# Tag Info

18

Spray cans work by containing a propellant which has a boiling point a small amount below room temperature. When the can is sealed the liquid and vapour reach equilibrium at a relatively modest pressure. When the spray valve is opened this pressure forces out the contents as an aerosol and more of the propellant evaporates as the internal pressure drops. ...

10

is it possible to increase the heat output of the burner by connecting two low-pressure supplies in parallel via a T-piece like this one? The primary factor is gas pressure at the tee. If the gas pressure drop from the low pressure regulator to the tee is negligible and the first tank & low pressure regulator is able to supply enough gas to ...

9

No, connecting two tanks together will not double the flow. The regulators fitted to tanks limit the pressure and flow rate so all you do is double the amount of gas the burner has available ie doubles the time of use. Do NOT interfere with the regulators. There are automatic change over systems that have both tanks connected and it switches over when one ...

5

There are two aspects to this. First is that the main advantage of hydraulics is that is provides a compact means of greatly multiplying force but in compressing gasses you have to a huge amount of work on the gas itself so the constraint is the power input so you are always limited by the capacity of the motor driving the compressor. Consider that the ...

4

One advantage these chemical systems may have over compressed tanks is how well they are suited for intermittent use and long-term storage (as opposed to regular, continuous operation). The US FAA Aviation Maintenance Technician Handbook points out this advantage on page 16-5: Sodium chlorate chemical oxygen generators also have a long shelf life, ...

4

From personal experience of refuge systems, oxygen generating systems are preferred over medical oxygen gas tanks because of space requirements, portability and the ease of relocation. When emergency refuge systems are designed and installed, either underground, in mines or tunnelling projects or at industrial plants like oil refineries and chemical plants, ...

4

Structurally the pressure is independent from the nature of the gas. So, it shouldn't matter if its $N_2$ or $O_2$. Special care should be taken with corrosive gases, but usually that means the containers need to be manufactured with corrosion resistant materials. Regarding $H_2$ my main concern would be if it leaks out. Hydrogen is the lightest known gas. ...

3

Assume that high temperature causes no chemical reactions in the contents or between the contents and the can. High temperature will increase the pressure in the can. Assume the can is fully unaffected in its mechanical integrity up to the point that it fails. With all of the above, when you get the can back at room temperature, it will have no change in ...

3

According to to the SDS found here the product contains tetrafluoroethane as an ingredient. I looked around and found other similar products with the same ingredient. For sake of simplicity lets say that all the $400 ml$ are tetrafluoroethane and the compressed density is $1.01 g/cm^3$ according to your table. With this information we know that one can ...

3

How do I explain the fact that the flow chokes only at the nozzle? To explain why the flow only chokes at a single point, it is important to remember that for a system at steady state, there can only be a single flow. All of the fluid entering the system must leave. Since there can only be a single flow rate through the system, you must then consider ...

2

As a reality check lets consider industrial gas tanks as the specifications are easily available. A BOC size D hydrogen tank has a gross weight of 57kg and contains 23kg of hydrogen at 230bar. At atmospheric pressure hydrogen has a density of 0.09 kg per cubic metre so you get about 255 cubic metres of gas at atmospheric pressure. This will give lift ...

2

It sounds like you might be looking at a similar setup to purge gas for arc welding. Here you would typically a regulator which screws into the valve fitting of the gas bottle which provides coarse control for flow-rate and also has a pressure gauge so you can see how much gas is left in the bottle. For fine control applications like TIG welding it is ...

2

Sort of. Certainly things like pressure cookers and turbochargers use blow off vales as a routine way to regulate pressure. Generally this is to make sure that internal pressure doesn't exceed some design maximum rather than for fine control and it is a bit contextual as it tends to imply that whatever working fluid you are dealing with goes to 'waste'. ...

2

The elephant in the room is that while gasses are compressible, hydraulic oil is only negligibly so. This difference has two major effects: Firstly, the output volume flow is limited by the intake volumetric flow divided by the compression ratio. Let's say we have a hypothetical compressor that pulls in 10 L of air per second at STP, and raises the ...

2

Isolated System An isolated system allows no mass or heat flow. The equation for an ideal gas is $$p V = n R T$$ where $p$ is pressure, $V$ is volume, $n$ is number of moles, $R$ is the gas law constant, and $T$ is temperature. Use the molar mass $M$ and the relationship that density $\rho = m/V = n/MV$ to obtain your equation.  m = \frac{V}{MRT}\ p $... 2 Thanks for a nicely presented first question. First you need a model for the equation of state for the tank. Given the initial conditions, develop formulas that yield static pressure, temperature, work, etc as a function of the mass remaining in the tank. (You need at least one fully defined state point for the tank, I'm assuming it's the initial condition). ... 2 The turbine blades are what turns the compressor blades in the first place. They do this by extracting work from the hot gas shooting out of the combustors at high speed, and feeding it forward on a spinning shaft to the compressor blades. Those blades then suck air into the engine and force it into the combustors hard enough that the hot gas generated in ... 2 No. The regulator itself will see to that. It's around 30 millibars - 3/100 0f a Bar. The pressure inside a gas cylinder is around 10 Bars - 3,000 times that of what gets into your stove! It wouldn't matter if you had ten cylinders all feeding the regulator, it could still only deliver that 30 millibars to the stove. The only way to get more gas, therefore ... 2 Rolling diaphragms are nothing new. The shaft connected to the rolling diaphragm projects through the housing (unlike the image shows). You generally pressurize the fluid through the shaft. Creating a vacuum on the fluid can cause the membrane to invert; cycling through full stroke can reset the membrane. The image was captured from https://www.... 1 First get the newest edition of Perry's Chemical Engineers' Handbook a.k.a The Chemical Engineer's Bible which covers at the very least the basics of pretty much everything you need. Then look at Coulson & Richardson's Chemical Engineering series and pick up the volumes you need. Pretty much everyone has used at least Volume 6 (Design) now and then. ... 1 The best way to approach this question is through basic thermodynamics. Suppose you have a compressor and a turbine but no combustion in between. Then we can define processes in this machine as follows: 1 to 2: isentropic compression (for simplicity) 2 to 3: nothing 3 to 4: isentropic expansion (in turbine) I urge you to draw a P-V diagram at this ... 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 The mass flow across a turbocharger is constant: If X kilogrammes of air go in then X kilogrammes of air come out. However if the pressure is twice the inlet pressure then the output volume is smaller and the density is higher as well as the temperature is increased. This is one reason there are intercoolers as having too high an inlet temperature reduces ... 1 We assume isothermal as having to include all the heat gains and losses to the gas during the cycle would be too onerous and add little to the accuracy of the result. 1 Have a look at the following: https://industry.airliquide.us/volume-compressed-gas-cylinder Based on this, if you assume a gas cylinder of 47 litres (standard size) at 200 bar fill pressure, you have:$P_1 V_1 = P_2 V_2$where:$P_1$= 200 bar (above atmospheric pressure) = 201.325 bar (absolute pressure)$V_1$= 47$lP_2 = P_{atm}\$ = 1.01325 bar (...

1

By knowing the volume flow rate of a gas , you can also find the mass passing through a cross section area for certain thermodynamic conditions.

1

Id say a regulator is more optimised for attaining a given setpoint with precision and lack of chatter, whereas a relief valve is more concerned with reliability and less with finesse. But you are correct on an abstract level they are both flow control feedback mechanisms of a very similar kind; though in practice you are unlikely to confuse the two ...

1

According to one of many resources regarding pressure in propane tanks, a tank with 20 pounds of gas at 70°F has a pressure of 145 psi, at 90°F would have 180 psi, at 105°F would have 235 psi, and at 130°F would have 315 psi. Those numbers convert to 21°C / 10 bar, 32.2°C / 12.4 bar, 40.5°C / 16.2 bar and 54.4° / 21.7 bar respectively. Quite substantial ...

1

The units of "liters of Argon / CO2 per minute" is a flow rate (volume delivered in time) and is not equivalent to "pressure of compressed air in Bar" which is pressure (force / area). Would you get what you need if you connected a pressure gauge to the output side?

1

Are you sure your numbers are right? 3 atm of pressure drop is pretty large for 10 m length with that diameter. Anyways what you need to do is 1) Guess a velocity, gas pipes are usually about 20 m/s but for flare headers it can go up about 90% of speed of sound. So the range is quite large. 2) Calculate Reynolds number and find friction factor from a ...

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