Southampton University spin-out produces novel parasitic energy harvester to power wireless devices

Perpetuum: a CIPA case study

When Steve Roberts joined Southampton University spin-out Perpetuum as technical manager in 2005, his challenge was to turn a ‘proof-of-concept’ demonstrator into a patentable and marketable product that would act as a reliable, safe and maintenance-free power source for wireless sensor nodes, for at least 20 years.

The resulting Perpetuum vibration energy harvesting device - the PMG17 - is a safe and long-lasting alternative to batteries and hard-wiring. It already has the petrochemical industry ATEX classification and is being used in several installations, including Shell’s Nyhamna gas plant in Norway where it powers wireless vibration and temperature sensors – many in hazardous areas.

According to Shell, the pilot wireless vibration and temperature monitoring system in Norway has been a success and opens the way for the use of wireless in-plant technology as standard practice around the world. Shell alone has around 20 million sensor points worldwide, all of which are sheduled to go wireless over the next ten years. Perpetuum expects to have a dominant position in that market and already has the capacity to produce 5,000 units a month at its manufacturing base in nearby Portsmouth, which it plans to ramp up as the technology gains market acceptance.
Perpetuum’s microgenerator uses a highly-engineered resonant magnet and coil arrangement to convert mechanical vibration into electrical energy that can be used to power complete wireless sensor systems, eliminating the need for batteries and hard wiring. The energy produced is sufficient to power several low-energy wireless sensors over a variety of wireless networks.

Keeping ahead of the competition

Steve Roberts has worked with patent attorney Peter Jenkins, of Page White & Farrer, to file another ten families of patents, building on the two original patents granted to the university. This gives the company a very strong position in the huge international market for this kind of power source.

“Although the basic principles of vibration energy harvesting have been known for years,” Steve Roberts explains, “it’s the move to wireless sensors in the petrochemical industry that has really given us the impetus to develop a marketable product. The cost of downtime – for example, on an offshore oil production platform – is colossal, so the operators use sensors very widely to ensure they detect wear and potential problems early, well before they cause a breakdown. In the oil industry, it typically costs about $30,000 to install a hard-wired sensor, so you can appreciate why there is a big move to wireless sensors.”

Plant managers use accelerometers and thermometers to monitor bearings and rotors in equipment such as motors, fans, pumps and compressors. Temperature rises or unusual vibrations can indicate defects or or misaligned shafts which can eventually lead to machine failure.

By monitoring changes in a machine’s temperature and vibration, an engineer can interpret its condition and predict equipment failure. Preventative measures, such as a planned maintenance and repair programme, can then be taken, avoiding costly down-time.

Until recently, most monitoring has involved costly hard-wired sensors or infrequent checks by maintenance personnel using hand held monitoring equipment. Perpetuum’s vibration energy harvesting devices enable continuous monitoring of critical plant and machinery over a long period, leading to improved economy.

Fast-track patent protection

According to Peter Jenkins, Perpetuum’s patent attorney since the business was set up in 2004, the UK is good place to start if you want international patent protection. “The UK Intellectual Property Office (IPO) has done a great job in establishing a quick, low-cost system, yet with substantive examination of the patentability of the invention,” he explains. “With Perpetuum’s patents, we start by filing in the UK. We normally request combined search and examination, which means we can receive an opinion on patentability in as little as four to six months. By asking for accelerated publication, this can lead to a granted UK patent very quickly, even within 15 months. In parallel, we use the International and European patent systems to obtain patents outside the UK.”

Perpetuum’s portfolio of granted patents has been invaluable in attracting investment into the business. The patent for the proof-of-concept demonstrator helped secure seedcorn funding of £300,000 at the time the company was spun out from Southampton University’s Department of Electronics and Computer Science in 2004. Since the, two further rounds of fundraising have secured £2.2m and £5m of investment. “Our intellectual property (IP) rights were essential in winning investors’ confidence,” says Steve Roberts. “One of the venture capital companies involved even brought in a specialist lawyer to carry out a review of our IP.”

New product demonstrates advantages

The latest addition to Perpetuum’s product range is the wSNAK – the Wireless Sensor Node Assessment Kit. The kit consists of four energy harvester-powered wireless sensor nodes which send vibration and temperature data to a laptop-based receiver. Each sensor node runs an accelerometer with integrated temperature sensor. Data is transmitted from each node to a receiver which can be up to 100 metres away. Vibration and temperature data can be displayed on a laptop and basic level alarms may be set.

Steve Roberts explains that the kits have been developed to allow potential users to test the reliability of Perpetuum’s vibration energy harvesting devices as part of a working sensor assembly. “These products will enable OEMs and end users to accelerate the wireless revolution,” he says. “They make it possible for plant managers to achieve a rapid improvement in operational performance by increasing reliability and lowering costs.”

For further information, see:

Peter Jenkins, Page White & Farrer
Tel: 020 7831 7929