Support on Pressure Vessel

Type of support used depends on the orientation and pressure of the pressure vessel. Support from the pressure vessel must be capable of withstanding heavy loads from the pressure vessel, wind loads and seismic loads. Pressure on pressure vessel design is not a consideration in designing support. Temperature can be a consideration in designing the support from the standpoint of material selection for the different thermal expansion.
Various types of support that is used to support the pressure vessel are as follows:
 Saddle support
 Support Leg
 Lug support for
 Support Skirt

a. Saddle Support
Horizontal pressure vessel is generally supported by two advocates of saddle support. Wide saddle support the weight of the ultimate burden on a large area on the shell to prevent excessive local stresses on the shell above the supporting point. The width of the saddle between the detail design is determined based on the specific size and condition of the pressure vessel design.




Pic 2. 7 Pressure Vessel Horisontal with Saddle Support

One of the saddle support of a normal fixed or anchored at the foundation. Meanwhile, other supporters are free to permit normal thermal expansion longitudinal uncontrolled on a vessel.

(1) Saddle Design
Methode designs from a proponent of the horizontal vessel based on an analysis of Zick LP issued in 1951. )
The weakest part in the saddle should be able to withstand a force hosizontal (F). An effective part in the saddle to hold the load is one third of the radius of the vessel.



Pic 2. 8 Gaya Horisontal on Saddle Support



Table 2.3 Value Constant K11 )



Minimum contact angle suggested by the ASME Code is 120o, except for a very small vessel.

(2) Stress on the vessel at the second saddle
Stresses that occurred on the vessel which is supported by two saddle disubyekkan at:
• Longitudinal bending stress
• Tangential shear stress
• Circumferential stress



Pic 2. 9 Pressure Vessel Horisontal support by 2 Saddle


Table 2. 4 Value Constant K )
K1 = 3.14 if the shell is stiffened by ring or head (A< R/2)



Value Constant K6 Can see on attachment


A) Longitudinal Bending Stress
The maximum bending stress (S1) can occur in one of two voltage occurred, ie tensile stress or the press.
To calculate the tensile stress S1 in the formula, use the K1 factor to the value K. To calculate the compressive stress at the formula S1, K8 to use the factor value K.

 Stress in Saddle



 Stress at Midspan



In tension, the sum of S1 with internal voltage pressure (PR/2ts) must not be greater than the voltage of the material permits the shell multiplied by the efficiency of the connection.



(B) Tangential Shear Stress
If the wear plate is used, the formula for the thickness ts S2 can be taken the sum of the thick shell and thick wear plate, wear plate given extended R/10 inches above the tip of the saddle near the head and extend between the saddle and the adjacent ring stiffened.

 tangential shear stress on the shell
If A> R / 2





Jika A ≤ R/2




Use the formula with a factor of K2 when not using the ring or ring adjacent to the saddle.
Use the formula with the K3 factor when using the ring on the saddle.

 tangential shear stress on the head



S2 should be no greater than the voltage value of materials allowed on the vessel multiplied by 0.8.
(C) Circumferential Stress
If the wear plate is used, the formula for the thickness ts S4 can be taken the sum of the thick shell and thick wear plate. given extended wear plate R/10 inches above the tip of the saddle and A ≤ R / 2.
If the wear plate is used, the formula for the thickness ts S5 can take the sum of the thick shell and thick wear plate. The width of the wear plate which is given less or equal to.
 Bending Stress around the edge of the Saddle:
If R then L ≥ 8;



If L < 8 R so;





S4 should be no greater than 1:50 is multiplied by the value of the allowed stress of the vessel material.

 Circumferential Bending Stress at the bottom of the Saddle:





S5 should be no greater than 0:50 is multiplied by the value of yield stress of the material vessel.

b. Leg Support
Small vertical pressure vessel (see figure 2.10) are generally supported by the dilaskan leg at the bottom of the shell. Comparison between the maximum length of the support leg with a diameter of vessel is usually 2:1. Ring reinforcement pad or pad dilaskan first shell to provide additional reinforcement of local and load distribution, where the local stresses that occur shell can be overdone. The sum of the leg is needed depends on size and weight received vessel. Support leg is also commonly used in pressurized spherical storage vessels.




Pic 2. 10 Pressure Vessel Vertikal Supported by Leg

Support leg for a small vertical vessel or pressurized spherical structur storage vessels made from steel columns or pipes.

c. Lug Support
Lug a dilaskan the shell pressure vessel (see figure 2.11) can also be used to support the vertical pressure vessel. Use lug limited to a small vessel with a diameter of up to medium diameter (10-10 ft). with a ratio of height to vessel diameter is 2:1 to 5:1. Lug often used to support vessel located on top of steel structures. Lug usually bolted on the horizontal structure to provide stability against the loads, however, bolt holes are often given the gap to provide radial thermal expansion of freedom in the vessel.




Pic 2. 11 Pressure Vessel Supported by Lug

d. Skirt Support
Vertical cylindrical pressure vessel is high (see figure 2.12), generally supported by the skirt. Skirt support is part of a cylindrical shell dilaskan one of them at the bottom of the body vessel or the bottom head (for the cylindrical vessel). Skirt for dilaskan spherical vessel on the vessel closer to the center of the shell.



Figure 2. 12 Pressure Vessel vertikal Supported by Skirt