Review Reports - Monitoring of the Operating Membrane Condition Using PZT Based EMI of External Steel Pipe

Round 1

Reviewer 1 Report

Minor inaccuracies that must be corrected:

line 74: What is the meaning of NDT?

line 102: mm3 and mm2 must be mm³ and mm²

In figure 11: must be identified the xx and yy axes with the respectives units. It is also important the indication of the R² value in the graphic

Author Response

Review 1: line 74: What is the meaning of NDT?

Reply 1: It means Non-destructive Tests. The full name was added in manuscript.

Review 2: line 102: mm3 and mm2 must be mm³ and mm²

Reply 2: Revised.

Review 3: In figure 11: must be identified the xx and yy axes with the respectives units. It is also important the indication of the R² value in the graphic

Reply 3: Revised.

Reviewer 2 Report

Authors have presented a method for the evaluation of membrane condition in terms of possible defects. They proposed the measurements of PZT-based electro-mechanical impedance (EMI) in an an external steel pipe in order to improve the sensitivity and speed of commonly used pressure decay test PDT. The manuscript could be published, however several issues need additional clarification.

Merit remarks:

A scheme of experimental setup is necessary.
Parameter values for Eq.1 should be given.
In this method a possible defect of the membrane is revealed by a pressure drop during PDT. In my opinion, a direct measurement of gas pressure in a steel pipe is still a better indication of a pressure drop than its indirect measurement based on EMI. The statement (line 203): “… can be a solution to improve the sensitivity and speed of PDT” should be more justified in the discussion of the results.
How versatile is the proposed method and especially Eq. 2?
The title is somewhat misleading. It suggests:
- the ongoing monitoring of the operating membrane condition
- that the manuscript deals with a “PTZ-based membrane” instead of PZT-based EMI tests

Manuscript editing:

Check and suplement, if necessary, axis titles and units of measure throughout the text. The quality of figures should be improved before publication.
Provide explanations to every symbol in Eq. 1.

Author Response

Review 1: A scheme of experimental setup is necessary.

Reply 1: A scheme of experimental setup is added.

Review 2: Parameter values for Eq.1 should be given.

Reply 2: All parameters that used in Eq.1 was added in manuscript.

Review 3: In this method a possible defect of the membrane is revealed by a pressure drop during PDT. In my opinion, a direct measurement of gas pressure in a steel pipe is still a better indication of a pressure drop than its indirect measurement based on EMI. The statement (line 203): “… can be a solution to improve the sensitivity and speed of PDT” should be more justified in the discussion of the results.

Reply 3: As reviewer’s comment, the proposed method used to the pressure gauge which directly measure the gas pressure as reference data to derive Eq.2 that can estimate the pressure by measuring the EMI of steel pipe which attached in PDT equipment. The PDT can be done easily with proposed PDT equipment which attached the EMI measurement pipe, also the PDT can be performed even if the pressure gauge was not installed. Furthermore, the proposed method can find the pressure drop before maximum pressure of PDT due to the high sensitivity of EMI, while the conventional PDT can detect the defect of membrane after some minute after gas-liquid substitution.

Review 4: How versatile is the proposed method and especially Eq. 2?

Reply 4: The pressure in the measurement pipe can be estimated by measuring impedance using Eq.2. This equation can use all of the membrane which performed PZT with proposed PDT equipment with PZT attached steel pipe. Thus the Eq.2 can be generally used to estimate pressure of internal pipe using proposed system.

Review 5: The title is somewhat misleading. It suggests:

the ongoing monitoring of the operating membrane condition
that the manuscript deals with a “PTZ-based membrane” instead of PZT-based EMI tests

Reply 5: The title is changed as “The Monitoring of the Operating Membrane Condition using PZT based EMI of External Steel Pipe” as the reviewer’s comment. The research used the PZT(Lead Zirconate Titanate) to measure the EMI(Electro-mechanical Impedance). So the method name was remains as “Electro-mechanical Impedance of External Steel Pipe”. Also the final goal of this study is to monitor the condition of membrane without water stop(Ongoing) but at this step it does not achieve ongoing monitoring. It should need substrate the water to air and this cannot be done with ongoing. So the word ‘ongoing’ cannot be used at this stage.

Review 6: Check and supplement, if necessary, axis titles and units of measure throughout the text. The quality of figures should be improved before publication.