Infusion Pump

An infusion pump comprising

• a displacement sensor comprising:
• a detection surface, and
• a mask member comprising:
• a groove portion to which the detection surface is exposed and an infusion tube is attachable,
• a first mask portion that covers a first end of the detection surface in a width direction of the groove portion, and
• a second mask portion that covers a second end of the detection surface in the width direction of the groove portion,
• a Hall element, and
• a plunger that is movable with respect to the Hall element and comprises a magnet, wherein:
• the mask member is detachable from the Hall element and the plunger;
• wherein:
• the displacement sensor is configured to detect a pressure applied to the detection surface based on an amount of movement of the magnet with respect to the Hall element.

A method for using an infusion pump, comprising:

• providing the infusion pump, which comprises:
• a displacement sensor comprising:
• a groove portion to which an infusion tube is attachable,
• a detection surface exposed to the groove portion, the displacement sensor being configured to detect a pressure applied to the detection surface,
• a first mask portion that covers a first end of the detection surface in a width direction of the groove portion,
• a second mask portion that covers a second end of the detection surface in the width direction of the groove portion,
• a Hall element, and
• a plunger that is movable with respect to the Hall element and comprises a magnet;
• and
• detecting a pressure applied to the detection surface based on an amount of movement of the magnet with respect to the Hall element.