Common MRI failures fall mainly into two categories: patient table advancement faults and water chiller unit faults.
MRI patient table advancement faults
During patient loading, several problems can occur at the table advancement stage and affect the scan.
1.1 Table height mismatch
Symptoms: the table height does not match the specified entry height for the MRI system. This causes uneven tilting and irregular movement during table advancement. The table rubs and produces noise. If irregular tilting continues over time, friction becomes severe and the table may eventually lose normal height adjustment.
Causes: incorrect table height parameter settings during equipment commissioning, or mechanical deformation and damage to the table structure that prevents it from reaching the specified height.
1.2 Table enters but cannot exit
Symptoms: the table can enter the scan area normally but cannot retract.
Causes:
The belt that controls table movement is damaged, such as aging or breakage, so it cannot drive the table properly.
An object dropped by the patient jams the belt and blocks its rotation, affecting table movement.
The belt is damaged or detached, causing the table entry and exit function to fail.
1.3 Blurred head scan images
Symptoms: during head scanning, images are blurred, while images of other body parts are relatively clear.
Cause: the cable on the head coil is worn. Coil performance drops, and it cannot accurately receive and transmit signals. The head images displayed by the imaging system appear blurred.
For MRI manufacturers and authorized service providers, Hansheng Automation can machine custom non-magnetic table drive parts, coil housings, and water chiller fittings to customer drawings in single units or small batches.
Water chiller unit faults
The water chiller unit on an MRI scanner is critical to normal operation. Its faults mainly appear in the following two areas.
2.1 Refrigerant charging problems
Symptoms: in spring and summer, when the average water temperature is above 20°C, the water temperature remains high after refrigerant is added. The MRI system cannot cool properly.
Causes:
The amount of refrigerant added is inaccurate. Too much or too little can affect cooling performance.
The refrigerant quality is poor, such as containing impurities, which affects refrigeration performance.
The heat dissipation system of the water chiller unit has a fault and cannot release heat in time, so water temperature rises.
2.2 Internal water tank freezing in the water circuit
Symptoms: the internal water tank in the water circuit freezes. Water circulation fails, affecting MRI cooling.
Causes:
The temperature control system of the water chiller unit has a fault, causing water temperature in the tank to become too low and freeze.
Water quality is poor and contains excessive impurities or minerals, which tend to freeze in low-temperature environments.
The water chiller unit operates in a low-temperature environment for a long time without effective antifreeze measures, causing the tank to freeze.
Periodic inspection of the magnet cooling system
To reduce failures and lower equipment operating costs, perform regular inspections of the magnet cooling system.
Cold head inspection: check whether the cold head is running continuously and whether the cold head motor makes abnormal noise. If the cold head stops running or the motor makes abnormal noise, the cold head may have a fault and needs timely repair or replacement.
Helium compressor inspection: check whether the helium compressor is running continuously, whether working pressure is sufficient, and whether the historical records contain error messages. If the helium compressor stops or working pressure is insufficient, magnet cooling is affected. Find the cause and address it promptly.
Water chiller inspection:
Check whether the water pump runs normally and whether the filter needs cleaning or replacement. If the pump stops or the filter is clogged, water circulation is affected and cooling performance drops.
Check whether the compressor is cooling and whether refrigerant pressure is sufficient. If the compressor does not cool or refrigerant pressure is insufficient, chiller cooling performance is affected. Add refrigerant or repair the compressor as needed.
If the water chiller stops working twice due to compressor freeze alarms, cooling water cannot cool the helium compressor, helium temperature becomes too high, the helium compressor stops, and the cold head stops. Check the external water chiller carefully, clear the alarm, let the compressor continue working, and restore the system. If the helium compressor and cold head have faults, contact the manufacturer for repair as soon as possible to reduce losses.
MRI maintenance is highly specialized. Service engineers need to keep improving their professional skills and strengthen their sense of responsibility. When equipment faults occur, think carefully, communicate with peers, avoid blind actions, and do not easily overlook faults that can be resolved, so as to avoid unnecessary losses.
Beyond MRI components, Hansheng Automation also machines custom precision parts for respiratory support equipment, compressor assemblies, medical devices, filling machinery, printing equipment, tobacco packaging machinery, yacht hardware, and RC car structural parts. We work from customer drawings and deliver single units or small batches. The service remains focused on precision parts manufacturing, not complete equipment sales.
