Design and Construction of a Device to Evaluate the Performance of Variable Orifice Flow Meters (VOFM)

Round 1

Reviewer 1 Report

The manuscript entiled Design and Construction of a Device to Evaluate the Performance of Variable Orifice Flow Meters is experimnetal study of measurements of flow rate passing through an orifice. The author should revise the weakness in the manuscript. I commented as follows;

1.Validity of the experimental method should be shown.

2.I felt that pressure drops could not be measured below 100 Pa. The author should show validity of measurements.

3.The author should use m^3/s (SI unit) of flow rate. Moreover, In Fig. 10, the experimental results should be shown in a log-log plot.

4.Reynolds number was not shown. The author should estimate them.

5.The author should separate the discussions and conclusions.

6.Many symbolds and letters are used. The author should summarize them as a nomenclature.

I felt that English id poor.

Author Response

1.Validity of the experimental method should be shown.

The review is welcomed and the experiment description is enhanced.

2.I felt that pressure drops could not be measured below 100 Pa. The author should show validity of measurements.}

While measurement was possible, the pressure drop for low flows is not linear in the VOFM. The review is included in the article.

3.The author should use m^3/s (SI unit) of flow rate. Moreover, In Fig. 10, the experimental results should be shown in a log-log plot.

In scientific and medical literature, it is common to use units for pressure drop in terms of pascals or centimeters of water column. Similarly, for mechanical ventilation systems in medical applications, the unit of liters per minute is often employed. This consideration is important since these are the types of professionals to whom this publication could be directed, including engineers and relevant practitioners.

Additionally, the use of logarithmic scales would alter the desired linear behavior that is intended to be evaluated and enhanced in the final measurement device. Lastly, even though the unit L/min is outside the SI system, it is widely accepted for use within the SI context.

4.Reynolds number was not shown. The author should estimate them.

We calculated the Reynolds number for the circular pipe upstream of the VOFM us-ing the equations for a circular section, to verify any potential turbulence influence that could affect the VOFM beam. According to the Reynolds number, we found that for a flow rate of around 35 L/min, the transition from laminar to turbulent flow begins, and for a flow rate of 67 L/min, the flow regime will be turbulent. For this reason, we can assert that the increased variance in pressure drop is due to the flow regime. However, we did not calculate the Reynolds number directly at the VOFM section. Therefore, we consider it important to design mathematical models and conduct experiments to assess the flow regime precisely at the VOFM, considering the variable geometry. This would enable the optimization of the VOFM beam geometries for potential plate vibrations and, thus, enhance its accuracy as a flow measurement sensor.

 

The review is welcomed and the experiment description is enhanced.

 

5.The author should separate the discussions and conclusions.

The review is welcomed and the experiment description is enhanced.

6.Many symbolds and letters are used. The author should summarize them as a nomenclature.

The review is welcomed and the experiment description is enhanced.

 

 

 

Reviewer 2 Report

See the attachment. 

Comments for author File: Comments.pdf

Author Response

1. The paper is very interesting and deals with a subject of real interest which arose with the COVID-19 pandemic when the need of ventilators led to the development of multiple “custom-made” solutions to compensate for
the lack of medical devices. While the paper itself presents a very interesting device to monitor multiple parameters of the fluid flow in a pipe it is a bit difficult for me to understand the real usage in a medical scenario, and I do believe that this should be explained better.

R/The equipment was designated proximal to the patient. The wording has been improved by incorporating the reviewer's suggestions.

2. Thus…what ventilators are you targeting? In case you are targeting a medical device, you don’t really have access to its internal components not to its regulation solutions, because as a medical device you cannot interfere with the device and then still use it on patients (the device itself has all the measurement and safety protocols to ensure that the proper flow intake, pressure, volume and O2 concentration is provided to the patient). Also, depending on the nature of lung affliction (as in COVID) there are also some other parameters of interest, but this is outside the scope of the paper. In case you are targeting custom solutions they should be at least marginally discussed, targeting their way of functioning and the limitations they have due to the nature of construction. For example: the most accurate way to regulate the pressure intake is to use a fluid (water) as a pressure limiter (see the Milano ventilator). Of course, the limitation here is that the fluid will become a potential source of microbial cultures and so on, and it involves the use of some volume of fluid thus making it large.

R/ The equipment is used to evaluate VOFMs. The reviewer's revisions have been embraced, and the description has been enhanced to address flow measurement proximal to the patient, regardless of the ventilator or condition.

3. A second aspect is the O2 and air mixture device which is the most “difficult” to achieve when using limited resources as at the start of the pandemic (one simple example throughout Europe was the lack of any proportional valves).

R/ The tests were conducted with normal air (21% O2), and the O2 sensor was not enabled for the tests. Graph 8 has been corrected.

4. Line 180….as you used the metric measurement throughout the paper I’d put the PSI in brackets and the kPa
value in front.

R/ The reviewer's revisions have been embraced

As a small remark on the text, please use VOM (as abbreviation) throughout the paper, as in some cases you changed it in MOV.

R/ The reviewer's revisions have been embraced. The other revisor suggest VOFM. The text, equations, and graphs were updated to replace MOV and VOM with VOFM.

As a small remark in figure 8, how did you achieve a 9.5% O2 concentration with your device as the normal O2 levels in air (without any O2 intake) is 21%?

R/ The text, equations, and graphs were updated to replace MOV and VOM with VOFM. Incluided Fig 8, this is error.  thanks

Reviewer 3 Report

The authors present a novel and highly original work. However, some issues need to be resolved before it can be recommended for publication.

The authors are advised to use the abbreviation VOFM instead of VOM.

The introductory section is very complete, but it would lack an initial part where the research carried out is contextualised and similar research is presented. The authors have only worked with Espacenet, and more scientific references are necessary to publish a document other than a patent in a scientific journal.

All elements included in the equations of the theoretical part should be described and the units of measurement should be indicated.

The electronic components should be explained in more depth.

The resolution of Figure 9 is very poor.

Table 6 is very blurred and should be corrected.

The discussion and conclusions should be separated. In addition, the conclusions should be expanded to include the limitations of this research.

Some sections of the original Template have disappeared. The bibilography is not in format.

Author Response

1. The authors present a novel and highly original work. However, some issues need to be resolved before it can be recommended for publication. R/We hope that the contribution of your revisions improves the clarity of our research for the benefit of the scientific community.

2. The authors are advised to use the abbreviation VOFM instead of VOM.

The review is welcomed and the experiment description is enhanced.

3. The introductory section is very complete, but it would lack an initial part where the research carried out is contextualised and similar research is presented. The authors have only worked with Espacenet, and more scientific references are necessary to publish a document other than a patent in a scientific journal.

There are no existing investigations for the dimensions of the VOFM in the conducted review; relevant information is solely from patents. This is the reason we embarked on the research

 

4. All elements included in the equations of the theoretical part should be described and the units of measurement should be indicated.

The review is welcomed and the experiment description is enhanced.

5. The electronic components should be explained in more depth.

The review is welcomed and the experiment description is enhanced.

6. The resolution of Figure 9 is very poor.

The review is welcomed and the experiment description is enhanced.

The review is welcomed and the experiment description is enhanced.

7. Table 6 is very blurred and should be corrected.

The review is welcomed and the experiment description is enhanced.

8. The discussion and conclusions should be separated. In addition, the conclusions should be expanded to include the limitations of this research.

The review is welcomed and the experiment description is enhanced.

9. Some sections of the original Template have disappeared. The bibilography is not in format.

The review is welcomed and the experiment description is enhanced. Thanks.

Round 2

Reviewer 1 Report

Revisions are satisfied.

Minor editing of English language required.

Reviewer 2 Report

Based on the answers and the corrections in the paper everything is much more clear and I recommend the publication of the paper. No additional comments.