depends on 35) The glass unit as claimed in claim 35, further comprising a front seal around the perimeter of the glass unit for providing a seal between the spacer and the front glass pane, and further comprising a back seal around the perimeter of the glass unit for providing a seal between the spacer and the back glass pane. ### Claim 37 (depends on 35) The glass unit as claimed in claim 35 wherein at least one intermediate layer is a film layer and wherein the at least one floating suspension system associated with the at least one film layer is comprised of: (a) a film bar attached to the film layer around the perimeter of the film layer; (b) a film slot defined by the spacer around the interior perimeter edge of the spacer, for receiving the film layer therein; (c) a suspension chamber defined within the spacer around the perimeter of the glass unit, wherein the suspension chamber is in communication with the film slot, for receiving the film bar therein; and (d) a biasing mechanism for biasing the film bar away from the interior perimeter edge of the spacer. ### Claim 38 (depends on 37) The glass unit as claimed in claim 37 wherein the at least one floating suspension system associated with the at least one film layer is configured to allow a fluid contained within the interior space of the glass unit to pass around the perimeter of the film layer by passing through the film slot and the suspension chamber. ### Claim 39 (depends on 37) The glass unit as claimed in claim 37 wherein the film bar is comprised of a film bar engagement surface, wherein the suspension chamber is comprised of a chamber engagement surface, and wherein the biasing mechanism is positioned in the suspension chamber between the film bar engagement surface and the chamber engagement surface. ### Claim 40 (depends on 39) The glass unit as claimed in claim 39 wherein the biasing mechanism is comprised of a plurality of springs arranged within the suspension chamber around the perimeter of the glass unit. ### Claim 41 (depends on 37) The glass unit as claimed in claim 37 wherein the film bar is comprised of a plurality of film bar members arranged around the perimeter of the film layer. ### Claim 42 (depends on 41) The glass unit as claimed in claim 41 wherein the plurality of film bar members are arranged around the perimeter of the film layer such that gaps are provided between adjacent film bar members. ### Claim 43 (depends on 35) The glass unit as claimed in claim 35 wherein at least one intermediate layer is a glass lite and wherein the at least one floating suspension system associated with the at least one glass lite is comprised of a lite pocket defined by the spacer around the interior perimeter edge of the spacer, for receiving the perimeter of the glass lite therein. ### Claim 44 (depends on 43) The glass unit as claimed in claim 43 wherein the at least one floating suspension system associated with the at least one glass lite is configured to allow a fluid contained within the interior space of the glass unit to pass around the perimeter of the glass lite by passing through the lite pocket. ### Claim 45 (depends on 43) The glass unit as claimed in claim 43 wherein the at least one floating suspension system associated with the at least one glass lite is further comprised of a biasing mechanism for biasing the perimeter of the associated glass lite toward the interior perimeter edge of the spacer. ### Claim 46 (depends on 45) The glass unit as claimed in claim 45 wherein the biasing mechanism is comprised of a resilient material arranged within the lite pocket around at least a portion of the perimeter of the glass unit. ### Claim 47 A glass unit comprising: (a) a spacer defining a perimeter of the glass unit, wherein the spacer has a front side, a back side, an interior perimeter edge and an exterior perimeter edge; (b) a front glass pane attached to the front side of the spacer; (c) a back glass pane attached to the back side of the spacer, wherein the front glass pane and the back glass pane are maintained by the spacer in a spaced-apart parallel relationship which defines an interior space of the glass unit between the front glass pane and the back glass pane; (d) a pressure equalization conduit defined by and within the spacer, wherein the pressure equalization conduit has a first end and a second end, wherein the pressure equalization conduit is in fluid communication with an exterior of the glass unit at a first end port which is adjacent to the first end of the pressure equalization conduit, wherein the pressure equalization conduit is in fluid communication with the interior space of the glass unit at a second end port which is adjacent to the second end of the pressure equalization conduit, wherein the pressure equalization conduit is continuous between the first end port and the second end port so that a fluid can transfer through the pressure equalization conduit between the exterior of the glass unit and the interior space of the glass unit only at the first end port and the second end port, and wherein the pressure equalization conduit is filled with a desiccant; (e) an intermediate layer contained within the interior space of the glass unit, wherein the intermediate layer has a perimeter; and (f) a floating suspension system associated with the intermediate layer and the spacer, wherein the perimeter of the intermediate layer is supported by the spacer with the floating suspension system so that the intermediate layer is in a spaced-apart parallel relationship with the front glass pane and the back glass pane and so that the intermediate layer is capable of moving biaxially within the interior space of the glass unit, wherein the intermediate layer is a glass lite and wherein the floating suspension system is comprised of a lite pocket defined by the spacer around the interior perimeter edge of the spacer, for receiving the perimeter of the glass lite therein. ### Claim 48 (depends on 47) The glass unit as claimed in claim 47 wherein the floating suspension system is configured to allow a fluid contained within the interior space of the glass unit to pass around the perimeter of the glass lite by passing through the lite pocket. ### Claim 49 (depends on 47) The glass unit as claimed in claim 47 wherein the floating suspension system is further comprised of a biasing mechanism for biasing the perimeter of the glass lite toward the interior perimeter edge of the spacer. ### Claim 50 (depends on 49) The glass unit as claimed in claim 49 wherein the biasing mechanism is comprised of a resilient material arranged within the lite pocket around at least a portion of the perimeter of the glass unit. ### Claim 51 A glass unit comprising: (a) a spacer defining a perimeter of the glass unit, wherein the spacer has a front side, a back side, an interior perimeter edge and an exterior perimeter edge; (b) a front glass pane attached to the front side of the spacer; (c) a back glass pane attached to the back side of the spacer, wherein the front glass pane and the back glass pane are maintained by the spacer in a spaced-apart parallel relationship which defines an interior space of the glass unit between the front glass pane and the back glass pane; (d) a pressure equalization conduit defined by and within the spacer, wherein the pressure equalization conduit has a first end and a second end, wherein the pressure equalization conduit is in fluid communication with an exterior of the glass unit at a first end port which is adjacent to the first end of the pressure equalization conduit, wherein the pressure equalization conduit is in fluid communication with the interior space of the glass unit at a second end port which is adjacent to the second end of the pressure equalization conduit, wherein the pressure equalization conduit is continuous between the first end port and the second end port so that a fluid can transfer through the pressure equalization conduit between the exterior of the glass unit and the interior space of the glass unit only at the first end port and the second end port, and wherein the pressure equalization conduit is filled with a desiccant; (e) a plurality of intermediate layers contained within the interior space of the glass unit, wherein each of the intermediate layers has a perimeter; and (f) a plurality of floating suspension systems, each associated with one of the plurality of intermediate layers and the spacer, wherein the perimeters of the intermediate layers are supported by the spacer with the floating suspension systems so that the intermediate layers are in a spaced-apart parallel relationship with the front glass pane and the back glass pane and so that the intermediate layers are capable of moving biaxially within the interior space of the glass unit, wherein at least one of the plurality of intermediate layers is a glass lite and wherein each of the floating suspension systems associated with one of the glass lites is comprised of a lite pocket defined by the spacer around the interior perimeter edge of the spacer, for receiving the perimeter of the one of the glass lites therein. ### Claim 52 (depends on 51) The glass unit as claimed in claim 51 wherein each of the floating suspension systems associated with one of the glass lites is configured to allow a fluid contained within the interior space of the glass unit to pass around the perimeter of the associated glass lite by passing through the lite pocket. ### Claim 53 (depends on 51) The glass unit as claimed in claim 51 wherein each of the floating suspension systems associated with one of the glass lites is further comprised of a biasing mechanism for biasing the perimeter of the associated glass lite toward the interior perimeter edge of the spacer. ### Claim 54 (depends on 53) The glass unit as claimed in claim 53 wherein the biasing mechanism is comprised of a resilient material arranged within the lite pocket around at least a portion of the perimeter of the glass unit. ### Claim 55 A glass unit comprising: (a) a spacer defining a perimeter of the glass unit, wherein the spacer has a front side, a back side, an interior perimeter edge and an exterior perimeter edge; (b) a front glass pane attached to the front side of the spacer; (c) a back glass pane attached to the back side of the spacer, wherein the front glass pane and the back glass pane are maintained by the spacer in a spaced-apart parallel relationship which defines an interior space of the glass unit between the front glass pane and the back glass pane; (d) a pressure equalization conduit defined by and within the spacer, wherein the pressure equalization conduit has a first end and a second end, wherein the pressure equalization conduit is in fluid communication with an exterior of the glass unit at a first end port which is adjacent to the first end of the pressure equalization conduit, wherein the pressure equalization conduit is in fluid communication with the interior space of the glass unit at a second end port which is adjacent to the second end of the pressure equalization conduit, and wherein the pressure equalization conduit is filled with a desiccant; (e) one or more intermediate layers contained within the interior space of the glass unit, wherein each of the one or more intermediate layers has a perimeter; and (f) one or more floating suspension systems, each associated with one intermediate layer and the spacer, wherein the perimeters of the one or more intermediate layers are supported by the spacer with the one or more floating suspension systems so that the one or more intermediate layers are in a spaced-apart parallel relationship with the front glass pane and the back glass pane and so that the one or more intermediate layers are capable of moving biaxially within the interior space of the glass unit, wherein at least one intermediate layer is a glass lite and wherein the at least one floating suspension system associated with the at least one glass lite is comprised of a lite pocket defined by the spacer around the interior perimeter edge of the spacer, for receiving the perimeter of the glass lite therein. ### Claim 56 (depends on 55) The glass unit as claimed in claim 55 wherein the at least one floating suspension system associated with the at least one glass lite is configured to allow a fluid contained within the interior space of the glass unit to pass around the perimeter of the glass lite by passing through the lite pocket. ### Claim 57 (depends on 55) The glass unit as claimed in claim 55 wherein the at least one floating suspension system associated with the at least one glass lite is further comprised of a biasing mechanism for biasing the perimeter of the associated glass lite toward the interior perimeter edge of the spacer. ### Claim 58 (depends on 57) The glass unit as claimed in claim 57 wherein the biasing mechanism is comprised of a resilient material arranged within the lite pocket around at least a portion of the perimeter of the glass unit. ### Claim 59 (depends on 55) The glass unit as claimed in claim 55 wherein the pressure equalization conduit is continuous between the first end port and the second end port so that a fluid can transfer through the pressure equalization conduit between the exterior of the glass unit and the interior space of the glass unit only at the first end port and the second end port. ### Claim 60 (depends on 59) The glass unit as claimed in claim 59 wherein the first end port of the pressure equalization conduit is comprised of a single aperture extending between the pressure equalization conduit and the exterior of the glass unit. ### Claim 61 (depends on 59) The glass unit as claimed in claim 59 wherein the second end port of the pressure equalization conduit is comprised of a single aperture extending between the pressure equalization conduit and the interior space of the glass unit. ### Claim 62 (depends on 59) The glass unit as claimed in claim 59 wherein the second end port of the pressure equalization conduit is comprised of a plurality of apertures extending between the pressure equalization conduit and the interior space of the glass unit. ### Claim 63 (depends on 59) The glass unit as claimed in claim 59 wherein the pressure equalization conduit extends within the spacer around at least a portion of the perimeter of the glass unit. ### Claim 64 (depends on 59) The glass unit as claimed in claim 59 wherein the pressure equalization conduit extends within the spacer at least once around the perimeter of the glass unit. ### Claim 65 (depends on 59) The glass unit as claimed in claim 59 wherein the pressure equalization conduit extends within the spacer more than once around the perimeter of the glass unit so that the fluid is required to pass through the pressure equalization conduit more than once around the perimeter of the glass unit in order to transfer between the exterior of the glass unit and the interior space of the glass unit. ### Claim 66 (depends on 65) The glass unit as claimed in claim 65 wherein the spacer defines therein a plurality of channels extending around the perimeter of the glass unit which are connected together in a series configuration, and wherein the plurality of channels provide the pressure equalization conduit. ### Claim 67 (depends on 66) The glass unit as claimed in claim 66 wherein the spacer is comprised of a crossover section for connecting the plurality of channels together in the series configuration. ### Claim 68 (depends on 59) The glass unit as claimed in claim 59, further comprising a front seal around the perimeter of the glass unit for providing a seal between the spacer and the front glass pane, and further comprising a back seal around the perimeter of the glass unit for providing a seal between the spacer and the back glass pane.