A fluid flow sensor , the sensor comprising: an ultrasonic transmitter configured to emit ultrasonic signals through an emitting face; and a pressure sensor configured to detect pressure changes through a receiving face; wherein the emitting face of the ultrasonic transmitter is spaced apart from the receiving face of the pressure sensor to collectively define a gap configured to receive a fluid delivery conduit therein; and wherein the pressure sensor comprises: a pressure sensing element mounted to a substrate and configured to sense the ultrasonic signal from the ultrasonic transmitter and to detect when at least a portion of the ultrasonic signal is deflected by a bubble flowing through the fluid delivery conduit before being sensed; and a force transmitting member positioned adjacent to the pressure sensing element , wherein the force transmitting member transmits a force arising from a change in fluid flow rate within the fluid delivery conduit applied to the front side of the force transmitting member to the front side of the pressure sensing element such that it is sensed by the pressure sensing element , wherein the force transmitting member is a gel; wherein at least a portion of the fluid delivery conduit positioned within the gap is compressed such that all of the receiving face of the pressure sensor is in contact with a portion of the fluid delivery conduit . an ultrasonic transmitter configured to emit ultrasonic signals through an emitting face; and a pressure sensor configured to detect pressure changes through a receiving face; wherein the emitting face of the ultrasonic transmitter is spaced apart from the receiving face of the pressure sensor to collectively define a gap configured to receive a fluid delivery conduit therein; and wherein the pressure sensor comprises: a pressure sensing element mounted to a substrate and configured to sense the ultrasonic signal from the ultrasonic transmitter and to detect when at least a portion of the ultrasonic signal is deflected by a bubble flowing through the fluid delivery conduit before being sensed; and a force transmitting member positioned adjacent to the pressure sensing element , wherein the force transmitting member transmits a force arising from a change in fluid flow rate within the fluid delivery conduit applied to the front side of the force transmitting member to the front side of the pressure sensing element such that it is sensed by the pressure sensing element , wherein the force transmitting member is a gel; wherein at least a portion of the fluid delivery conduit positioned within the gap is compressed such that all of the receiving face of the pressure sensor is in contact with a portion of the fluid delivery conduit . a pressure sensing element mounted to a substrate and configured to sense the ultrasonic signal from the ultrasonic transmitter and to detect when at least a portion of the ultrasonic signal is deflected by a bubble flowing through the fluid delivery conduit before being sensed; and a force transmitting member positioned adjacent to the pressure sensing element , wherein the force transmitting member transmits a force arising from a change in fluid flow rate within the fluid delivery conduit applied to the front side of the force transmitting member to the front side of the pressure sensing element such that it is sensed by the pressure sensing element , wherein the force transmitting member is a gel; wherein at least a portion of the fluid delivery conduit positioned within the gap is compressed such that all of the receiving face of the pressure sensor is in contact with a portion of the fluid delivery conduit . <EOS>