Double Valves

Common arrangements of two valves in series used both as traveling valves and as standing valves. Technical Data used in the field explained in petroleum courses in Rawalpindi. Experience has shown that two valves in series will give much longer service than a single valve if the valve life is determined by wear or fluid cutting, rather than by corrosive action.

This result appears entirely logical where sand or other solid material is lifted with the oil. In such cases failure is likely to occur as a result of fluid cutting when a solid particle is caught between the ball and seat and prevents perfect seating. A pressure differential of 2,000 psi will produce a jet of fluid having a velocity of over 500 ft/sec, which can easily damage the lapped valve-seating surface on balls and seats in a short time. The rate of damage is accelerated if the fluid jet carries solid material in suspension. Some more details of petroleum courses in Rawalpindi are as under.

The life of a ball and seat will depend largely on the number of times it is subjected to damage by fluid jets. By use of double valves this can be greatly decreased, since a jet cannot occur until both balls are held off their  seats during the same stroke. For example, if conditions are such that a single ball and seat is prevented from seating properly once out of each 100 strokes, the chances of both valves in series failing to seat properly will be reduced to 1 in 10,000 strokes. Furthermore, if the two valves fail to seat, the pressure drop will be distributed between the two valves and the cutting action will be less severe than with a single valve. TSK Training for Skills and Knowledge is the best institute in Rawalpindi Islamabad for Pakistani Students who wants to join petroleum courses in Islamabad.