Handheld probe for tube inspection using APR
Exemplary embodiments of a handheld probe (HHP) of an Acoustic pulse reflectometry (APR) system are disclosed. Embodiments of the HHP can comprise a loudspeaker and microphone that are vibration isolated from each other and from the tube under test. In some embodiments the microphone can be isolated from the housing of the HHP. In other embodiments the housing of the HHP can be isolated from the loudspeaker. In another embodiment the housing of the probe can be isolated from the tube under test. Yet, some embodiments combine all of this isolation options. In such embodiment the loudspeaker is isolated from the housing, the housing is isolated from the tube under test, and the microphone is isolated from the housing, and so on. Isolation can be achieved by using materials that absorb vibration, material such as but not limited to rubber, foam, silicone, etc.
1. A handheld probe (HHP) of an Acoustic pulse reflectometry (APR) system for measuring a tube under test, the HHP comprising:
a. a rigid housing having a tunnel along the housing from an egress end of the housing;
b. a microphone inserted in a wall of the housing;
c. a loudspeaker associated with the ingress end of the housing via a first vibration absorbing ring (VAR);
d. a short interface tube (SIT) associated with the egress end of the housing via a washer wherein the diameter of the ingress orifice of the SIT fits the diameter of the egress of the rigid housing and an egress section of the SIT is adapted to be entered to ingress of the tube under test; and
e. an assembling mechanism comprising:
a threaded retainer that associate the SIT with the housing;
a second VAR located on the other side of the loudspeaker so that the loudspeaker is held between the first and the second VAR;
a support metal ring on the other side of the second ring; and
a plurality of pressuring elements that push the housing against the support metal ring to associate the components of the HHP into a single device; and
wherein, an orifice defined by the first VAR, the tunnel of the housing, an orifice defined by the washer and the SIT form an opening between the loudspeaker and a tube under test and between the microphone and tube under test for reflected acoustic waves return from the tube under test.
2. The HHP of claim 1 , wherein the microphone surface substantially flush with the internal surface of the housing.
3. The HHP of claim 1 , wherein the first VAR is made of rubber.
4. The HHP of claim 1 , wherein the rigid housing having, at its ingress orifice, a recess that carries a thick ring made of open cell foam.
5. The HHP of claim 1 , wherein the SIT having, at its egress orifice, a recess that carries a thick ring made of open cell foam.
6. The HHP of claim 1 , wherein the vibration are acoustic vibrations.
7. The HHP of claim 1 , wherein the microphone is isolated from vibrations that are transferred in the wall of the housing.
8. The HHP of claim 1 , wherein the pressuring elements are a plurality of screws that pass between the housing and the support ring, wherein the middle of each screw shaft is smooth.
9. The HHP of claim 1 , wherein the egress section of the SIT has a Diameter smoother having a plurality of openings around its wall.