Controlling an ultrasonic transmitter
This disclosure relates to detecting fluid in medical tubing. In certain aspects, a method is performed by a data processing apparatus. The method includes controlling repetitive activation of the ultrasonic transmitter. The method also includes receiving a signal from the ultrasonic receiver during an activation of the ultrasonic transmitter. The method also includes determining that fluid is absent or present in a portion of the medical fluid tube based on a comparison between the signal and a threshold value.
1. A medical system comprising:
a medical machine;
a control unit;
a medical fluid tube connected to the medical machine;
an ultrasonic transmitter positioned adjacent to the medical fluid tube;
an ultrasonic receiver positioned adjacent to the medical fluid tube configured to receive one or more signals in response to the activation of the ultrasonic transmitter; and
a computer storage medium encoded with computer program instructions that when executed by the medical system, cause the medical system to perform operations comprising:
controlling repetitive activation of the ultrasonic transmitter, wherein controlling repetitive activation of the ultrasonic transmitter comprises, for each repetition:
activating the ultrasonic transmitter for a first period of 2 to 15 milliseconds; and
deactivating the ultrasonic transmitter for a second period of 998 to 985 milliseconds.
2. The system of claim 1 , wherein controlling repetitive activation of the ultrasonic transmitter comprises activating and deactivating the ultrasonic transmitter in a manner that minimizes cavitation in fluid carried in the medical fluid tube.
3. The system of claim 1 , wherein the first period is 5 milliseconds and the second period is 995 milliseconds.
4. The system of claim 1 , wherein the medical fluid tube has an outer diameter of less than 0.128 inch.
5. The system of claim 1 , wherein the medical fluid tube has an inner diameter of less than 0.031 inch.
6. A method of applying an ultrasonic wave to a tube that contains fluid, the method comprising:
repeatedly activating an ultrasonic transmitter that is positioned adjacent to the tube containing fluid, wherein repeatedly activating the ultrasonic transmitter comprises, for each repetition:
activating the ultrasonic transmitter for a first period of 2 to 15 milliseconds; and
deactivating the ultrasonic transmitter for a second period of 998 to 985 milliseconds.
7. The method of claim 6 , wherein repeatedly activating the ultrasonic transmitter comprises activating and deactivating the ultrasonic transmitter in a manner that minimizes cavitation in fluid carried in the tube.
8. The method of claim 6 , wherein the first period is 5 milliseconds and the second period is 995 milliseconds.
9. The method of claim 6 , wherein the medical fluid tube has an outer diameter of less than 0.128 inch.
10. The method of claim 6 , wherein the medical fluid tube has an inner diameter of less than 0.031 inch.
11. A system comprising:
a fluid tube;
an ultrasonic transmitter positioned adjacent to the fluid tube;
an ultrasonic receiver positioned adjacent to the fluid tube configured to receive one or more signals in response to the activation of the ultrasonic transmitter; and
a computer storage medium encoded with computer program instructions that when executed by the system, cause the system to perform operations comprising:
controlling repetitive activation of the ultrasonic transmitter, wherein controlling repetitive activation of the ultrasonic transmitter comprises, for each repetition:
activating the ultrasonic transmitter for a first period of 2 to 15 milliseconds; and
deactivating the ultrasonic transmitter for a second period of 998 to 985 milliseconds.
12. The system of claim 11 , wherein controlling repetitive activation of the ultrasonic transmitter comprises activating and deactivating the ultrasonic transmitter in a manner that minimizes cavitation in fluid carried in the medical fluid tube.
13. The system of claim 11 , wherein the first period is 5 milliseconds and the second period is 995 milliseconds.
14. The system of claim 11 , wherein the fluid tube has an outer diameter of less than 0.128 inch.
15. The system of claim 11 , wherein the fluid tube has an inner diameter of less than 0.031 inch.