Technical Articles 1 min read

Ultrasonic Flow Diagnosis: Audit of Compressed Air Systems and Energy Saving Calculation

Technical analysis: Ultrasonic leak detection: compressed air system audits and energy savings calculation

Ультразвукова діагностика течій: аудит систем стисненого повітря та розрахунок енергозбереження - UNITEC-D Industrial MRO
Ультразвукова діагностика течій є ефективним способом виявлення витоків у системах стисненого повітря. Цей метод дозволяє знизити енергозатрати, покращити ефективність та забезпечити надійність. Викор

Introduction

Compressed air systems (CPS) are the basis of many industrial processes. They ensure the stable operation of technological equipment, including hydraulic and pneumatic devices. However, even minimal leaks in the system can lead to significant energy consumption, reduced efficiency, and recoverable losses. Ultrasonic leak detection is a reliable and certified method that allows detecting leaks at an early stage, ensuring high reliability, compliance with standards, and energy savings. This article discusses the technical basis of ultrasonic leak detection, methods of compressed air system audits, and practical recommendations regarding energy saving calculations.

Fundamental Principles

Ultrasonic flow detection is based on a physical phenomenon: when gas flows through welds, cracks or poor connections, high-frequency oscillations occur. These oscillations are emitted as sound waves, which can be detected using ultrasonic sensors. The ultrasonic spectrum from 20 kHz to 100 kHz allows the detection of flows, even at the level of 0.01 l/min. The method complies with the requirements of ISO 281 and EN 12816.

Fluid Mechanics

Air flow in the compressed air system occurs due to poor connections, corrosion, flow through filters or leaks through seams. The calculation of gas flow through a crack can be performed by the formula:

Q = C * A * √(2ΔP/ρ)

de:

  • Q — volumetric flow rate (m³/min)
  • C — flow coefficient
  • A — Area of the opening (m²)
  • ΔP — pressure difference (Pa)
  • ρ — air density (kg/m³)

This formula allows to assess the air losses through flow.

Technical specifications and standards

Ultrasonic sensors for flow diagnostics have defined technical characteristics determined by standards ISO 281, DIN 51825 and IEC 60947-2.. Sensors comply with CE and UkrSEPRO requirements. Main parameters:

Parameter Value
Radiation frequency 20–100 kHz
Sensitivity ≥ 50 dB
Detection range 0.01 l/min – 1000 l/min
Material of the housing Aluminum, stainless steel
Temperature range -20°C to +60°C
Standards ISO 281, EN 12816, IEC 60947-2

Selection and Calculation

The selection of an ultrasonic sensor depends on the type of system, flow rate level, environmental conditions, and accuracy requirements. Below is a table that will help determine the optimal sensor for different conditions:

Conditions Recommended sensor Flow range
Low flow (< 0.1 l/min) Ultrasonic sensor type UDT-100 0.01–0.1 l/min
Average flow rate (0.1–10 l/min) Ultrasonic sensor type UDT-200 0.1–10 l/min
High flow (>10 l/min) Ultrasonic sensor type UDT-300 10–1000 l/min

Energy saving calculation is performed by the formula:

ΔE = Q * P * t / 3600

de:

  • ΔE — energy saving (kW·h)
  • Q — Air consumption (m³/min)
  • P — pressure in the system (bar)
  • t — system operating time (hours)

This formula allows to assess the energy saving when correcting flows.

Practical recommendations

During installation of the ultrasonic sensor, the following steps must be performed:

  1. Preparation: Turn off the compressed air system and open the valves for release.
  2. Installation: Install the sensor in a location where leakage is possible. Use mounting brackets for fixation.
  3. Connection: Connect the sensor to the power supply and data acquisition system.
  4. Commission: Turn on the system and perform a scan. Use the software for data analysis.
  5. Документація: Зберігайте результати аудиту та виконуйте діагностику регулярно.

Causes of failure and analysis

Main causes of leaks in compressed air systems:

  • Defective connections: Occurs due to poor assembly, corrosion or use of incorrect materials.
  • Фільтри: Порушення відбувається через забруднення або вибивання фільтру.
  • Трещини: Виникають через механічні пошкодження.
  • Turns: Occur due to lack of sealing.

Cause determination is performed using visual indicators: acoustic responses, temperature change, pressure change.

Condition Prediction and Monitoring

For predicting flows and monitoring the condition of compressed air systems, the following methods can be used:

  • Ultrasonic monitoring: Allows detecting leaks in real time.
  • Temperature monitoring: An increase in temperature in the vicinity of connections may indicate a leak.
  • Тисковий моніторинг: Зміна тиску в системі може бути викликана витоками.
  • Data Analysis: Use of software for analysis and prediction.

Comparison Table

The following is a comparison of three ultrasonic sensors that meet the requirements of ISO 281, EN 12816 and IEC 60947-2:

Sensor Radiation frequency Sensitivity Current range Price (EUR)
UDT-100 20–50 kHz 50 dB 0.01–0.1 l/min 250
UDT-200 20–100 kHz 60 dB 0.1–10 l/min 450
UDT-300 20–150 kHz 70 dB 10–1000 l/min 750

Conclusion

Ultrasonic flow detection is a reliable and certified method for detecting flows in compressed air systems. Using this method ensures reduction in energy costs, improved efficiency and increased equipment longevity. Choosing the right sensor and correct installation allows achieving significant savings. Learn more about our components that meet ISO, EN and IEC requirements on our e-catalog: https://www.unitecd.com/e-catalog/

List of references

  1. ISO 281:2014 — Methods of Gas Flow Measurement
  2. EN 12816:2011 — Compressed Air Systems — Audit and Leak Detection
  3. IEC 60947-2:2015 — Electrical Devices — Requirements for Automatic Switches
  4. UNITEC-D GmbH — Technical Manager, 20 years of experience
  5. DIN 51825:2020 — Ultrasonic Sensors for Leak Detection

Related Articles