Expansion valve position detection in refrigeration system
AssigneeHill Phoenix, Inc.
InventorsNaresh Kumar Krishnamoorthy, Shobin Balakrishnan
Life of this patent
Estimating the term…
Abstract
A refrigerated display case having a housing defining a temperature controlled space and a refrigeration system coupled to the housing is provided. The refrigeration system is configured to be operable to affect a temperature of the temperature controlled space. The refrigeration system includes an actuator, a controller, and a sensor. The controller is configured to continuously update a stored position of the actuator based on measurement of an electric current provided to the actuator, retrieve the stored position after a power failure, and restart control based on the stored position of the actuator. The sensor is configured to communicate with the controller.
Claims20
A refrigerated display case comprising:
- a housing defining a temperature controlled space;
- a refrigeration system coupled to the housing and operable to affect a temperature of the temperature controlled space, and comprising:
- an actuator configured to operate an expansion valve, the actuator comprising a stepper motor such that the expansion valve is selectively operated by the stepper motor to a plurality of discrete positions;
- a controller configured to:
- update a stored position of the actuator based on measurement of an electric current provided to the actuator;
- retrieve the stored position after a power failure;
- restart control based on the stored position of the actuator;
- send a signal that comprises a current spike to the stepper motor to selectively change a position of the plurality of discrete positions of the actuator;
- selectively provide the electric current provided to the actuator;
- detect a magnitude change in the electric current provided to the actuator;
- based on the detected magnitude change, determine a particular position of the plurality of discrete positions of the actuator;
- and
- store the particular determined position of the plurality of discrete positions of the actuator.
A method of monitoring valve deflection in a refrigeration system comprising:
- selectively operating an actuator that comprises a stepper motor, the actuator configured to move an expansion valve to a plurality of discrete positions;
- detecting a magnitude change in at least one electric property provided to the actuator;
- subsequent to the detected magnitude change, sensing a current spike of the stepper motor;
- determining a magnitude of the current spike;
- based on the detected magnitude change and magnitude of the current spike, determining a particular position of a plurality of positions of the actuator, the actuator configured to operate the expansion valve of the refrigeration system;
- and
- storing the particular position of the actuator such that the particular position is retrievable by a controller after a power failure.
Dependencies are inferred from the claim text.