Welding apparatus having a safety feature

A welding apparatus having a safety feature, comprising:

• two electrodes, whereof at least one of said two electrodes is movably arranged in relation to the other electrode, said two electrodes are in non-contact with each other and define a gap in which an object to be sealed and having an electrically non-conductive surface may be inserted,
• an actuator configured to move said movably arranged electrode when activated, so as to squeeze the object when inserted in the gap, and
• an energy source configured to provide energy to said electrodes to perform a welding procedure,
• wherein said welding apparatus further comprises at least one of:
• 1) a detector configured to determine a clamping force when the inserted object is squeezed between the electrodes,
• 2) a distance sensor configured to measure the distance between the electrodes when the object is squeezed,
• 3) a conductance sensor configured to measure the conductivity of an object located between the electrodes when the object is squeezed,
• and optionally
• a position sensor configured to detect the position of the object inserted between the electrodes,
• and in that the welding apparatus comprises
• a processor configured to process the input from at least one of the detector, the distance sensor and the conductance sensor to provide an output that indicates if there is a blood bag tube inserted between electrodes, or if it is a foreign object;
• wherein
• the processor comprises a memory storing threshold values for distance, and conductance in memory, whereby the output from the processor is a comparison of sensor outputs with the stored threshold values;
• and wherein
• the processor comprises a memory storing clamping force profiles for various material types, whereby the output from the processor is a comparison of detector output with the stored profiles.