The precise control of temperature and humidity is an important operating consideration in many chemical, food and beverage, pharmaceutical, biomedical, and other industrial and manufacturing facilities. Reliable monitoring is an essential part of the overall control scheme.
Unwanted temperature excursions can compromise corporate and regulatory requirements, and have consequences of unanticipated system shutdowns and product losses. Such temperature excursions can occur as a result of operator error, power outages, system failures in refrigeration and freezer units, air-conditioning systems, drying chambers, storage rooms, and other malfunctions.
A supplier of implantable orthopedic components, manufactured from both human tissue and synthetic materials, needed reliable temperature monitoring with alarming and communication capabilities when defined high- and low-temperature thresholds were exceeded. These temperature-sensitive products are stored in a central distribution facility and shipped to hospitals all over the United States.
At its 75,000 ft2 storage and distribution facility, the company handles more than $200 million of inventory each year. The products must be maintained within a defined temperature range to protect their integrity, and meet stringent regulatory requirements.
Since 2009, the facility has used the Saveris temperature-monitoring system from Testo Inc., Sparta, N.J., to provide continuous temperature monitoring, data collection, and real-time alarm capabilities.
The Testo Saveris H2E Ethernet Probe (left) and the Saveris PtD wireless probe. Images: Testo Inc.
The system continuously monitors temperatures, produces reports on demand, and sends notifications when there is a deviation from a setpoint. Notification formats include visible and audible alarms for in-plant personnel, or remote communication via email, pop-up messaging, and text messages, with customizable text and format.
The system continuously monitors temperatures, produces reports on demand, and sends notifications when there is a deviation from a setpoint. Notification formats include visible and audible alarms for in-plant personnel, or remote communication via email, pop-up messaging, and text messages, with customizable text and format.
Wireless remote monitoring
The distribution facility stores the temperature-sensitive, implantable orthopedic devices in three self-contained refrigeration units called vertical lift modules (VLMs), each measuring 20 feet long by 28 feet high and six feet wide.
A series of wireless temperature sensors use radio-frequency (RF) communications to transmit temperature data from inside the VLMs to a base unit that provides centralized data collection and alarm management. While a router—which is typically installed between the wireless device and the base unit to improve the radio link or extend the transmission distance—is not needed for its current setup, the company installed one to provide additional flexibility and for future growth.
Using Saveris software on a PC, users can access data and generate reports.
A single base unit can incorporate 150 wireless and Ethernet probes or 450 measurement channels, allowing it to save 40,000 readings per measurement channel, independent of a personal computer. The base unit can be connected to one or more computers using either a USB or Ethernet cable.
Using the Saveris software installed on a personal computer, users can access and display data and generate PDF reports. If the computers are not running, the base unit issues an alarm when threshold values are exceeded as a flashing LED display on the unit, an audible alarm, or via email, text message, or pop-up message on the screen of another computer.
An alarm sounds if communication is lost between any radio-frequency temperature probes and the base unit. An emergency battery, coupled with the internal memory of the temperature probe, ensures that data are not lost during power outages.
The Saveris system can be configured using a variety of temperature probes, with options such as wireless versus hard-wired probes, internal or external sensors, and optional data display right at the probe.
A base unit can save 40,000 readings per measurement channel.
Wireless temperature probes allow for temperature monitoring in diverse locations without the installation burden or cost of excessive wiring. In a free field, the typical transmission path of a wireless temperature sensor device is roughly 100 m at a frequency of 2.4 GHz. However, inside of facilities, the transmission path for wireless RF sensors may be influenced—and thus impeded—by structural elements in the pathway, such as equipment, walls, and metal doors. The use of one or more routers installed between the wireless devices and the base unit can improve the wireless link and/or extend the transmission distance by both amplifying the signal and acting as a repeater.
Hard-wired (Ethernet) temperature probes use a facility’s existing LAN structure and are more appropriate for applications that require longer data-transmission distances between the sensors and the base unit, or those that require longer periods of battery-free operation.
Testo Inc., www.testoUSA.com
This article appeared in the October 2012 issue of Controlled Environments.