

FIC. 1a Complete parts and materials to construct electronic 

 tensionometer. VOM meter on right can be used to read output 

 (V ) of device. Parts and supplies are described individually in 

 text. 



FIC. 1b PVC threaded pipe union which serves as submersible 

 probe housing shown with brass insert containing Swagelock 

 fitting in which pressure transducer (LX 1601AF) is mounted. 



FIG. 1c Unit completed with approximately 30 ft of cable. R1 

 and R2 (see text) are on lower two corners of aluminum box; 

 switch (Si) is in center below readout (V D ) jacks. Hair curler 

 spool to hold silastic is shown without perforated metal protector. 



FIC. Id Same as 1C but with digital VOM meter connected to 

 output V . 



though not essential, to machine a part of the 

 Swagelock fitting insert to extend into the nipple 

 of the pressure transducer as shown in Fig. 2a so 

 it occupies most of the dead space of the pressure 

 transducer nipple. The other end of the machined 

 rod holds a 2 in. length of #25 hypodermic stock 

 to connect to the silastic tubing. Care must be 

 taken when constructing and assembling this part 

 of the unit to avoid the risk of stressing or punc- 

 turing the silastic fluid-isolating membrane of the 

 pressure transducer (Fig. 2a). 



The Swagelock fitting is screwed into a brass 

 insert (Fig. lb and 2a) which is constructed of 



1/8 in. plate 2-3/4 in. in diameter, soldered or brazed 

 to a 1 in. length of 1-5/8 O.D. brass bar stock which 

 has been machined to an I.D. of 1 in. to receive the 

 Swagelock fitting. 



This brass adapter fits inside a schedule 80 PVC 

 1-1/2 in. threaded plastic pipe union as shown in 

 Fig. 2a and 1d. Approximately 10 ft of silastic tube 

 is wound around a plastic hair curler (TipTop®) 

 #5840/X, Faberge Inc., Omaha, Nebraska) and one 

 end is tightly knotted and/or plugged with a short, 

 smooth length of nylon fishing line. The other end 

 of the silastic tubing is strain-relieved on the side 

 of the hair curler by a loose knot or RTV adhesive 



Electronic Monitor 107 



