Temperature compensated fill valve/pressure switch
First Claim
1. A device for monitoring fluid pressure within a container, the device comprising:
- a body adapted to be positioned adjacent a wall of the container;
switch means disposed within said body, and operative to monitor the fluid pressure within the container and shift from a first state to a second state when the fluid pressure falls below a selected level; and
means operative to effect a preselectable temperature compensation characteristic for said device, said compensation means including a sealed prepressurized cavity defined entirely by said body and a compliant wall member operative to substantially vary the volume of said cavity as a function of cavity pressure and container fluid pressure, and engaging said switch means to vary said selected level.
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Accused Products
Abstract
A device for filling a pneumatic tire and sensing the air pressure therein has a check valve disposed within a valve stem and a pressure sensing switch which is temperature compensated to adjust for air pressure changes within the tire due to changes in ambient temperature. Substantially perfect compensation can be achieved, within a limited range of operation, whereby the set point pressure versus temperature characteristic will track with the related tire pressure versus temperature characteristic. A manual set point adjustment feature is provided whereby the switch can be calibrated after it is assembled within a wheel and pneumatic tire. The switch can also be employed independently of, as well as in conjunction with, the check valve.
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Citations
31 Claims
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1. A device for monitoring fluid pressure within a container, the device comprising:
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a body adapted to be positioned adjacent a wall of the container; switch means disposed within said body, and operative to monitor the fluid pressure within the container and shift from a first state to a second state when the fluid pressure falls below a selected level; and means operative to effect a preselectable temperature compensation characteristic for said device, said compensation means including a sealed prepressurized cavity defined entirely by said body and a compliant wall member operative to substantially vary the volume of said cavity as a function of cavity pressure and container fluid pressure, and engaging said switch means to vary said selected level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device for pressurizing a container and monitoring fluid pressure levels within the container, the device comprising:
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a body defining an inlet passage and adapted to be positioned in an aperture in a wall of the container; valve means removably disposed within said passage and operative to selectively pass fluid therethrough; switch means disposed within said body, and operative to monitor the fluid pressure within the container and to shift from a first state to a second state when the fluid pressure falls below a selected level; compensation means operative to vary said selected level as a function of fluid temperature; and adjustment means disposed within said body and accessible through said inlet passage when said device is installed within an associated container, said adjustment means being operable to manually vary said selected level. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A device for pressurizing a container and monitoring fluid pressure levels within said container, the device comprising:
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a body defining a switch portion adapted for insulative mounting within said container and a valve stem portion, projecting outwardly from said switch portion, said valve stem portion defining an inlet passage; a check valve removably disposed within said inlet passage; switch means disposed within said switch portion and operative to shift between a first state and a second state as a function of fluid pressure within said container, said switch means comprising first and second terminals which are electrically open in said first state and electrically connected in said second state; compensation means operative to vary the pressure at which said switch means shifts between states as a function of fluid temperature; and adjustment means disposed within said valve stem portion and accessible through said inlet passage when said device is installed within an associated container, said adjustment means being operable to manually vary said switch means shift pressure. - View Dependent Claims (24)
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25. A fill valve-temperature commpensated pressure device including a switch in combination with a pneumatic tire and associated mating wheel, comprising:
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a body insulatively mounted within said wheel and including a valve stem portion projecting outwardly therefrom; a check valve removably disposed within an inlet passage defined by said valve stem portion operative to admit air into said tire and prevent the escape of air from said tire; a switch disposed within said body and comprising a pair of electrical contacts which open and close as a function of the air pressure within said tire; temperature compensation means disposed within said body and operative to displace at least one of said contacts with respect to another said contact as a function of air temperature within said tire to determine a transition pressure at which said contacts open and close, said transition pressure varying as a function of air temperature; and set-point adjustment means disposed within said valve stem portion and accessible through said inlet passage when said valve-switch device is installed within an associated pneumatic tire and wheel, said adjustment means being operable to manually vary said transition pressure. - View Dependent Claims (26, 27, 28, 29, 30, 31)
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Specification