Microwave-based point liquid level monitoring system

A system for monitoring a point liquid level comprising:

• a liquid level device having liquid in a cavity thereof and having a window which is transparent to microwaves and normally allows visual observation of the liquid in the liquid level device,
• a microwave transmitter mounted to the liquid level device at a predetermined level to direct a microwave signal through the window and into the cavity in the device, and
• a receiver mounted to the liquid level device at the predetermined level to receive the microwave signal through the window, such that the microwave signal from the transmitter is reflected off a surface on the liquid level device opposite from the window and directed back through the window to be received by the receiver, the microwave signal being attenuated between said transmitter and said receiver when liquid is present in the cavity at or above the predetermined level and not attenuated between said transmitter and receiver when liquid is absent in the cavity at the predetermined level, thereby to provide a continuous means of monitoring whether or not liquid is present at such predetermined level based upon whether or not the microwave signal is attenuated when received, and
• wherein said transmitter and receiver are included within a sensor, and said sensor has a base with at least one adjustment screw and a neck portion, said neck portion being located within an aperture formed in the liquid level device and adapted to direct the microwave signal through the microwave transparent window, and said at least one adjustment screw being located adjacent an outer surface of the liquid level device and being adjustable to removably mount said sensor to the liquid level device.

A system for monitoring a point liquid level comprising:

• a liquid level device having liquid in a cavity thereof and having a window which is transparent to microwaves and normally allows visual observation of the liquid in the liquid level device,
• a microwave transmitter mounted to the liquid level device at a predetermined level to direct a microwave signal through the window and into the cavity in the device, and
• a receiver mounted to the liquid level device at the predetermined level to receive the microwave signal through the window, such that the microwave signal from the transmitter is reflected off a surface on the liquid level device opposite from the window and directed back through the window to be received by the receiver, the microwave signal being attenuated between said transmitter and said receiver when liquid is present in the cavity at or above the predetermined level and not attenuated between said transmitter and receiver when liquid is absent in the cavity at the predetermined level, thereby to provide a continuous means of monitoring whether or not liquid is present at such predetermined level based upon whether or not the microwave signal is attenuated when received, and
• wherein said transmitter and receiver are included within a sensor, and said sensor includes a clamp assembly having a pivotable clamp plate and a neck portion, said neck portion being located within an aperture formed in the liquid level device, and said pivotable clamp plate being located adjacent an outer surface of the liquid level device and being pivotally adjustable to removably mount said sensor to the liquid level device.

A sensor designed to be mounted at a preselected level to a liquid level device, the liquid level device having a window which is substantially transparent to microwaves and normally allows visual observation of the liquid in the liquid level device, said sensor comprising:

• a first waveguide having a configuration to direct a microwave signal through the window and into a cavity in the liquid level device,
• a reflector located on a side of said cavity opposite said window for reflecting said microwave signal,
• a second waveguide having a configuration to collect the reflected microwave signal received through the window in the liquid level device, the microwave signal being attenuated between said first and second waveguides if liquid is present in the liquid level device at or above the preselected level, and not attenuated if liquid is absent at the preselected level,
• a microwave transmitter to transmit the microwave signal through said first waveguide, and
• a microwave receiver to receive the reflected microwave signal through said second waveguide, Said transmitter and said receiver contained within a single housing, thereby to provide a continuous means of monitoring whether or not liquid is present at such predetermined level based upon whether or not the microwave signal is attenuated when received.

A sensor designed to be mounted at a preselected level to a liquid level device, said sensor comprising:

• a first waveguide having a configuration to direct a microwave signal through a window substantially transparent to microwaves and into a cavity in the liquid level device, the microwave signal from the transmitter being reflected off an internal surface in the liquid level device and directed back through the window, and
• a second waveguide having a configuration to collect the reflected microwave signal received through the window in the liquid level device, the microwave signal being attenuated between said first and second waveguides if liquid is present in the liquid level device at or above the preselected level, and not attenuated if liquid is absent at the preselected level,
• a microwave transmitter to transmit the microwave signal through said first waveguide, and
• a microwave receiver to receive the reflected microwave signal through said second waveguide,
• said sensor having a base with adjustment screws and a neck portion, said adjustment screws being located adjacent an outer surface of the liquid level device and said neck portion being located within an aperture formed in the liquid level device and adapted to direct the microwave signal through the substantially microwave-transparent window, said screws being adjustable to removably mount said sensor to the liquid level device.

A sensor designed to be mounted at a preselected level to a liquid level device, said sensor comprising:

• a first waveguide having a configuration to direct a microwave signal through a window substantially transparent to microwaves and into a cavity in the liquid level device, the microwave signal from the transmitter being reflected off an internal surface in the liquid level device and directed back through the window, and
• a second waveguide having a configuration to collect the reflected microwave signal received through the window in the liquid level device, the microwave signal being attenuated between said first and second waveguides if liquid is present in the liquid level device at or above the preselected level, and not attenuated if liquid is absent at the preselected level,
• a microwave transmitter to transmit the microwave signal through said first waveguide, and
• a microwave receiver to receive the reflected microwave signal through said second waveguide,
• said sensor including a clamp assembly having a pivotable clamp plate and a neck portion, said neck portion being located within an aperture formed in the liquid level device, and said clamp plate being located adjacent an outer surface of the liquid level device and being pivotably adjustable to removably mount said sensor to the liquid level device.