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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 ...


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 ...


4

A pressure suit is a protective suit worn by high-altitude pilots who may fly at altitudes where the air pressure is too low for an unprotected person to survive, even breathing pure oxygen at positive pressure. Such suits may be either full-pressure (i.e. a space suit) or partial-pressure (as used by aircrew). Partial-pressure suits work by providing ...


3

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 of the way between equations (4) and (5) of that paper. (The paper is really about incompressible flow, this is just a warmup for the author). $$\dot{m} = {{\...


3

"... while minimizing the thickness of the end plate. I don't care about how much material I use." Those statements are in conflict with each other. If the end plate must be flat on the inside, you have constraints on the design. To reinforce the end plate without increasing thickness, consider a web of plates perpendicular to the end plate. If ...


3

The ball gathers velocity and when you decelerate it the inertia results in the development of forces that separate it from the cup. Basically the inertia force which is required to develop the deceleration exceeds the maximum force of the bond between the ball and the cup.


3

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.


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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 ...


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

A Hydraulic intensifier, also called booster, works by converting hydraulic power from a lower pressure input to a higher pressure output with lower volume (flow). Wikipedia A simple design is two connected pistons of different diameter. The lower pressure fluid is applied to the larger piston, the resulting force is transferred to the smaller piston which ...


2

The proposed system won't work, as the foot straps are too flexible to prevent the large deflection and rotation of the posts. Instead, you shall embed the posts into the foundation (not shown) below the grade.


2

Flow rate is directly proportional to the square root of pressure. So for any given orifice, all else being equal, $\frac{GPM}{\sqrt{PSI}}$ is constant. Technically PSI here is the pressure difference across the orifice, but with no backpressure only the input pressure matters. For an orifice rated 1.8 GPM at 90 PSI, $\frac{GPM}{\sqrt{PSI}} = 0.1897$. To ...


2

If you know the external diameter and orifice diameter, From Wikipedia the orifice plate equation : $$q_m =\frac{ C_d}{\sqrt{1-\beta^4}}\epsilon\frac{\pi}{4} d^2 \sqrt{2\Delta p \cdot \rho_1} $$ where: $C_{d}$ = coefficient of discharge, dimensionless, typically between 0.6 and 0.85, depending on the orifice geometry and tappings $\beta$ = diameter ...


2

The problems with the vacuum would be that the resulting force would always be less than 1bar times the cross-section. In a typical dampener the pressure of the N2 (or compressed air) is a few bars, which results in a much more compact cross-section. It is difficult to maintain a vacuum Even if you could create a vacuum, it is very difficult to maintain ...


1

This is a minor addition to Fred_dot_u's answer. Regarding the radial stiffeners the best shape for the stiffeners (minimizing the deflection for a given weight would be a stiffener with the following shape (in green). This optimization only makes sense if you have large production numbers, otherwise you can use plain rectangular profile for the stiffeners ...


1

Most car suspensions are based on a spring - used to be flat cart type but now most cars have coil springs. Some cars did go with a hydraulic suspension - early minis come to mind. If you really mean the shock absorber, or damper, then they can be pressurized and tend to use oil. Never seen a vacuum based system on trucks or cars but it might have been done -...


1

Of course we could go below freezing using absorption cooling. The question is who would want to. Lithium Bromide chillers is what I'm familiar with, and the temperatures they can produce is limited less by the chilled medium and more the properties of the LiBr solution. Using brine as the heat transfer medium is common when we need to use chillers below ...


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

Yes, if it's airtight, but I wouldn't say 'collapse'. The water on the left side will be suctioned in to compensate for the loss of volume of the right-side water disappearing to the bag.


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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 ...


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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.


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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 ...


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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 ...


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Technically pumps only control flow, not pressure. You probably understand this but I want to explain for anyone new. Couple of examples to show the point - Running the pump with the pump outlet open to atmosphere. Your pump pressure will forever be... 0 psi! Nothing resists the flow of liquid. No pressure will ever build up downstream. You could be running ...


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 ...


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Assume you were able to put uniform pressure each time on the dough, and assume the material property is uniform in all directions, then it is correct that the stress readings should be $W_1/A_1$ and $W_2/A_2$. However, the stresses will not be constant, unless $A_2 = 8*A_1$ (for $W_2 = 8*W_1$). In reality, the stresses will not uniform due to change in ...


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