For safety equipment reliable performance is paramount. These products are typically used in hazardous environments where any type of failure could be dangerous for the user. In this instance, we’re specifically looking at respirator purifying systems, such as the North Compact Air 200 Series Powered Air Purifying Respirator (PAPR).
This respiratory protection system filters out harmful particles from the air to enable workers to safely move in dangerous areas. It consists of a body-worn filter system which connects to a facepiece or hood. To ensure the worker has maximum flexibility the system is worn on the lower back like a belt.
Previously the operator would need to estimate when the system was low on battery, or frequently check the filters were clear. With LEDs and speakers installed simple visual and audible alerts could remove some of the guesswork. Now with vibration alerting added, there are three different warning signs.
There are three alert conditions; 10% battery remaining, 5% battery remaining and blocked or clogged filters. All three ‘alarms’ work together to warn the operator of each situation. The table below shows the conditions:
|Alarm Conditions||Audible Alarm||Vibratory Alarm||Visual Alarm|
|10% battery life remaining||4 Beeps||Vibration for 4 seconds at 30-second intervals||Check battery LED changes from green to red|
|5% battery life remaining||Continuous beep until the battery expires||(OFF to save battery)||Check battery LED remains red|
|Blocked or clogged filters||Continuous beep||Vibration for 3 seconds at 10-second intervals||Check filter LED changes from green to red|
This is a great example of how vibration alerting can enhance the effectiveness of existing audible and visual notifications to increase safety performance, thereby adding value to the customer. It also makes the product more suitable for use in loud or noisy situations, or even when the operator has protective earphones.
There is one vibration pattern, coupled with beeping and LED pattern, to signify the battery is at a low level. When the battery reduces further, to 5%, the vibration motor is switched off to save power and the visual and audible aspects change to suggest immediate action is required.
Also to highlight the filters are not fully operational, and therefore the user is potentially in danger, a different vibration pattern is used. This has shorter vibration bursts, but at a much higher frequency to create a sense of urgency. This is complemented with a continuous beep and red ‘check filter’ LED.
In vibration alerting applications such as this, the vibration amplitude and frequency are usually the most important characteristics. This is largely due to the protective clothing, where vibrations will be dampened. As low frequencies attenuate less in soft materials, a slower motor with a high vibration amplitude is required. With limited space in a body-worn design, the best choice is the 312-107 that the North Compact Air 200 Series PAPR uses.
At 6,800 RPM it is one of our slowest vibration motors (leading to low vibration frequency) but the large eccentric mass makes it the strongest sub 45 mm vibration motor. It also benefits from a 3 V rated voltage, making it easy to power from battery packs. See the link below to view the product page and find pricing.