normal liter

[Tarkus]

Hello everyone,
I press that the tire is not my field, but I have to dimensional the lubricant for a pneumatic motor and I have no idea what a normal liter is.
However the engine builder reports this data:
-air consumption = 560 nl/1'
lubrication oil = 3 grams / cubic meter of air passing by the engine. .
My engine works at 6 bar, so how much will the actual consumption of oil per minute be?
thank you in advance for the answer.

 

[volaff]

Bye.
I remember what is a normal cubic meter (but here we talk about gas): a cubic meter of gas at normal conditions i.e. at atmospheric pressure and temperature of 0à c.

I don't know if it can help you.

 

[meccanicamg]

normal liter is for compressed air of a litre at standard pressure and temperature. just googular to find the definition

 

[pagnotz]

if not mistaken, it is at atmospheric pressure (at sea level) as said, but at 20°c, not 0°c.

 

[MicheleDeBortoli]

Hi.

by normal liter means the amount of compressed air necessary or contained in a given tank, for example:

the volume of a tank is enunciated to the atmospheric pressure (1 bar approximately). in case you want to calculate the amount of air available at the pressure of 6 bar you just have to perform the following calculation:

(p+1)
where:
v= volume of pressure tank 1 (we assume 10lt)
p= pressure to which the air is compressed (we assume 6bar)
1= constant representing atmospheric pressure

10*(6+1)= 70nl

in your case the engine builder must also report the pressure to which his nl/min refer and you must verify that it is the same to which you work, now we do the reverse calculation, from normal liters we must find the liters (dm cubes) then:

560/(6+1)= 80lt (at atmospheric pressure)

inside the engine then pass 0.08 mc per minute then 3 grams every 12 minutes.

in case it is normal cubic meters instead, the amount of oil is the following: 3 grams every 2 minutes.

verify whether the manufacturer speaks of cubic meters or normal cubic meters!

I hope I didn't write nonsense and have been clear,

Good day

 

[meccanicamg]

Hi.

by normal liter means the amount of compressed air necessary or contained in a given tank, for example:

the volume of a tank is enunciated to the atmospheric pressure (1 bar approximately). in case you want to calculate the amount of air available at the pressure of 6 bar you just have to perform the following calculation:

(p+1)
where:
v= volume of pressure tank 1 (we assume 10lt)
p= pressure to which the air is compressed (we assume 6bar)
1= constant representing atmospheric pressure

10*(6+1)= 70nl

in your case the engine builder must also report the pressure to which his nl/min refer and you must verify that it is the same to which you work, now we do the reverse calculation, from normal liters we must find the liters (dm cubes) then:

560/(6+1)= 80lt (at atmospheric pressure)

inside the engine then pass 0.08 mc per minute then 3 grams every 12 minutes.

in case it is normal cubic meters instead, the amount of oil is the following: 3 grams every 2 minutes.

verify whether the manufacturer speaks of cubic meters or normal cubic meters!

I hope I didn't write nonsense and have been clear,

Good day

But if we're talking about normal liter of air... what's the oil?

 

[MicheleDeBortoli]

Of course I'm talking about lubricant oil

 

[meccanicamg]

I'm sorry. I had not read that there was also the insertion of oil... you know I had made a normal liter of wine when I had read.

 

[TECNOMODEL]

I take this post not being beneficial to this unit of measurement.
In a compressor I have, from a technical sheet, a flow rate of 252 m3/h, how many nl/min has flow rate?

 

[zeigs]

assuming that the compressor in question aspires to atmospheric pressure (typical of an air compressor), and to 0 °c, 4200 nl/min
in this case the volumetric flow of the compressor is numerically equivalent to that in mass (nl/min) so I only converted those that are already nm3/h in nl/min, i.e. 252*1000/60

 

[TECNOMODEL]

assuming that the compressor in question aspires to atmospheric pressure (typical of an air compressor), and to 0 °c, 4200 nl/min
in this case the volumetric flow of the compressor is numerically equivalent to that in mass (nl/min) so I only converted those that are already nm3/h in nl/min, i.e. 252*1000/60

I'm sorry, I forgot a fundamental fact: 252 m3/h are at 9.5 bar.
If I understood correctly, just divide the 4200 nl/min by 8.5, right?
so I get 494 nl/min.

 

[paulpaul]

Since the volume of a certain mass of gas varies according to p and t, it is necessary to specify the latter to define it. the "normal" conditions, for example, correspond to 1,01325 bar and 0 °c (273,15 k), and are often indicated by applying letter n to the volume measurement unit (nm3, ndm3, nl, etc.); Actually in the system is “n” is the symbol of newton, and it would be correct to write normal m3 or normal liter without anteposed symbols (even the liter is not unit yes, and you should use dm3).

the conversion of the volume from one condition to another is made by exploiting the equation of state (pv = mrzt), assuming coefficient of compressibility (z) constant and pairs to 1 – lawful in the common pneumatic applications, a little less in the applications with greater pressure, in which it is evaluated in other ways – and equalizing the mass in the two conditions: if the condition 1 is that of departure and the 2 “new”, the volume of the latter is

(b)(c)(c)(c)(c)(c))(c))(c)(c)(c)(c)(c)(c))(c)(c)(c)(c))(c)(c)(c)(c)(c)(c)(c)(c))(c)(c)(c)(c)(c)(c)(c)(c))(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(c)(

expressing the temperature in k (273,15 + t(°c)) and the pressure in absolute bars (1,01325 + p(s)); the expression obviously also applies to the courses.

therefore, if I have 252 m3/h reported to 9,5 bar (relative consumption) and to the temperature of 0 °c (I suppose, since it is not specified), I get first the normal m3 with the expression above:
(273,15/273,15) = 2615 m3/h normal

per minute, the flow rate becomes 2615/60 = 43,6 m3/min = 43600 dm3/min (liter/min).

There is nothing to do with flow conversions, the compressor suction conditions (unless we do not want to calculate the flow rate to the suction conditions of this, but was not required here).

N
also the bar is not a unit yes: but since 1 bar = 100,000 pa (the pa is unit si) and therefore, in the above fractions, the ratio of pressure expressed in bar and pa is equal, is lawful and more intuitive to use the bar in this case.

 

[exxon]

less bad that you put some rigor on this thread. in some previous posts there were things on which, more than a sheet, a quilt should be laid.. .

just to break the boxes, I add that even the dm3 is not part of the units (the prefix "deci" is not part of it). the only volume unit is the m3, and you can pass to the liter knowing that 1 m3 = 1000 l.

 

[paulpaul]

@exxonI don't know. Are you sure? It seems to me instead that it is a allowed prefix, as well as the centi, the milli, etc.https://www.nist.gov/pml/weights-and-measures/metric-si-prefixes

 

[exxon]

@exxonI don't know. Are you sure? It seems to me that it is a prefix allowed. . .

I thank you for the question because it made me go through things that I haven't been controlling for a long time.

In fact, the ten, cent and decade prefixes are listed among the possible in the system yes, but in the guide to the use of the unit system, issued by the same nist
https://physics.nist.gov/cuu/pdf/sp811.pdf7.9 choosing prefixes (choice of prefixes yes), read

it is often recommended that, for ease of understanding, prefix symbols should be chosen in such a way that numerical values are between 0.1 and 1000, and that only prefix symbols that represent the number 10 raised to a power that is a multiple of 3 should be used.

(It is often recommended that, by clarity, prefixes be chosen so that numerical values are between 0.1 and 1000, and that only prefixes are used that represent the value of 10 high to powers that are multiple than 3.)

This recommendation in fact excludes the ten, cent and decade prefixes, ec.
In fact, it is not an imposition, but a recommendation. . .

At the same time, it is recalled that the appropriate choice of prefixes depends also on the particular scientific field to which reference is made. In electronics, for example, the prefixes whose exponent is not multiple than 3 are in fact prohibited, with the exception of decibel (db). Also in mechanics, the use of the centimeter or the tenmeter are not recommended and in technical drawings it is mandatory the use of the millimeter.

These clarifications generate what takes the name of the engineering system or system of engineering units that are the standardization of what is mentioned in paragraph 7.9 of the above mentioned document.

in physics, however, all prefixes are used and the multipliers are expressed with multipliers having all the entire exponents and not only the multiple ones of 3. the same size is expressed by a physicist as
1.2 x 10 5 m
while an engineer like
12 x 10 )6 m (or 12 μm)

Nice discussion. . .

 

[paulpaul]

indeed the prefixes "deci", "centi", "deca" and "etto" in particular, although being part of the yes, are very little used if not in specific sectors.
I mentioned the dm3 as a unit equivalent to the liter, however tolerated as a submultiple of one unit si (as is tolerated the bar as multiple of another unit si).
I see instead employed relatively often the prefix "deca" to indicate a couple of clamping (danm), as almost numerically equal (approximating g to 10 m/s2) to the old kgm, thus saving the formality with the operativity, since often in the workshop is reasoned still per kgm (formerly "chili": with the bolon who goes to des kilos...in the jargon of my zones).
I am fixed with the measuring units, as their incorrect use ingenerates misunderstandings that, in addition to highlighting basic gaps, may have serious repercussions even from the contractual point of view (the reference conditions for a volumetric flow of a compressor are a typical example).

 

[exxon]

I am fixed with the units of measurement, as their incorrect use generates misunderstandings that, in addition to highlighting basic gaps, may have serious repercussions even from the contractual point of view. . .

I would hope a totalitarian rigour against those units of measure "of convenient" such as danm (≈ kgm), hpa (= mbar), å (= 0.1 nm), hp (≈ 735.5 w or ≈ 745.7 w) and others, which should simply disappear from the scientific world, as arms, leagues and mercan degrees have disappeared.

If enough rigor was adopted in schools, a generation would be enough to get rid of it. Unfortunately it is the same teaching body that drags forward this malcostume that makes learning more difficult and more difficult information exchange.

Perhaps they will disappear along with the "short ton", the "long ton", and all the imperial system. . .