MRI machines contain powerful super conducting magnets that are cooled by liquid helium. The storage and handling of liquid helium and liquid cryogen presents a safety hazard within the MRI environment. Helium is a colorless and odorless gas not directly detectable by humans. In the event of a cryogen leak the air and hence the oxygen in the room can be rapidly displaced by the helium or nitrogen gas thus reducing the ambient oxygen concentration and posing a suffocation asphyxiation hazard to personnel in the MRI room. For this reason it is recommended and often mandated that MRI rooms be monitored with an oxygen depletion (deficiency) monitor. The MIDAS O2 is designed for this purpose. It comprises a sensitive oxygen sensor and electronics package with a remote sensing system. The instrument must be located outside the range of the MRI magnetic field environment. The atmosphere is constantly sampled by a length of tubing that runs from within the MRI room to the instruments sampling port. The MIDAS O2 is self contained with a built in sampling pump alarm relays, and analog and digital alarm outputs. The unit is small in in size and its easy access metal chassis design makes it simple to install even when space is at a premium. The unit can be wall mounted using mounting points on the back of the chassis. An optional L bracket provides a free standing mount which can be secured to a horizontal surface. A duct adaptor is provided should it be necessary to connect the sample tube line into an air duct.
MIDAS O2 includes various power and communicationsoptoins as standard including 3 on-board relays, 4 - 20mA analog output, Modbus/ TCP Ethernet digital outputs, as well as the innovative Power over Ethernet (PoE) protocol - a single Ethernet connection for all power, control and communication requirements. It can be run as standalone alarm system or integrated with PLC and FieldBus systems.
MIDAS O2 offers lower cost of ownership benefits for increased MRI safety through a combination of extended sensor calibration periods, flexible communications architecture, and patented diagnostics that monitor sensor performance and flow control. MIDAS O2 will monitor points up to 30m (100 feet) away from the transmitter and flow rates are regulated automatically using patented control technology to ensure error free gas sensing operation.
For an MRI room, the sensor must be located outside to exclude any metals from the environment. A sampling pump draws air from the MRI zone and delivers it to the oxygen sensor. Cryogen leakage can cause rapid suffocation when concentrations are high enough to reduced oxygen concentration levels below 19.5%.Transmitter Dimension | (unit with Sensor) 120mm (H) x 63mm (W) x 150mm (D) | Weight: (unit with Sensor) 0.8Kg |
Power Requirements | Operating Voltage 24V DC Nominal +/- 10% | Operating Voltage with Power over Ethernet (PoE): 36 - 57 VDC via PoE, 48V DC Nominal |
Power Consumption | Transmitter Unit: ~ 5.0W | |
Outputs | Visual: Alarm, Power and Fault lights as well as back lit LCD display with all gas readings and events |
Relays: 3 relays for Alarm1, Alarm 2 and Fault rated 1.0A @ 30VDC or 0.5A @125VAC; configurable NO or NC, latched or unlatched |
Analog: 2 wire isolated, 0 - 22mA, Sink or Source | Digital : Modbus / TCP Ethernet / Power over Ethernet (PoE) | |
Service Port RS232C / PPP protocol | ||
Sampling Distance | Tubing Length: Up to 30m (100 feet) | Ambient Point Monitoring: In line air filter recommended |
Tubing Requirement | Exhaust Length Up to 30m (100 feet) | |
Sample: 6.35mm OD (1/4”) x 3.18mm (1/8”), FEP, 30m (100 feet) maximum dependant on gas type | ||
Operating Temperature | 0˚ C (32˚ F) to 40˚ C (104˚ F) | |
Wiring Requirement | 4-20mA/DC Power/Relays: 14 AWG Maximum | Digital: CAT 5 cable or equivalent, RJ45 connector |
Gas Concentration Display & Interface | Instrument: 4-digit alphanumeric display with separate measurement units, flow rate bar graph and other icon driven indicators. 4 button membrane keypad | Remote Interface: PC / PDA Internet Browser access via Ethernet or other Bus system |
Response Times | Flow Rate: 500 mL/min | Transport Time: 2 - 30 seconds maximum |
Warranty | Transmitter Unit: 1 year Sensor Cartridge: 1 year standard; 2 year with extended warranty program Expected Lifetime of Pump: >2 years |
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Certification & Specification | European: CE marked; meets EN 50270:1999 (Type2) and EN 55011:2000 Environmental: ETL approved UL 61010B and CSA-C22.2 No. 1010.1-92 Performance: Designed to meet with UL 2075 (pending 2004) Electrical: >IEEE 802.3af-2003 |