Ball Valve Xt Value

The physics of choked flow in an ideal world there is a linear relationship between the differential pressure p and flow rate q as depicted by.

Ball valve xt value. The rated terminal pressure drop ratop xt of an 80 open globe valve. The tables below list the full cv vs angle closure and opening curves for various. The metric equivalent kv is the flow of water at 16 c through the valve in m 3 hr at a pressure drop of 1 kg cm 2. 70 q2h xg full bore ball valve trunnion mounted with q2h trim for noise abatement 71.

A valve s rated fl varies with the valve and trim style it may vary from 99 for a special multiple stage trim to 60 for a ball valve. Ball valves torque value data. To convert cv to kv multiply by 0 8569. A conventional ball valve is normally not used as a throttling valve since a partial flow will create high velocity flow tear at the ball and the seal.

But it says in the emerson control valve handbook that you should pick the xt value you think is appropriate. Let s see what would happen if we were to run the three flow tests listed in figure 4 using a typical globe valve with the inlet pressure p1 at first 100 psia then at 200 psia and finally at 1 000 psia. From what i can figure out you need the xt value to find the cv kv value. What i am struggling with is the xt value critical pressure differential ratio.

Gallons per minute at a pressure drop of 1 psi. The full closure curve of a ball valve is then the above graph multiplied by the valve s flow coefficient or factor. Ball valve flow coefficients c v flow coefficients c v for typical ball valves reduced and full bore. Make sure the values used match the trim and valve selected.

This graph shows the cv or kv valve fraction vs opening and closing angle of a full bore ball valve. In these equations x deltap p1 1 p2 p1 and x fk xt typical values of xt that i have found range from c a. I am trying to figure out how to get the correct valve size for a uni question. 4 metso control valve sizing coefficients.

Q2 xg full bore ball valve trunnion mounted with q2 trim for noise abatement. Value line 3 piece threaded and socket weld ball valves series 3a 3c. Lower than the valve s outlet pressure and the valve is more likely to cavitate. Connect sociialy with us.

Zhejiang xiongtai valve manufacturing co ltd was founded in 1998 is the largest valve manufacturers s long term commitment to the petroleum petrochemical natural gas hydropower thermal power and other fields of research and development of valves. 0 3 0 9 if we assume we are looking at air so the heat capacity ratio k 1 4 then fk 1 and x is totally dependent on xt. The flow of water at 60 f through the valve in u s. Value the lower the required cv to pass a given flow rate through a given orifice the converse is true as well.

If xt 0 9 then x 0 9 and flow through the valve becomes choked at p2 p1 0 1.