Abstract: According to at least one aspect, a fluid flow tube can define a first cavity for receiving a first ultrasonic sensor. The first cavity can have a first longitudinal axis intersecting a longitudinal axis of the fluid flow tube. The fluid flow tube can define a second cavity for receiving a second ultrasonic sensor. The second cavity can have a second longitudinal axis aligned with the first longitudinal axis. The fluid flow tube can define a third cavity having a first transverse cross sectional area larger than a second transverse cross sectional area of the fluid flow tube and sized to receive a shut-off valve.

Abstract: A fitting includes at least one port permitting flow of fluid and a connector body to which the port is attached. The connector body has a first mating portion. The fitting additionally includes a retainer structured to engage with the connector body and having a first tapered terminal portion and a second tapered terminal portion opposed to the first tapered terminal portion. The fitting further includes a tubular member configured to be fitted into the connector body and having a second mating portion structured to receive terminal portions of the retainer and configured to align with the first mating portion, and a seal positioned within the tubular member and disposed to be flush against an inner surface of the connector body.

Abstract: According to at least one aspect, a monolithic sensor mount can include a first cylindrical portion and a second cylindrical portion. The first cylindrical portion can have a first diameter and the second cylindrical portion can have a second diameter larger than the first diameter. The second cylindrical portion defining a recess region to host an ultrasonic transducer. The second cylindrical portion can have an outer surface that defines a male thread to mechanically engage a female thread of a cavity within a fluid flow tube configured to host the sensor mount.

Abstract: A fitting includes at least one port permitting flow of fluid and a connector body to which the port is attached. The connector body has a first mating portion. The fitting additionally includes a retainer structured to engage with the connector body and having a first tapered terminal portion and a second tapered terminal portion opposed to the first tapered terminal portion. The fitting further includes a tubular member configured to be fitted into the connector body and having a second mating portion structured to receive terminal portions of the retainer and configured to align with the first mating portion, and a seal positioned within the tubular member and disposed to be flush against an inner surface of the connector body.

Abstract: According to at least one aspect, a fluid flow tube can define a first cavity for receiving a first ultrasonic sensor. The first cavity can have a first longitudinal axis intersecting a longitudinal axis of the fluid flow tube. The fluid flow tube can define a second cavity for receiving a second ultrasonic sensor. The second cavity can have a second longitudinal axis aligned with the first longitudinal axis. The fluid flow tube can define a third cavity having a first transverse cross sectional area larger than a second transverse cross sectional area of the fluid flow tube and sized to receive a shut-off valve.

Abstract: According to at least one aspect, a monolithic sensor mount can include a first cylindrical portion and a second cylindrical portion. The first cylindrical portion can have a first diameter and the second cylindrical portion can have a second diameter larger than the first diameter. The second cylindrical portion defining a recess region to host an ultrasonic transducer. The second cylindrical portion can have an outer surface that defines a male thread to mechanically engage a female thread of a cavity within a fluid flow tube configured to host the sensor mount.