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19 votes

How fast does solid waste fall in vertical drain pipes?

This is not a factor in practice: Water (and entrained solids) directed into a vertical pipe segment adhere to the sides of the pipe. I.e., there is no free-fall in a vertical waste pipe. Rather, ...
  • 1,785
9 votes

What is the correct pipe size for a 2inch pipe?

As of the 2013 edition of ASME B16.5, the scope section explains: This Standard states values in both SI (Metric) and U.S. Customary units. As an exception, diameter of bolts and flange bolt ...
  • 4,501
9 votes
Accepted

How to seal a pressure vessel

I have done this before so would like to share some of what I know. Super critical CO2 has some unique properties, for one it is extremely difficult to keep in a closed container since it has near ...
7 votes
Accepted

Why prefer plain pipes over corrugated pipes for storm sewage and culverts?

You are correct in your assumption that corrugations give pipes strength and hence such pipes can have thinner walls that smooth walled pipes made of the same material when used for the same ...
  • 9,527
6 votes
Accepted

What is the correct pipe size for a 2inch pipe?

I would guess that the discrepancy is down to rounding fractional inch sizes to decimal inches ie 2.38 is not exactly 2 3/8" Note that 2.375 (two and three quarter eighth inches) is 60.325mm
  • 15.1k
6 votes

Water pump at top floor or bottom?

Think about the pressures. With the pump above the supply line, the pressure at the input of the pump will be lower than the supply. At roughly 2 PSI per foot, you're down about 18 PSI. Since air ...
  • 11.3k
6 votes
Accepted

Watering utility that does not spill

The water level in the lower basin will not exceed the level of the bottom of the bottle opening. When the empty device is loaded with a full bottle (by keeping the bottle upright!) and then inverted, ...
  • 6,427
5 votes

Force required to empty a syringe

You can get a minimum bound from energy balance alone. This is as if the fluid has no viscosity, so the force you have to apply over the distance is only due to the kinetic energy required to expell ...
  • 11.3k
5 votes

Why prefer any other pipes over plastic pipes for drainage and culverts?

Although it doesn't corrode in the same say that steel does, plastic also degrades over time. The common corrugated steel pipes are galvanized, so take some time to corrode. Concrete is usually used ...
  • 11.3k
5 votes

Why actuators are mounted in inverted position?

The cylinder will be mounted where it is easiest to get the hydraulic lines to it.
  • 4,933
4 votes

Pipe seized to inaccessible coupling - how to attach a new pipe?

The way of removing couplings in the worst case scenario, where all other alternatives has failed, is to physically destroy the coupling. Cut/grind 2 slots the entire length of the coupling on ...
  • 1,079
4 votes
Accepted

What is the name of the part that allows a steam wand to have a moveable joint?

It is called a "steam wand gasket". Technically, it's a ball-and-socket joint made out of two concave PTFE (Teflon) gaskets and an EDPM gasket for the seal. There may be other designs too; I learned ...
  • 5,960
4 votes
Accepted

Why is hydrotest pressure more than MAWP as per ASME Sec VIII Div 1

A Mechanical engineer, or some one who works in materials/reliability would be better suited to answer this, but I believe the reasoning to be the a combination of safety factor (ensuring fittings, ...
3 votes

How to bend iron pipe into a spiral guide rail for stair lifters

Cold bending steel, especially with a relatively thin wall, is difficult to do accurately. Typically the standard for custom parts like this is that the shape is close enough that the person ...
  • 4,501
3 votes
Accepted

What are these bent shapes on this elbow in a compressor suction pipe?

Notice that the "shapes" are in a right angled bend where the flow changes directions. Sometimes vanes are placed in right angled bends to reduce shock losses by reducing the turbulence of the flow ...
  • 9,527
3 votes
Accepted

Service Life of a Flashback Arrestor

The manufacturer says this about maintanence: annual testing of the non-return valve, body leak tightness and flow capacity is recommended WITT is happy to supply special test equipment ...
  • 4,651
3 votes
Accepted

How does a union joint with two male threads work?

Typically, most threads on pipes (in the USA at least) are male NPT and all the couplings or fittings are female NPT. You can connect two pipes with a coupling as long as the last pipe added is free ...
  • 7,499
3 votes
Accepted

Tube Strength vs Pipe Strength

Firstly, I assume that when you say "tube" what you mean is Hollow Structural Sections, and when you say "pipe" I assume that you mean typical scheduled pipe sections. In the US, the AISC Code ...
  • 490
3 votes

Tube Strength vs Pipe Strength

The advertisement referenced in the question was written by a liberal arts major without much of a clue what he was writing about. Pipe comes in certain diameters and wall thicknesses and threads ...
  • 5,932
3 votes

Given flow rate of an orifice at one pressure, how do I calculate flow rate for a different pressure?

Here is a reference from RoyMech, see section under "Orifice Flow Meter". The setup has the orifice placed in a pipe. Below is a similar, perhaps simpler, expression, from Jobson 1955, part ...
  • 1,367
2 votes
Accepted

Measuring pipe bolt torque without a torque wrench

I'm sure there are specific strategies relating to pipe flanges, but for the broader issue of controlling that all of your bolts are tight enough, here is some background information. When tightening ...
  • 4,501
2 votes

Measuring pipe bolt torque without a torque wrench

Although i know is's not the right answer, i would like to mention that using a micrometer to measure bolt length out of nut can be helpful, because that is proportional to torque, so for same ...
2 votes
Accepted

What tool does one use to inspect pipe bevel angles?

Based on your translation of 'root face' I'm assuming that the bevel they are inspecting is a bevel that has been prepared for a groove weld between two pipes. If that's the case, the typical ...
  • 4,501
2 votes

Water pump at top floor or bottom?

Considering this is a centrifugal water pump, it can provide very little air suction. That means if your pump is airlocked, there's not a shade of a chance it will be able to produce nearly enough ...
  • 6,133
2 votes

What is the difference between NPT and pipe diameter?

Pipe comes in different wall thicknesses, designated schedule 40, Sch. 80, Sch. 10, etc. Higher numbers are thicker walls. The outer diameter is the same for all schedules, so the inner diameter ...
  • 1,012
2 votes

Is there a way to reduce leaks and infrastructure damage when turning water on and off at the scale of city?

The problem with older and under-maintained (this is South Africa after all) systems is that the pipes get brittle, rusted and joints fragile and the network won't be able to handle the transient ...
  • 628
2 votes
Accepted

Is there a way to reduce leaks and infrastructure damage when turning water on and off at the scale of city?

It is difficult to provide a useful answer to this question without additional information. For example, what is the system pressurization - operating psi/bars? Having installed ductile iron water ...
  • 652
2 votes

Type and mechanism of piping fitting

The flange on the pipes are beveled and the groove in the clamp is V shaped. There is also a seal between the 2 pipes. As the clamp is screwed down it will force the 2 ends together. The dimensions ...
2 votes

Why does removal of ventilation of a sewage pipe lead to backflow from the toilet?

Simply if you remove the ventilation then you create a closed tube where the « piston » ie waste is trying to create a vacuum behind it, that is, untill it can draw past the liquid in the u-bend...
  • 14.2k

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