Figure 6. Damage to aluminum end-closure plates resulting from the 



implosion of a 4-inch-ID, 6-inch-long glass pipe at 16,900 psi. 



In order to answer these questions, specimens of different sizes were 

 provided with end-closure plates, which were drilled and tapped to receive 

 a high-pressure tubing connection. The specimens were then assembled, 

 filled completely with water, and the high-pressure connection brought 

 through the pressure vessel end closure (Figure 13). This line was then 

 connected to a graduated cylinder so that the fluid expelled from the 

 specimen assembly in response to increasing external pressure could be 

 measured. Figure 14 illustrates this setup. A graphic plot of the volume 

 change versus pressure for three 4-inch-ID x 6-inch-long glass specimen 

 assemblies is shown in Figure 15. 



Experimental data from testing 4-inch-l D x 6-inch-long glass pipe 

 in the manner just described showed the following: 



1. The net reduction of volume of the glass pipe, under an external 

 hydrostatic pressure of 20,000 psi, was approximately 40 ml or 3% of the 

 volume at atmospheric pressure. (The void space normally left in specimens 

 tested for critical pressure amounted to about 10% to 15%.) 



2. The critical pressure of glass pipes partially filled with water did 

 not vary significantly from those filled with air at atmospheric pressure. 



