Unclesyd,
For your first question, if the PSV opened then the unit would shutdown on high discharge pressure. Once the unit is shutdown, the valve would open but by that time the pressure should be low because the PSV is relieving at the same time.
This is the original piping configuration...
All,
Please refer to the attached picture of a "T" with class 150 flanges. This piping system is connected to the discharge of a natural gas compressor. Connected to the inlets of the "T" are a relief valve and control valve. On the exit side of the "T" is piping which is connected to a...
dcasto,
Thank you for your explanation, very very helpful. The reason I was questioning this, is because the chromatograph also tells me that the cricondentherm temperature is at 5 degF at 319 psia. Using the GCAP software, the cricondentherm temperature is not what the software computes...
All,
I have been using GCAP8.2 equation of state software to develop phase diagrams to determine if liquids are dropping out of a natural gas stream. The gas composition has been entered into the software and a phase diagram is produced. It also produces two additional curves for hydrate dew...
All,
Thank you in advanced for the help/advise. I have a situation where the fuel gas used by the compressor units is coming from either the discharge side (1008 psi @ 98-120degF) or the suction side (700 psi @ 58-68 degF) of the pipeline. Typically the fuel gas is ran from the discharge side...
Sorry I do not follow your suggestion but thank you for replying and writing down the definition of stress.
-- Contact pressure calculation --
After several days of research, to calculate the bearing crush contact pressure, you can assume an interference fit pressure calculation of a bushing...
Sorry for the long over due post but I wanted to finalize the information so that it could help someone else with this problem. I contacted the company that used the coupling and stud combination. I finally got a mill spec. on the coupling material. The yield strength for the coupling was...
All,
Been on the road again, sorry for the delay. I think you guys a lot for your contributions. After looking at the failure several times, and Mark's comments on the studs touching at interface makes more sense. At the break interface, the threads are broken in the valley, which is the...
Background
The foundation under a large reciprocal compressor was cracked due to years of fatigue. This foundation was replaced by jack hammering the old foundation out. During this process the old stud was cut which mounted the engine to the old foundation and a new coupling-stud was used...
Sorry guys,
I have been on the road. More details. The heavy hex nut is a "coupling". One end is threaded onto an existing stud and then a new stud is threaded into the opposing end. A torque value of 2500 ft-lbs was recommended to impose a 40,000 psi pre-stress on the coupling. The nut...
All,
I have a heavy hex nut approximately 3 inches in size which was threaded onto a 1.75" diameter coarse thread stud; Grade B steel. It is about 5" long. The nut failed under a pre-stress of 40,000 psi. Due to dirt or some other means the nut also experienced some torque applied by the...
All,
Has any one heard of the Weymouth equation being used in conjunction with some type of Pressure Multiplier?
Weymouth Equation:
Q=433.49*(Tb/Pb)*D^2.667*E*SQRT[(P1^2-P2^2-Hc)/(L*G*T*Z)]
CJKruger,
1) Wouldn't the pressure at the exit be atmospheric?
2) So for a small valve in a system purge situation the ANSI equation is alright to use. Why is it NOT alright to use the ANSI equation on a blow down situation?
3) How would you calculate this effect or would you have to model...
CJKruger, can you tell me if I am understanding you correctly. Instead of concerning myself with the Cv rating of the valve, and valve properties. Since it is choked flow at the end of the pipe anyway, just use that cross sectional area and the mass flow equations used at air-dispersions.com...
BigInch,
Thanks for the link, may be handy in the future.
CJKruger
This is an emergency blowdown valve. On the inlet side of the valve there is only about 50 feet of pipe which is connected to a series of pipes (i.e., compressors, etc...). In the case of an emergency, this valve is opened...
Could someone verify that I am doing this correctly. The number calculated seems excessive. I am new to the industry and have been looking over equations and have nothing to compare my answer. In advance, I appreciate the help.
Problem Statement: An 8" nominal Rockwell dynamic balance plug...