Why does a spray bottle work?
alexanderellis.github.io
alexanderellis.github.io
Instead of a normal plastic tube inside a bottle with an opening at the end, he designed a tube with millions of tiny perforations along its length. This meant the spray bottle could operate at any angle (even upside down) and could empty all liquid in a bottle with no leftover.
Here is a 1 min demo of the spray: https://vimeo.com/195318537
Here's an explanation of how it works https://www.youtube.com/watch?v=xXk46rvzdpY
And here's the original pitch he made on Dragon's Den https://www.youtube.com/watch?v=RjOvyjeZyIw
In a business that operates at a scale of 100s of thousands if not millions of bottles sold annually, cents matter and can make up a significant portion of revenue.
With this in mind, there is a huge incentive to get people to buy sooner rather than later and more often. Forcing a small amount to remain in a used up bottle is definitely a benefit to the company even if the product is going to waste. This doesn’t include the cost of implementing something new. I’d imagine a company would do extensive survey based research to understand if the additional customer satisfaction would outweigh the costs/downsides.
If it’s not a conscious decision, it’s a nice coincidental benefit to them.
They have teams that actively engage with new suppliers and inventors and are also getting pitched constantly with new ideas. It's most likely that extensive testing and consideration showed that this wasn't worth the costs. You even described such a scenario so I'm not sure why you think that's stupid or apathetic, when it's actually quite calculated.
Business benefit supersedes customer benefit. Always.
Potato chip companies reducing the quantity of chips in a bag but keeping the size and price same. Because they were unable to raise prices with older packaging. Typically customers didn’t look at weight, just size of package. It was in the news for quite a while and IIRC there is a business case study.
It has been happening in beverages and other items too. Why do you see now package weights of odd numbers like 11.5 or 14.5 oz instead of standard number like 12 oz or 16 oz with typically no price reduction.
Recently I encountered same behavior with toothpaste tube in Japan. To keep the form/shape of the toothpaste tube with usage the nozzle was designed to suck in air to fill new space in the tube. My wife claimed we are out of toothpaste and wanted to throw away the tube. The toothpaste tube was perfectly formed but I noticed tube was still little heavier than I would expect for a empty plastic tube. But when you squeeze the tube mostly Air was coming out with little bit of spray of paste. Reducing the air space with paper clip, we were able to use paste from same tube for another 2 weeks. Typical behavior would be most probably what my wife was going to do to throwaway old one and open a new one.
In other words, if this costs 5¢ more then it is worth spending an extra 5¢ on if you keep from throwing at least 5¢ of product out. Below this it is better to throw a little product away. (However, consumers might overvalue being able to use the last little bit of product. Perhaps they value at 25¢ to not throw the last 1/30th of the product away, even though they paid less than $7.50 for the whole package. i.e. perhaps they paid $5.00 but would pay $5.25 to keep from throwing away the last 1/30th of the product. However this seems unlikely!)
More likely, if it costs 25¢ it is more economical to throw away, for example, 5¢ of product instead, by not having it.
However this analysis assumes that the 25¢ is passed onto the consumer. If the consumer is very price-sensitive (for example there is a standard price and very standard volume, as is the case with milk, though that isn't dispensed this way) then adding this as a competitive advantage would benefit the consumer, while the supplier eats the costs as a cost of acquiring this consumer.
This is my quick analysis.
The weighted end will tend to go towards where the liquids are. Imagine a bottle being held lengthwise. The weighted end will be in the same location as where the liquid is.
Turn the bottle upside down... the weighted end drops to where the top of the bottle is, along with where the water is.
Standard pressure thingies still work - you still get a spray. No need for custom membranse.
I'm not sure you could actually make it work upside-down without crimping, but at any normal usage angle it works great.
For the example above, is the goal to be able to spray upside down? To ensure that the sprayer is able to spray a higher percentage of what's in the bottle? How large is that percentage improvement (90% up to 95%?), what's the incremental cost of increasing that percentage, and what is the actual worth of 5% of the contents of the bottle?
A draw tube that is flexible enough to fold in half, strong enough to not kink, sturdy enough to not collapse when bursts of suction are applied, weighted enough to stay in liquid, strong enough to assemble quickly and easily, etc. is probably also expensive enough to just not be an economical solution.
By the way, if you don't purchase cleaning supplies regularly you may have missed that a lot of those tubes have gone away - they're now molded as part of the bottle so just tipping the bottle will put all remaining liquid at the intake point.
Metal could interact with and damage a lot of different things.
From my perspective, having a great idea is not enough. Even having a proof of concept is not enough. There's a lot more that goes into building a successful business. Investors have to price in the chances of all the things that can go wrong in the process against the perceived value of the product.
Likewise, as a founder, you often need at least some investors that can help propel you forward in some way. That can be worth a lot more than dumb money.
I haven't watched the episode you mention, but generally this is how I think about it.
Which is the infuriating part, when the "investors" contribute nothing to the project but a tiny slice of money they didn't work for to begin with, and get vastly disproportional returns for it.
There are a limited number of good opportunities to invest in, so it's not like investors get to unilaterally set the terms of these deals. They have to compete with each other, at least on the most attractive deals. A savvy founder turns down money on bad terms.
If we wanna keep it in terms of a capitalist market, the problem is that investors are essentially selling a service just like anyone else, but because wealth inequality is where it is, there's relatively little competition in that "market". Thus, what you get is very high "prices" for relatively poor "service". This is a problem.
In an ideal free market, investors are just another kind of business, and would compete both on price and their offering such that everyone was getting a good deal and everything moved along efficiently. In the real world, investment is a very concentrated market, meaning that the deals are shoddy and inefficient.
I also think some people go on the show knowing that they're not going to get investment at a sensible equity level, and are really on there as a way of marketing their idea to a wider audience.
[1] http://www.dailymail.co.uk/sciencetech/article-4335468/Briti...
I knew I did when reading this thread until I saw this comment.
http://www.dailymail.co.uk/sciencetech/article-4335468/Briti...
Just pull the hose out and bend/twist it really hard in a specific direction. If it's not utterly stiff, winding it tightly around a pencil (or your finger, or just twisting the hose to that tight of a bend radius) is ideal. Hopefully this much flexing means that after naturally uncurling the curl will still "stick" to a useful degree for longer than a single usage.
One non-obvious extra detail: if the product is in a non-transparent spray bottle, before replacing the lid, rotate the spray pump so it faces the direction you've bent/curled the hose. Now a) you know which direction the hose is pointing and can eliminate "where is it in the bottle", and b) you just have to face it forward for it to work, which is intuitive.
[0] https://www.lesswrong.com/posts/W9rJv26sxs4g2B9bL/transcript...
This is a terrible example because its essentially a trick question. The illustration would highly depend on context.
Say you meet someone on the street and you casually ask them this question, or you ask this on a birthday. "Works" with regards to a refrigerator refers to "knowing how to operate", or perhaps the basics.
Whereas if its for the TV quiz program "engineering of the kitchen" or "an applicant for technician repairing Samsung's refrigerators", yes then its clear that more depth is meant.
That's not to say the Dunning-Kruger effect doesn't apply here. Its just that there's a level set for a debate due to the context which then presets also the level of the expected answer.
https://en.wikipedia.org/wiki/The_Chemical_History_of_a_Cand...
(you can also buy the lectures in book form on Amazon.)
Having watched the first lecture, I was thoroughly impressed by the design and presentation of this historical artifact, with (judiciously chosen) modern embellishments.
[0] https://www.popularmechanics.com/science/a25581/science-behi...
What’s great about that problem is that it isn’t obvious that there even is a problem in the first place. “How do trains stay on tracks? Well... they have wheels, don’t they?”
Then when the problem is explained, it sounds impossible. The solution you first think of is probably wrong.
Imagine writing software for a hydraulic computer!
The analog of the fluid in that analogy is electric charge/current, not electrons which move in the other direction (which kinda breaks the analogy as a result).
I'd bet in a poll of the general public, most people think electrons fly around a circuit like water in a pipe, which is of course completely wrong. I guess it's debatable whether the inaccuracy matters or not. But in general, I prefer analogies that are simplifications and leave out details, rather than those that are completely ass backwards from reality.
If people transfer their incorrect understanding of water to incorrect knowledge of electricity, that doesn't make the analogy bad.
Ultimately though, this concept was the breaking point for my EE class; It's when half the class dropped out to other majors. Not that I blame the analogy entirely for this, I think in general this is the point at which a lot of people lose connection with deeper sciences. It's the point where analogies to the physical world (matter) break down because we're now fundamentally talking about energy, which doesn't obey the rules all humans are accustom to. The world where we can't see it or relate it to our daily experiences but only talk about it through mathematics.
Sadly he is better know for a diagram he drew of an observation, the Phillips curve.
I fear that much like this hydraulic model, Steve Keen's work is likely to be ignored or ridiculed by future economists while they fret over religious X diagrams.
Largely out of the economic mainstream, since the 20th century, sadly.
At the same time, I almost feel like I shouldn't read the last book for a while, it's going to be really bittersweet.
https://bankunderground.co.uk/2015/06/30/banks-are-not-inter...
Do an image search for an automatic transmission valve body. It even looks like a big industrial circuit board. Some components are passive like a check valve, some are active like a valve which is operated by pressure from some other part of the circuit. Newer ones also have partial electronic control, with microcontroller-driven solenoids and actuators moving around valves to control hydraulic rams which finally engage or disengage clutches. But it all began with no electronics at all. Pretty neat trick if you ask me.
I remember being a kid taking apart my first Ford transaxle and being amazed by the sheer complexity, almost to the point where it seems biological. My dad bought a really bad one for a couple bucks at a junkyard. We didn't need it to fix anything, he just wanted to feed my curiosity. It was a great parenting move. I recommend doing it yourself if you find a cheap busted one, just to get the ideas flowing.
Almost all electric components can be replicated in pneumatics; capacitors, resistors, transistors, diodes (including Zener diodes)... And from that you can form simple logics.
One design we had to generate was to build a pneumatic gate which would open and close by pressing four buttons (two for each side of the gate) and light up a red, yellow or green light depending on whether or not the gate is moving (of course the lights use a pressure sensor).
Of course nobody builds that because such a system would be expensive compared to a Attiny with a shift register and a few relays capable of doing the same.
http://www.mdpi.com/2073-4441/7/9/5031/pdf (see page 13-14)
Edit: grammar
So let me try. Let's start with the piston pump on the left. The brown piece moves up or down in a tube, and the two black "T" figures are valves that open or close in response to water pressure.
The down arrow next to the piston indicates that the piston is currently moving down and pushing on the water. This causes the valve at the bottom to close and the valve on the left to open. So water comes out at the top left.
After the piston is pushed down as far as it will go, you start pulling the piston back up. This is not shown in the diagram, but now everything is reversed. The valve at the left closes, and the valve at the bottom opens, both in response to the pressure change.
So now, water is pulled up from the well or other source, filling the chamber. When it is full, you start pushing down again, and the cycle begins anew: the valve on the left opens and the valve on the bottom closes, pushing water out of the spout at the top left.
Once that makes sense, take a look at the plunger pump on the right side of the diagram. You will see that it works on exactly the same principle: when you move the brown part up or down, it pulls or pushes on the water in the same way as the piston pump. The only difference is in the shape of the moving part.
A little meta, but in these situations I usually try to improve the source and post a reply saying I edited it, instead of explaining it to one (or a few) person(s) here. Not saying it was bad that you just wrote a big comment explaining it completely! Just an idea of equal effort while reaching more people :)
According to the plunger pump page, there is another practical difference - the pressure seal on the plunger pump is "stationary" allowing for higher pressure. Not sure why being stationary relative to the housing (but not relative to the plunger) makes the difference there.
Edit: (reservoir = bottle)
Because it is small you can cause the bottle to collapse if you do a lot of spraying quickly, an effect you might have noticed before.
The streets are not aligned, are they?
Here's a streetview with Bennett Alley on the right and the bus tunnel on the left if you want to get a feel for the turn:
https://www.google.com/maps/@42.3731803,-71.1223078,3a,75y,1...
Unfortunately you can't see through to the tunnel from the other side of Bennett [0], but the good news is you can see the 3 buses in action!
https://www.google.com/maps/@42.3725618,-71.1225705,3a,85.4y...
Another trick for spraypaint bottles is to stomp them vertically if you run out of spraypaint, it won't hurt the system that takes your cap, and gives you little bit more paint.
A low speeds (laminar flow), Rayleigh's analysis shows that a simple liquid jet breaks up due to surface tension effects.
https://en.wikipedia.org/wiki/Plateau%E2%80%93Rayleigh_insta...
At higher speeds (e.g., transitional or turbulent flows), the mechanisms change. For your typical spray bottle (without a swirl chamber) I'd say turbulence is the primary cause of breakup. Aerodynamic influence won't factor in at typical air densities and cavitation isn't happening as it probably would break the nozzle.
Here's a conference paper I wrote on turbulent breakup theory, which hopefully is readable for anyone with an understanding of probability theory and basic turbulence theory: https://engrxiv.org/35u7g/
(RMS velocity is just the standard deviation of the velocity. Turbulent kinetic energy is an energy formed from the RMS velocity. Kolmogorov's 5/3 theory is used a bit, but you can just view it as power law distribution. Etc.)
I also have some small spray bottles with swirl chambers, which makes the bulk fluid spin, destabilizing the interface, leading to droplet formation. The spray angle for these is large compared against the simple pressure atomizer described previously.
One of the reasons I freaking love HN. No matter the topic, there are actual experts reading it and willing to comment.
The more common term is just "cylinder".
My understanding is that staging means 'standing place', and that the theatrical stage is just 'something to stand on'. You sometimes get scaffolding called staging in the UK.
The military use has the same root but is not derived from the theatre I beleive. A staging area is somewhere you stand and wait. Very similar in use to the staging-posts that a stage-coach goes through.
The meaning in git could mean directly this, somewhere to wait, or it could be derived from the further development of the process stages. The stage having become the journey itself rather than the stopping-point. Something is staged because you have completed a stage and are waiting to start the next stage. That is rather circular really.
At this stage I will pass you over to an article https://en.wiktionary.org/wiki/stage
I'm guessing the authors first language isn't English, but saying 'why' would be better suited to explaining why a spray bottle works for a certain solution or process.
Why does a spray bottle work well for watering a plant?
A spray bottle produces many small drops of water which is an effective method of covering the leaves of a plant.
I chose "Why" for reasons similar to what jstanley wrote. When I was first considering the mechanism, connecting these components by simple tubes seemed like it wouldn't work. Why then did it work?
Why does a spray bottle work [when it seems like it shouldn't]?
vs.
Why does a spray bottle work [well for watering a plant]?
I saw that sctb temporarily changed the title to "How", but it looks like we're back at "Why". I apologize if any readers were expecting a more metaphysical discussion about spray bottles, but I'd be more than happy to explore that in a future post!