Piping length measuring system and piping length calculating apparatus

Patent metadata

Field	Value
Publication number	US-9644937-B2
Application number	US-201113980948-A
Country	US
Kind code	B2
Filing date	Jan 24, 2011
Priority date	Jan 24, 2011
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A frequency characteristics measurer is disposed in the vicinity of an end of refrigerant piping, the end of which is connected to an outdoor unit, that connects the outdoor unit and an indoor unit of an air conditioner, and measures frequency characteristics of the refrigerant piping. A filter is attached at a position between the outdoor unit and a position where a terminal of the frequency characteristics measurer is connected, so as to wrap the refrigerant piping. A piping length calculator is connected to the frequency characteristics measurer via an interface cable, and acquires, via the interface cable, frequency characteristics measured by means of the frequency characteristics measurer. The piping length calculator extracts a lowest anti-resonant frequency from the acquired frequency characteristics, and calculates the length of the refrigerant piping on the basis of the extracted lowest anti-resonant frequency.

First claim

The invention claimed is:

1. A piping length measuring system, comprising:
a frequency characteristics measuring apparatus;
a piping length calculating apparatus communicatively connected to the frequency characteristics measuring apparatus via a predetermined communication interface; and
a filter, wherein
the frequency characteristics measuring apparatus outputs a test signal at different frequencies from one end portion of refrigerant piping connecting an outdoor unit and an indoor unit of an air conditioner, measures frequency characteristics of the refrigerant piping by measuring at the end portion reflected signal levels at the different frequencies, and transmits the frequency characteristics measured to the piping length calculating apparatus,
the filter, attached between a measuring site on the refrigerant piping measured by the frequency characteristics measuring apparatus and the outdoor unit or the indoor unit nearest to the measuring site, prevents a test signal from flowing into the outdoor unit or the indoor unit during the measuring, and
the piping length calculating apparatus comprises a controller that extracts a lowest anti-resonant frequency from the frequency characteristics measured by the frequency characteristics measuring apparatus, and calculates a length of the refrigerant piping on the basis of the extracted lowest anti-resonant frequency.

2. The piping length measuring system according to claim 1 , wherein
the piping length calculating apparatus extracts a plurality of anti-resonant frequencies under a given condition from the frequency characteristics measured by the frequency characteristics measuring apparatus, determines whether or not a branching exists in the refrigerant piping on the basis of the extracted plurality of anti-resonant frequencies, and in the case of determining that the branching does not exist, calculates a length of the refrigerant piping on the basis of the lowest anti-resonant frequency, whereas, in the case of determining that the branching does exist, selects anti-resonant frequencies that are not the lowest anti-resonant frequency and do not correspond to harmonic components from among the extracted plurality of anti-resonant frequencies, and calculates a length of the refrigerant piping on the basis of the selected anti-resonant frequencies.

3. The piping length measuring system according to claim 2 , wherein
the piping length calculating apparatus determines that branching does not exist in the refrigerant piping in the case where the extracted anti-resonant frequencies other than the lowest anti-resonant frequency correspond to harmonic components of the lowest anti-resonant frequency.

4. The piping length measuring system according to claim 2 , wherein
in the case of determining that branching does exist in the refrigerant piping, the piping length calculating apparatus calculates lengths respectively corresponding to anti-resonant frequencies that are not the lowest anti-resonant frequency and do not correspond to harmonic components to total the respective lengths, thereby calculating the length of the refrigerant piping.

5. The piping length measuring system according to claim 1 , wherein
the measuring site on the refrigerant piping measured by the frequency characteristics measuring apparatus at the end portion of the refrigerant piping, the end of which is connected to the outdoor unit.

6. The piping length measuring system according to claim 1 , wherein
the filter comprises a ferrite core.

7. The piping length measuring system according to claim 1 , wherein
the frequency characteristics indicate the ratio of a signal level of the test signal output to the refrigerant piping by the frequency characteristics measuring apparatus to a signal level measured by the frequency characteristics measuring apparatus.

8. The piping length measuring system according to claim 1 , wherein
the frequency characteristics indicate peak values of the voltage on the refrigerant piping measured by the frequency characteristics measuring apparatus.

9. The piping length measuring system according to claim 1 , wherein
the frequency characteristics indicate effective values of the voltage on the refrigerant piping measured by the frequency characteristics measuring apparatus.

10. The piping length measuring system according to claim 1 , wherein
the piping length calculating apparatus further comprises a display to display the calculated length of the refrigerant piping.

11. A piping length calculating apparatus comprising:
an interface that communicates with a frequency characteristics measuring apparatus that outputs a test signal at different frequencies from one end portion of refrigerant piping connecting an outdoor unit and an indoor unit of an air conditioner and measures frequency characteristics of the refrigerant piping by measuring at the end portion reflected signal levels at the different frequencies;
a controller that extracts a plurality of anti-resonant frequencies under a given condition from the frequency characteristics measured by the frequency characteristics measuring apparatus, determines whether or not a branching exists in the refrigerant piping on the basis of the extracted plurality of anti-resonant frequencies, and in the case of determining that the branching does not exist, calculates a length of the refrigerant piping on the basis of a lowest anti-resonant frequency from among the extracted plurality of anti-resonant frequencies, whereas, in the case of determining that the branching does exist, selects anti-resonant frequencies that are not the lowest anti-resonant frequency and do not correspond to harmonic components from among the extracted plurality of anti-resonant frequencies, and calculates a length of the refrigerant piping on the basis of the selected anti-resonant frequencies; and
a display that displays the calculated length of the refrigerant piping.

12. A non-transitory computer readable recording medium having stored thereon a program causing a computer including a controller and an interface that communicates with a frequency characteristics measuring apparatus that outputs a test signal at different frequencies from one end portion of refrigerant piping connecting an outdoor unit and an indoor unit of an air conditioner and measures frequency characteristics of the refrigerant piping by measuring at the end portion reflected signal levels at the different frequencies to realize the functions of:
extracting a plurality of anti-resonant frequencies under a given condition from the frequency characteristics measured by the frequency characteristics measuring apparatus, determining whether or not a branching exists in the refrigerant piping on the basis of the extracted plurality of anti-resonant frequencies, and in the case of determining that the branching does not exist, calculating a length of the refrigerant piping on the basis of a lowest anti-resonant frequency from among the extracted plurality of anti-resonant frequencies, whereas, in the case of determining that the branching does exist, selecting anti-resonant frequencies that are not the minimum anti-resonant frequency and do not correspond to harmonic components from among the extracted plurality of anti-resonant frequencies, and calculating a length of the refrigerant piping on the basis of the selected anti-resonant frequencies; and displaying the calculated length of the refrigerant piping on a display.

13. A method for calculating a length of a piping, the method comprising:
outputting, by a frequency characteristics measuring apparatus, a test signal at different frequencies from one end por

Assignees

• Mukai Takuya
• Higuma Toshiyasu
• Mitsubishi Electric Corp

Inventors

• Mukai Takuya
• Higuma Toshiyasu

Classifications

• G01B7/02 Primary

  for measuring length, width or thickness (G01B7/004, G01B7/12 take precedence) · CPC title

• F24F1/26

  Refrigerant piping · CPC title

• G01B7/042

  for measuring length · CPC title