24

TL;DR: Its not the air that's enclosed inside that creates the force, but the lack of air - or more precisely pressure. First of all some nomenclature (this is for the closed type, there is also the open type): When you press a suction cup on a surface what happens is that the air inside it is pushed out. During the compression phase of the cup the air ...


6

The yellow curve corresponds to a fan that will provide mostly a set pressure differential, say, keeping fumes from escaping a tank through elsewhere than dedicated vents. If there is a circumstance that reduces the pressure differential, it will speed up and increase the flow, to compensate. The blue curve is a fan that doesn't expect any significant ...


6

The idea that I was describing in the comments earlier is pretty similar to that described by Mart - I imagined the tube (red) flaring out underneath the O ring, and the opposing taper being either pushed down by hand or driven by a standard nut (black) depending on the sealing forces required. The key difference is that instead of relying on the squashing ...


5

Don't do it!! Just buy a pressure regulator to put between the two tanks that will decrease the pressure to below 125. You can get these for \$17 at home depot (https://www.homedepot.com/p/Husky-1-4-in-NPT-Regulator-with-Gauge-41155HOM/205331831) and maybe even cheaper elsewhere. I'm terrified of the tank exploding and covering me with shrapnel. This is a ...


4

You could have a barely undersized O-ring around the nozzle, then use a thread around the nozzle to press on the O-ring with a nut. This would require to machining a custom nozzle and nut: The part of the nozzle where the O-ring rests and the machined part of the nut should probably be larger than in the drawing, 4.5mm or so. I would also consider a ...


3

There is a better way sometimes used for ponds. It avoids the large maintenance job you will have cleaning the inlet to your pump. Dig out an area for pond and wetland. Lay a good size (like 4") plastic pipe from far end of wetland to far end of pond. Put in liner or what you are using to prevent water from soaking into the ground. Build a porous wall ...


3

The problem is that when you are inside the submarine you usually get more or less normal atmospheric pressure (maybe a little higher). What keeps the submarine from imploding is the structural resistance of the hull (usually an inner and an outer hull). The water pressure at the Challenger deep is in the order of 1100 bar (8 tons per square inch). So if you ...


3

Here are the limitations to this approach. First of all a howitzer is specifically designed for relatively short-range use, by using a very steep (in some cases, almost vertical) launch angle which allows the howitzer projectile to be lofted high up above trees, buildings, and even hilltops and then strike the intended target by falling almost vertically ...


3

In industrial settings, the correct piece of equipment is referred to as either a Pressure Relief Valve (PRV) or Pressure Safety Valve (PSV). These are spring-loaded valves with a few specific characteristics The valve is designed with a spring load, and is ordered with a relief pressure in mind (in your case, 120 PSI) the valve is sized with a valve ...


3

I understand your setup as follows (in flow direction): compressor with cutout set to 150 PSI tank (T1) rated for compressor, with safety valve (planned) pressure regulator (PR) additional tank (T2), rated 120 PSI, with safety valve If this is so the safety valve of the second tank will protect you unless you tinkered with or replaced this safety valve. ...


2

Figure 1. A typical aerosol valve. Source: Wikimedia. An Internet image search will show that most aerosol valves are of the type shown in Figure 1. Here it should be clear that if the differential pressure across the valve is reversed (pressure inside < pressure outside) that the valve will tend to open. The internal spring opposes the opening and so ...


2

The valve on such a can may be engineered to resist internal pressure in such a way as to seal when the can's contents are in place. If the can is completely empty and placed in a vacuum chamber, it's possible that you can evacuate any additional gases within, but once the vacuum is removed, the can will "suck" in air until at near-ambient pressure.


2

A 10 or 25 psig overpressure of a tank is well into a potential failure for the tank. The 140 psig safety valve is used because that accounts for the true pressure capability of the tank plus the tolerance in lift pressure for the safety valve. If you replace it with a 150 psig valve, you are risking the tank building up pressure past it's breaking point to ...


2

The nyloc nuts come to mind... but sealing well around a thread will be a challenge. But why not keep a piston on the end of the thread in a cylindrical bore so the piston seals well on the bore and it is driven with a screw thread? Or just use a classic crank mechanism.


2

When you push that onto a flat surface it pushes most of the air out. The elasticity of the item makes want to flex and come off but the air pressure is pushing it onto the surface.


1

Screw threads and nuts have to be made with clearance between their sliding surfaces to allow them to rotate without getting jammed stuck. If you try to use the head end of a threaded rod as a piston, the liquid you are trying to pressurize will ooze back through the clearance space and leak away. As pointed out by Solar Mike, there are types of threads ...


1

It might help to consider the special case of Hatton's excellent answer, where the velocity is very small. A small piston at one end of a tube, then an expansion to a large piston at the other end, is an idealised hydraulic jack. When not moving it is considered to have the same pressure at each end, so can support a car at the large end with a small force ...


1

The static pressure is the compressive longitudinal stress exerted by the pipe walls on the fluid and vice versa, but perhaps more importantly in this context, it is also the compressive longitudinal stress exerted on every little parcel of fluid by the parcels of fluid next to it, in every direction. If the pressure didn't decrease along the length of the ...


1

Is there a problem with the standard isothalic polyesther resin ? It is used for high strength sucker rods and most other things. Nearly all the strength is in the glass. For pressure tightness add a surface gel coat.


1

It's straightforward to model very slight deformation of the sphere (i.e., slightly flattening its surface). It's also pretty straightforward to model the case when the sides are already fully flattened and meeting at the corners. It's trickier to bridge the gap. The small-deformation case has an exact solution for a single side (Case 2 here): the ...


1

It is incorrect to imagine there is very little pressure being applied to the submarine from beneath it. To a stationary submarine, the pressure it experiences is nearly identical at all points on its surface. The difference in pressure will be the incremental pressure increase due to the depth of the water increasing as you go from the top to the bottom of ...


1

According to New Atlas, a solar power plant went online in 2009. The principles are similar to your diagram, but simpler. Mirrors (not lenses) redirect sunlight to a single point atop a tower, which converts water to high pressure steam. The steam is used to spin turbine generators, located on-site. The expended steam is thereby cooled and condensed and used ...


1

Purchase a proper footswitch unit. You need to decide your specifications: Momentary action or latched. Normally open (NO), normally closed (NC) or changeover. The latter gives you options. Program your microcontroller with a pull-up on the input. Wire your switch from the input to ground so that it pulls low when pressed. You might need to debounce your ...


1

you take the difference because the force due to pressure acting on the top surface has direction upwards, while the force on the bottom surface has the opposite direction (same direction as gravity). So the two forces cancel each other. Becauce the $F_{top}= P_{Ext}\cdot A_{top}$ and $F_{bot}= P_{Ext}\cdot A_{bot}$ the net force is: $$F_{net}=F_{bot}- F_{...


1

This is the essence of the ASME Boiler Code ;allowable stresses for materials at various temperatures. It is NOT a calculation . It is based on a great many creep and stress rupture tests which have been analyzed and reviewed for over a hundred years.If you are building a pressure vessel in the civilized world ,it is required to conform to "code" , ...


1

If the pressure in the dome stays constant at 2 atm this implies there is some pressure relief mechanism so the volume is not fixed. Therefore there is no work needed to compress the air in the system any further. If the weight and friction of the object are negligible as well, there is also theoretically no additional work needed. Work is force x distance, ...


1

So if the vessel is rectangular , I assume a flat heads, essentially no different than a side. So the size of sides and heads would determine the necessary thickness. In traditional cylindrical pressure vessels the stress is reduced by about half in domed heads , so they may be thinner .


1

Without storing the soda in bags, I think you will struggle to find a solution that works better or even at a lower cost than the syrup & carbonated commercial solution. Mechanical check valves are not going to work well enough at the very low pressures we'll find here. and solenoids just complicate a system that I assume you are trying to keep simple ...


1

Add air or C02, using a pump,to keep the contents above atmospheric pressure or at the pressure of the soda bottle. Not sure what that is as I have never measured it, but some seem to be significant and they can push out quite a bit of the contents. That means you will need two barbs to the lid. Consider making special lids - perhaps out of brass or ...


1

Listen to your Dad. A flexible hose requires a minimum water pressure to maintain the characteristics required for all of the above factors. A 100' hose will see a significant pressure drop at the outlet, and a flexible hose will have some level of contraction if the source pressure is not high enough, which invalidates all of the assumptions. I have filled ...


Only top voted, non community-wiki answers of a minimum length are eligible