PDPG-H Manual
Page 12
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cos
1
r
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⑥
Record the reference pressure value and UUT pressure value.
- At this point reference pressure means pressure value that total mass loaded.
- After finished measuring, if next measuring point is UP(pressurized), make a
piston position a bit lower then stop the piston rotates, repeat step
②
.
- If pressure is Down point, make a piston a bit higher then stop the piston
rotates, repeat step
②
.
2.5. Reference Pressure Calculation
▶
Basic Calculation : Add Bell+Piston Cylinder's pressure value with loaded masses
that pressure value marked on masses.
Ex) Basically Bell + Piston : 5 bar
If masses are as following, 45 bar 1ea, 50 bar 3 ea
Total pressure value is 5+45+50+50+50 = 200 bar
▶
Precision Reference Pressure Calculation
m
= T o ta l m a sse s lo a d e d o n p isto n
g
= L o c a l g ra vity
ρ
a
= A ir d e n s ity
ρ
m = M a s s d e n sity
γ
= S u rfa ce te n sio n co efficie n t o f O il (D o e s n ot a p p lie d p n e u m a tic )
C
= C irc um fere n ce o f p isto n (D o e s n ot a p p lie d p n e u m a tic )
A o = P isto n effe ctive a re a at sta n d a rd te m p e ratu re
λ
= P isto n -C ylin d e r p re ss u re c o effic ie nt
P n = N o m in a l p re s su re
α
p
= P isto n lin e a r th e rm a l e xp a n sio n co e ffic ie n t
α
c
= C ylin d e r lin e a r th e rm a l e xp a n s io n c o effic ie nt
T
= P isto n -C ylin d e r tem p e ra tu re
T r
= R efere n ce p re ss u re
(
ρ
f-
ρ
a )g h = H e a d co rre ctio n
