Negative pressure conditioning device with low pressure cut-off
First Claim
Patent Images
1. A gas valve assembly comprising:
- a gas valve configured to provide gas to a fuel burning appliance, the gas valve comprising a first port and a second port;
a signal conditioning device comprising a first fluid path including a first inlet and a first outlet and a second fluid path including a second inlet and a second outlet; and
a pressure switch having a first pressure switch inlet, a first pressure switch outlet, a second pressure switch inlet and a second pressure switch outlet;
wherein the first outlet is in fluid communication with the first pressure switch inlet, the second outlet is in fluid communication with the second pressure switch inlet, the first pressure switch outlet is in fluid communication with the first port of the gas valve and the second pressure switch outlet is in fluid communication with the second port of the gas valve.
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Abstract
A pneumatic signal conditioning device may have a first fluid path and a second fluid path. The first fluid path includes a first inlet and a first outlet, and is configured such that the first outlet provides a first conditioned signal representing a pressure at the first inlet. Similarly, the second fluid path is configured such that the second outlet provides a second conditioned signal representing a pressure at the second inlet. A pressure switch may be disposed in fluid communication with the first fluid path and the second fluid path such that the first fluid path and the second fluid path pass through the pressure switch.
67 Citations
16 Claims
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1. A gas valve assembly comprising:
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a gas valve configured to provide gas to a fuel burning appliance, the gas valve comprising a first port and a second port; a signal conditioning device comprising a first fluid path including a first inlet and a first outlet and a second fluid path including a second inlet and a second outlet; and a pressure switch having a first pressure switch inlet, a first pressure switch outlet, a second pressure switch inlet and a second pressure switch outlet; wherein the first outlet is in fluid communication with the first pressure switch inlet, the second outlet is in fluid communication with the second pressure switch inlet, the first pressure switch outlet is in fluid communication with the first port of the gas valve and the second pressure switch outlet is in fluid communication with the second port of the gas valve. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A forced-air furnace comprising:
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a heat exchanger having an upstream port and a downstream port; a burner configured to burn fuel and provide combustion products to the heat exchanger; a gas valve configured to provide fuel to the burner, the gas valve comprising a first pressure port and a second pressure port; and a pneumatic signal conditioning device comprising; a first fluid path comprising a first inlet and a first outlet, the first fluid path configured such that the first outlet provides a first conditioned signal representing a pressure at the first inlet; a second fluid path comprising a second inlet and a second outlet, the second fluid path configured such that the second outlet provides a second conditioned signal representing a pressure at the second inlet; and a pressure switch disposed in fluid communication with the first fluid path and the second fluid path such that the first fluid path extends through a first side of the pressure switch and the second fluid path extends through a second side of the pressure switch; wherein the first inlet is in fluid communication with the upstream port, the second inlet is in fluid communication with the downstream port, the first outlet is in fluid communication with the first pressure port and the second outlet is in fluid communication with the second pressure port. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A pneumatic signal conditioning device for providing conditioned pneumatic control signals to a pneumatically controlled gas valve comprising:
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a housing having a first inlet, a second inlet, a first outlet and a second outlet; the housing defining a first fluid path that extends between the first inlet and the first outlet; the housing further defining a second fluid path that extends between the second inlet and the second outlet; the housing further defining a third fluid path that extends between the first fluid path and the second fluid path; the first fluid path, the second fluid path and the third fluid path having dimensions that produce a first conditioned signal at the first outlet representing a pressure at the first inlet and a second conditioned signal at the second outlet representing a pressure at the second inlet; a pressure switch having a first pressure switch inlet, a second pressure switch inlet, a first pressure switch outlet and a second pressure switch outlet, wherein the first pressure switch inlet is in fluid communication with the first pressure switch outlet and the second pressure switch inlet is in fluid communication with the second pressure switch outlet; the first pressure switch inlet being in fluid communication with the first outlet of the housing and the second pressure switch inlet being in fluid communication with the second outlet of the housing; wherein the first pressure switch outlet and the second pressure switch outlet are configured to provide conditioned pneumatic control signals to a pneumatically controlled gas valve; and wherein the pressure switch is configured to provide a control signal that can disable a pneumatically controlled gas valve when a minimum pressure differential is detected between a pressure related to the pressure at the first pressure switch inlet of the pressure switch and a pressure related to the pressure at the second pressure switch inlet of the pressure switch.
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16. A gas valve assembly comprising:
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a modulating gas valve configured to provide gas to a fuel burning appliance, the gas valve comprising a first control port and a second control port; a signal conditioning device having a first fluid path including a first inlet and a first outlet and a second fluid path including a second inlet and a second outlet; a pressure switch electrically wired in series between a power source and the modulating gas valve, the pressure switch having a first pressure switch inlet in fluid communication with the first outlet of the signal conditioning device, a first pressure switch outlet in fluid communication with the first control port of the gas valve, a second pressure switch inlet in fluid communication with the second outlet of the signal conditioning device, and a second pressure switch outlet in fluid communication with the second port of the gas valve; and wherein the modulating gas valve regulates gas flow to a fuel burning appliance in response to a pressure difference between the first port and the second port of the gas valve, and wherein if the pressure difference drops below a predetermined level, the pressure switch opens to prevent electrical power from being delivered from the power source to the modulating gas valve.
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Specification