New tools to monitor compressed air
Compressed air is an expensive energy source. In fact, it is nearly 10 times more expensive than electricity. And studies show that up to 50% of generated compressed air is lost due to leakage, improper use, and lack of maintenance. This is according to experts at Van Putten Instruments B.V., headquartered in Delft, The Netherlands.
Engineers at the company are addressing these problems with a suite of products and software for managing the production and use of compressed air. In many cases, they say, demand for compressed air can be reduced by optimizing a system with proper air management, pressure control, and piping configurations, as well as eliminating leaks. The result can be substantial energy and cost savings.
The company’s product range includes flowmeters and other sensors for measuring compressed-air-system performance, and monitoring systems for total compressed-air management. Some can interface with third-party energy-efficiency software and plant-management packages.
Flowmeters are used to establish baseline airflows and energy use. They allow technicians to perform air audits and system checks and, when permanently installed, continually monitor a system so users can proactively control leaks, scrutinize power consumption and pressure losses, and plan for maintenance to prevent downtime.
The company’s mass flowmeters, based on proprietary, in-house technology, are described as integrated circuits that combine a Wheatstone bridge with a heater. For example, VPFlowScope sensors simultaneously measure mass flow, temperature, and pressure; have a 500,000-point data logger; and include a built-in display with keypad for configuration.
They combine an extremely wide measurement range with flow-direction sensitivity. This lets users measure flow in loop networks and systems with air receivers, which can often be difficult to assess.
The product family consists of wet and dry airflow meters. This lets it monitor wet supply-side pretreated air, as well as clean, dry demand-side air, in piping systems from 0.5 to 20 in. in diameter. Both types use the same display module, so users can measure virtually any compressed-air system with a single instrument.
An in-line version of the VPFlowScope, for 0.5, 1.0, and 2.0‑in.-diameter pipes, also provides real-time flow, pressure, and temperature readings with bidirectional sensitivity. Several versions cover flows from 0.13 to 600 scfm, with a 0.5% accuracy. Pressure range is 0 to 250 psi with ±1.5% accuracy; and temperature rating is 32 to 140°F with ±1° accuracy.
In addition to these products, other flowmeters are available for point-of-use consumption and leak detection; as well as current sensors that measure power input to the compressor’s electric motor. When combined with a flowmeter, current measurements can be used to determine actual compressor efficiency.
To record data and monitor a system, the VPFlowTerminal is a plug-and-play, wall-mount display with built-in power supply and 2 million-point data logger. The unit has five sensor inputs — one input for a mass flowmeter and four generic analog inputs — and it can record up to eight channels. Because it can track main flow and compressor power consumption, it’s suited for monitoring compressor efficiency. It can also be used for air audits because all information is recorded within one data logger.
Another monitoring tool, VPStudio software, lets users configure other VP Instruments products, view real-time measurements, retrieve data, schedule data-log sessions, set logging intervals, and adjust flow-meter parameters. VPStudio communicates with other devices via a PC’s USB port.
To manage a complete network, VPVision software monitors, stores, and analyzes flow and other data and can estimate potential savings. It lets users:
- Get real-time feedback on actual compressed-air consumption.
- Simultaneously monitor multiple compressors.
- Track and manage leakage.
- Allocate compressed-air costs to individual departments or production lines.
- View cost evaluation and savings reports.
- Benchmark different plants around the world on efficiency and costs.
- Generate the necessary documentation for utility incentives.
VPVision can be expanded to receive and consolidate data such as compressor electricity demand and flow-media dew point. It can also be integrated into a plant’s existing SCADA system. VPVision can also be connected to the Internet, allowing remote access by designated staff using devices such as an iPad, smartphone, tablet, or Web browser.
Because no two compressed-air systems are the same, VPVision systems are customized to the user’s requirements. Application engineers at VP Instruments can calculate the required investment and estimate ROI up front, before a potential user makes a purchasing decision. The company’s compressed-air management tools are currently being used in food-processing plants, bakeries, steel mills, and foundries, among others.