How much cfm psi in a can of propellant?

I want to sandblast/etch an image onto acrylic. so i was wondering how close do the specs of canned air get to an actual sandblaster. Ive searched and couldnt find this anywhere. How much cfm and psi is there in a can of propellant. Can anyone help me with this?

Posted by bsmith102 5 years ago | last reply 5 years ago


Question Regarding Measurement of Vacuum Pump Air Flow Using Anemometer

Hello everyone, I am new to Instructables and am loving it so far. I was reading through some literature on a piece of equipment we have at work and it requires 18"Hg @ 25CFM. We have flow gauges at work, so it is just a matter of using one to determine the flow but it got me thinking... What is the most effective method of measuring airflow of a vacuum pump without a flow gauge. All I have is an anemometer, a basic understanding of physics and time. So I came up with this method and am looking for some folks to poke holes in it: I placed the anemometer at the end of a 36" piece of PVC with a 1.6" I.D. sealing the anemometer to the PVC to ensure no air gets pulled around the fan of the anemometer. The other end of the pipe is reduced to a 1/4" line (.16" I.D.) which is connected to the vacuum pump. Turning on the vacuum pump yields a steady 3.5MPH (307.98 ft/m)on the anemometer. Doing the math, I come up with 4.3CFM (307.98ft/m*.013962634ft^2).  Unfortunately, I cannot bring a gauge home from work to compare and I cannot bring my set up, as glorious as it may be. So this is more a thinking exercise. So what sort of accuracy would you guys think this 'rig' has? Can you think of some method for me to verify it's accuracy (or, more likely, lack thereof)?

Posted by mmcdonald6 8 years ago | last reply 8 years ago


I'm looking for a high volume, small size air compressor but I can't find a good one. What do you guys recommend? Answered

I need an air compressor that has an EXTREMELY high CFM (Cubic Feet per Minute) rating. It is for an air-powered exoskeleton (crazy idea, I know). It needs to be pretty small, backpack sized if possible, It doesn't need that big of an air chamber (fire-extinguisher sized). Continuous run is a must. Powering it shouldn't be a problem because I will be carrying ~ 30 pounds of Li-ion batteries for running the compressor. I also won't be needing more then ~ 100PSI. Weight is an almost non issue, I wouldn't mind a 20 pound compressor, I'll probably remove the frame anyway, so that will take away some weight.

Asked by bowmaster 8 years ago | last reply 8 years ago


What does osi stand for? Answered

As in, "a 16 osi blower delivers 400 cfm of air through a piping system..." I know that cfm is a way of writing cubic feet per minute. PSI is pounds per square inch. Building systems to move gases and liquids around safely has really had me stumped till now, especially when dealing with HVAC. I'm not familiar with some of these units.

Asked by Vorenus 7 years ago | last reply 7 years ago


What will multiple vacuum pumps do to a vacuum system, namely to PSI?

Long story short, I'm looking to make a vacuum forming table, and have most of the thing designed. However, I am looking to use two (maybe three) cheap vacuum pumps until I have the money to get a decent vacuum pump. I know that the pumps (4 CFM) if stuck in parallel will get me roughly 8 CFM, however, what will that do to the PSI? The pumps have a 90 PSI pull (if thats the right phasing to it) and I'm unsure what grade of pip/tubing to get for this. Thanks in advance!! 

Asked by DoctorWoo 5 years ago | last reply 5 years ago


How do I go about making a Lutron 120vac 60hz household dimmer light switch capable to use for 12vdc??

I want to use this switch for examle in my car connect by the accessory or cigarette lighter plug and it will run a 12vdc fan motor i can control cfm/speed.

Asked by KrAx 7 years ago | last reply 7 years ago


need help with converting an rc signal to rs 485 nwbe help plz?

I have a project involving converting a rc signal to a signal the max1318 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4222/t/al can understand. I know that i would need to use a pic micro controller but idk how to use one or which one to use. Could I please be directed in what purchase to make?

Asked by hurtzmyhead 9 years ago


looking for multi- speed quiet wall mount range hood 900cfm for a home

1. any one know where I can get a good reliable easy to clean multi-speed(min 6) range hood with max throughput 900 cfm? prefer    - under $900 with good warranty. most of the time use only 100 to 200cfm    - price include any custom, brokerage, if needed to Alberta Canada 2. baffle or other filter  (I'm new to kitchrn hood, want something easy to clean, low maintenance, low operating cost)

Asked by gg89 3 years ago | last reply 3 years ago


Anyone use a Car air filter for home use?

Hello all~! An Idea just flew in my mind! Has anyone used or thought of using a Car air filter for home use? my primitive plan says a Car filter (My car's looks like a tunnel/Chimney) with a high CFM computer Fan mounted on top. The fan would be driven on 12v Adapter (or 9v for silence and life) and would suck air through the filter. The dust would then stick to the outside surfaces of the filter, which can be brushed off / Vacumed later. Any Pros/ Cons/ Ideas? Jump in! People!

Posted by bhvm 6 years ago | last reply 3 years ago


What do I need to make laptop stand cooler?

I would like to make my own custom laptop stand cooler with fan (6 fan) of 8 or 9cm The reason why I need it that many is because my laptop gets overheat quickly & sometimes it shuts down by itself. Ps: I would like to connect the fans to wallplug with adapter or usb wall plug adapter. 1. I would like to know what do I need besides 6 fan, mdf / acrilyc for the stand, adapter, usb cable? 2. For this project, which fan is the best for me, 2 pins, 3 pins or 4 pins? 3. Moreover, which voltage should I have a look and which 1 is better: high rpm or cfm flow? Thanks Edit 1: Sorry as Im complitely blind with electricity, I will have to ask lots of questions. Hp already acknowledge the problem but cannot do anything with the overheating other than suggesting using external fan & at this moment im using deskfan to blow the exhaust hole of the laptop. So this is for example the fan that I found on eBay Voltage, 12V. Voltage range, 6 to 13.8V. Current, 0.20Amps. Speed, 4500RPM at rated voltage and zero pressure. Flow (max), 67CFM. Pressure Rise (Max), 0.3inH2O. Thanks again for all the answer Edit 2: To make it easy, this is my question 1. Id like to put 5 fans with above spec, does that mean I need power adaptor that can handle 1A (5x0.20A) ? 2. Would it be better if I use power adaptor 2000mA or better to stick with 1000mA ? 3. Im planning to use dc connector head (see pict) but I only see 2 cable holes. If the fan has 3 or 4 cables, which cable should be put in the minus hole and which one in the plus hole, and what to do with the rest of the cable(s) ? 4. Would this power adaptor perfect for my project? Sorry again with this dummy questions, but like I said Im complitely blind with electricity. Thanks for all the answer

Asked by rronald_25 6 years ago | last reply 6 years ago


Technology Makes Cheap Drinking Water from Air

INTRODUCTION:   How can we best apply basic technology to help the underprivileged and/or disaster-hit countries like Haiti? Daily hygiene and nourishment are among the top needs for disaster ridden regions!  Simply put, no water means no hygiene. The Romans understood that over two millennia ago and created their complexly beautiful aqueduct networks for handling both fresh and wastewater! Other ingenious water systems like “air wells” have been found in the city of Theodosia (cf: discovered in 1900 by Zibold, see Zibold’s Collectors/Dehumidifiers) dating back to Greco-Roman times during the Byzantine Empire. These were strictly passive systems that naturally dehumidified air, collecting its potable water in underground basins. All air, even in relatively dry desert regions, will precipitate or release its natural water content (initially in the form of vapor) through condensation when it hits its dew-point temperature and below. That means you “chill” it to an appropriate level that is anywhere from 5F to 50F below its current air temperature, depending upon how much water content (relative humidity) it has locally absorbed. The condensation of the water vapor releases its internal latent heat (reheating the cooled air) which must be constantly dissipated (absorbed by something) in order for water formation to steadily continue. So how do we dissipate this resultant vapor-heat and chill our air without any infrastructure or electricity, in an underprivileged or disaster-ridden region? We simply bury a long cast-iron or any metallic drain-pipe sufficiently underground where the temperature of the earth is naturally held to a constant at around 45F to 55F. That’s our “free” chiller gift from nature. One end of the pipe, Figure-1,  sticks out of the ground to suck-in local outside hot air, and the other end dumps cooled dry air and water into an underground cistern where it gets collected and is piped to the surface to both exhaust the cooled dry air and connect to a water pump. We need a hand operated water pump to lift up the water above ground, and we need an electric fan to constantly pump air through the ground-chilled piping system. We can even force the cooled piped air to exhaust into a tent-like structure where it provides air conditioning as an added bonus, but this adds the penalty of both power and the increased fan size necessary to drive our required airflow further into an enclosure! While this concept is not “passive” (requiring electricity to work) like those clever Byzantine air-wells, it will produce much more potable water and within a smaller volume than those elegantly passive historic devices. The electricity for our fan power requirements can be produced by any one of four ways using either “active” or “passive” techniques: 1) An active playground or bike-pedaling-person or oxen-driven mechanism-generator, 2) A passive windmill generator, 3) A passive solar energy collection system that directly generates electricity, or 4) A passive thermo-electric system that directly generates electricity using the Peltier effect, operating solely on temperature differences between the cell’s top and bottom surface (we jury-rig the cool pipe and hot ambient air to contact separate sides of the cell). Depending upon how much water is needed, the required air volume plus pipe length and diameter, together with the fan will be sized accordingly. We can also configure groups of parallel fan-driven air pipes that are radially fed into the cistern. The sizing of this underground network depends upon the ambient air’s local average temperature and relative humidity (how much water gets absorbed into the air) plus buried pipe depth and effective underground temperatures achieved. The basic concept is one where we “wring” water from air at some given humidity content. The higher its relative humidity the more water is recovered from the air. The air-wringing process simply chills the air as it scrubs along the cooled internal pipe surface until it starts to rain inside the pipe from condensation onto its surface. The condensation is like the dew that forms on car windows, grass or any cooled surface in the early morning, before the sun comes out and evaporates the dew back into the heating air. A further bonus is that our dew-formed water is naturally distilled and very clean. It is potable water ready to drink without the need for additional sterilizing agents. Of course, we must make sure that the interior piping and cistern network is biologically cleansed before burying it underground. The hand pump with its 10 to 15 foot extended piping to reach the underground cistern must also be cleansed. The beauty of this constantly replenishable water supply is its convenient underground installation anywhere! After the in-ground installation, we have a virtual, partially passive, no moving parts, non-breakdown system containing above ground total access to all moving parts that could breakdown, namely the water pump and electric fan. Also, it is easily maintained, with few moving parts (water hand-pump and electric fan) and basically lacking any technical complexity which makes it ideal for technologically backward regions. The example below uses a relatively small industrial fan moving air at 1500 CFM (Cubic Feet per Minute) with a DC motor rated at 1kW. This fan together with our underground piping system will conservatively generate 12 GPH (Gallons Per Hour) of potable drinking water without need for any purification chemistry. Based on an average electrical cost of 14-cents per kWh (kilo-Watt hour), the typical commercial distillation of one gallon of drinking water costs roughly 35-cents as compared to our cost of only 1.2-cents. Furthermore, if we decide to go green and use solar energy for generating our water, it would effectively cost us nothing beyond the initial installation! USING A PSYCHROMETRIC CHART TO SIZE OUR WATER SUPPLY: The following gets a little technical and is only provided for those die-hards who are truly interested in how the science works. Those non-technically schooled may skip this part and not miss the basic concept. Figure-2 shows a Psychrometric Chart for air. This chart summarizes some of the basic thermodynamic properties of air throughout its typical range of operating temperature. The chart uses six basic air properties that defines the physical chemistry of water evaporation into air:  (1) the enthalpy or total energy contained within a unit of air which is a combination of its internal and external energy, expressed as the amount of BTU-energy per unit mass of reference dry-air, (2) the specific volume or the ratio of a unit volume of local air to its mass of reference dry-air, (3) the humidity ratio or the amount (mass) of moisture in a local unit of air divided by its reference mass of dry-air, (4) the percent relative humidity per unit of local air, or the mass ratio (expressed in percentage form) of the partial pressure of water vapor in the air-water mixture to the saturated vapor pressure of water at those conditions (the relative humidity depends not only on air temperature but also on the pressure of the system of interest),  (5) the dry-bulb temperature or the locally measured air temperature, and (6) the wet-bulb temperature or saturation temperature which is the local air temperature experienced during constant water evaporation (a wet-bulb thermometer is typically used:   a thermometer that measures resultant temperature while wrapped in a water wet-gauze and spun to generate local air movement and max-evaporation)  1.0   The Process and A Sample Calculation Our Psychrometric Chart uses six thermodynamic properties that help to determine the amount of water available for extraction from the local ambient air as a function of its temperature, pressure and relative humidity.  Let’s assume the following local ambient conditions for the region we plan to construct our water system at:  (1) Typical daily air temperature Td = 106F and one atmosphere pressure assumed at sea-level, (2) Relative Humidity, RH = 55%, and (3) Typical underground temperature down at six feet is measured at Tu=55F (at 12ft. it drops to ~45F). This yields the following calculated results for obtaining a steady-state supply (changes at night) of water to fill the cistern:      1)      In our example, the “local” air (dry-bulb) temperature is Td=106F, at a relative humidity of RH= 55%.  Fig-2 indicates that the resultant Humidity Ratio is HR= 0.0253 Lbs-water/Lb-Dry-Air (intersection of Td=106F line and RH=55% line, then horizontal to HR value).  We then determine the “gulp” of air volume containing the HR Lbs-water which corresponds to the point of intersection of Td and RH. Interpolating on specific volume “mv” yields mv=14.7 ft3/Lb-Dry-Air (this value sets the optimum unit airflow for our given ambient conditions, and creates a ballpark pipe length to diameter ratio needed later). It represents the basic unit of air volume that will enter our underground pipe per given time, and ultimately defines the size of our fan and piping network. For increased water creation, multiples of this unit volume will scale up the additional amounts of water that can be collected. 2)      As the inlet air cools down to a temperature of Tu=55F, from contact with the relatively cold underground pipe, we follow the constant enthalpy line (red upward left-diagonal) from the intersection of Td and RH to its saturated air temperature condition of Ts= ~88F, which is its dew-point temperature where the corresponding local RH=100%.  At this temperature or under, the air precipitates and releases its moisture content, resulting in water condensation onto the pipe walls.  Since our air will chill to a final pipe temperature of Tu=~55F, we follow the RH=100% saturated curve (green) down to yield an HR=~0.009 Lbs-water/Lb-Dry-Air. This is how much water is left in the air when it gets to 55F.  Therefore for every pound of local outside air that enters the pipe, mw=0.0253 – 0.009 = 0.0163 pounds of absolute pure, distilled potable water precipitates onto the inside pipe wall (per pound of dry air that is cooled and dehydrated) to gravity-flow out the pipe exit and into the cistern. 3)      We now convert pounds of air per unit time into a unitized volumetric airflow that yields gallons of hygienically pure potable water production per unit time. For every Va=100 ft3 of local volumetric air movement per minute (CFM) through the pipe, which translates into ma=Va/mv= 100/14.7 = 6.8 lbs. of dry air per minute or 6.8 * 60 = 408 lbs. per hour (PPH), to yield a water-flow of mwf=ma * mw = 408 * 0.0163 = 6.65 PPH or 6.65/8.345 = 0.8 GPH of water.  An industrial fan rated at 1kW DC will typically move 1500 CFM at a pressure of 8-iwc, to continuously produce 15 * 0.8 = 12 GPH of pristine potable water. 4)      Not shown here are the design details of sizing our pipe, fan and solar collection system for electric power requirements using heat transfer principles coupled with a thermodynamic heat balance, and aerodynamic fan performance assessment. These details help to size the electric power generation requirements plus margin used to properly size a solar collector containing further margins for overcast days. The engineering involved here is straight forward but beyond the scope of the current project.

Posted by RT-101 6 years ago | last reply 8 months ago