Manifold design

Please tell us the pressure involved, the pipe size of the manifold, and the sizes and spacings of the branch pipes off this manifold. I don't think there is any one simple formula for this, especially without these details.

1. The discharge capacity of each pump is 2417m3/hr.

2. No of pumps involved is 2working +1 standby.

3. The c/c to c/c distance b/w the delivery pipe is 4m.

4. The assumed time for filling manifold is 15sec. Based on that the size of manifold assumed is 2m dia X13 m length.

4. The (VT) pump head is 108m. The max surge pressure that develops in side pump house is around 327m. The rating of valves inside pump house is 24kg/cm2 with test press of 36kg/cm2.

5. The max surge pressure that occurs in transmission pipe with air vessel protection can be taken as 162m.

Hope the data provided are in line with ur requirement.

This is helpful information. The manifold is large enough that it may need to be considered as a pressure vessel, depending on the local code requirements. I usually work in non-SI units, and this system is larger than my experience. Thus I won't try to design it, but I can describe some of the process.

The 2m manifold pipe must withstand the given 162m of pressure, which will dictate its initial thickness. 162m = 230 psi; 2m = 74 in; t = 230 x 74 in /(2 x 13,750 psi) = 0.619 in. = 15.72 mm. Select 20 mm thickness for trial.

2417 m3/h = 10,675 gpm. I don't know the discharge pipe size from each pump, but I saw a pump online for 11,000 gpm with 16 in (400 mm) discharge. Will you stay at that size until entering the manifold, or will you increase to say 450 or 500 mm?

When that is decided, we can address whether the pipes will need reinforcement pads where they attach to the manifold.

Also, what is the fluid? This may affect the question of corrosion allowance.

Thanks a lot for ur valuable response.

The dia of delivery pipe connecting to manifold will be 800mm.

The type of fluid is raw water.

Can u also tell the reason why it has to be done as pressure vessel.

The problem is the stress concentration where several tubes do come together. Best approach is to start with pipe wall thickness and make a FEA analysis.