What is more is the radius or diameter. How to determine the diameter of a pipe
(sphere , surfaces the ball) passing through centre this circle (sphere, sphere). Also the diameter is called the length of this segment. The diameter of the circle is chord , passing through its center; this chord has the longest length. The size of the diameter is two radii.
Diameter symbol
The symbol of the diameter "⌀" (may not be displayed in some browsers) is similar to the one with the lowercase crossed out with the letter "o" . AT Unicode it is under the decimal number 8960 or the hexadecimal number 2300 (can be entered in HTML code like ⌀ or ⌀). This symbol is not present in standard layouts , so to enter it with a computer set, you need to use ancillary tools - for example, the application " symbol table "In Windows, the program" symbol table "(Formerly gucharmap) in GNOME , the command "Insert" → "Symbol ..." in the programs Microsoft Office etc. Specialized programs can provide the user with their own ways of entering this symbol: for example, in CAD AutoCAD To enter the symbol of the diameter, use the combination of characters %% c (letter c - latin) or \\ U + 2205 in the text string.
In many cases, the diameter symbol may not be displayed, as it is rarely included in fonts - for example, it is present in Arial Unicode MS (shipped with Microsoft Office, when installed as "Universal font"), DejaVu (free), Code2000 (shareware) and some others.
Conjugated diameters of ellipse and hyperbola
Adjacent diameters of ellipse
A pair of conjugate diameters of an ellipse. If a straight line parallel to the conjugate diameter is drawn at the points of tangency of the diameter with an ellipse, then the line will be tangent to the ellipse and four such tangents tangent to all four ends of the pair of conjugate diameters of the ellipse form the parallelogram described near the ellipse
- The diameter An ellipse is called an arbitrary chord passing through its center. Conjugated the diameter of an ellipse is called a pair of its diameters, which have the following property: the middle of the chords parallel to the first diameter lie on the second diameter. In this case, the middle of the chords parallel to the second diameter lie on the first diameter.
The figure shows a pair of conjugate diameters (red and blue). If a straight line parallel to the conjugate diameter is drawn at the points of tangency of the diameter with an ellipse, then the line will be tangent to the ellipse, and four parallelograms (described in the figure) described near the ellipse form the four tangents tangent to all four ends of the pair of conjugate diameters of the ellipse.
Conjugated diameters of hyperbola
k ⋅ k 1 = ε 2 - 1 = b 2 a 2 (\\ displaystyle k \\ cdot k_ (1) = \\ varepsilon ^ (2) -1 = (\\ frac (b ^ (2)) (a ^ (2) )))- If the diameter of hyperbolas a b, then the diameter b divides the chords parallel to the diameter a. Such diameters are called mutually conjugate.
- The main diameters hyperbolas are called mutually conjugate and mutually perpendicular diameters. The hyperbola has only one pair of principal diameters-the real and imaginary axes.
- In the case of hyperbolas with asymptotes forming a right angle, its conjugate hyperbolas are obtained by its mirror reflection with respect to one of the asymptotes. With such a mirror reflection, its diameter will change to conjugated diameter, which is simply the diameter of the conjugate hyperbola (see Fig.). Also. as the perpendicularity of the conjugate diameters on the circle is observed (in the figure on the left), a similar orthogonality is observed for conjugated diameters Hyperbolas with mutually perpendicular asymptotes (in the figure on the right).
Quite often there is a situation where you need to make a small renovation at home. For example, replace the area of the water supply system, heating system, sewerage or gas supply pipes (which is very rarely done on its own, but still theoretically possible).
Or it is necessary to make a new water supply system, and for this it is necessary to accurately determine the diameter of old pipes in order to purchase new ones of the same diameter, but from a different material. Or even instruct the repair of masters, but first you need to purchase a pipe of the required diameter.
Of course, there are a lot of specialized measuring instruments available on the market that allow to make measurements quickly and accurately. For example, rulers-zirkometers or laser meters. But in the workshop of the home master, there are not always such specialized high-precision devices ready at hand. Therefore, the question arises: how to determine the diameter of the pipe by improvised means?
What are the diameters and what are they measured in?
Before proceeding to measurements, let us recall a little that the pipe diameter is not necessarily indicated in centimeters. Historically, it has become customary that often the pipe dimensions are indicated not in metric (and us familiar) centimeters, but in inches. The value of one inch is 2.54 cm.
In addition, it should be borne in mind that the pipe has two diameters - outer and inner. The internal diameter determines the capacity of the pipe (plumbing, sewer, and so on). But the outer diameter is more important for installation - it is on the outside of the pipe that the thread is applied and a threaded connection is determined on it.
Pipes of different materials have different wall thicknesses, which determines the difference between the outer and inner diameters.
Let's get down to business - we are looking for an instrument
There are several different ways to measure the diameter of a pipe. To increase the accuracy of the measurement, one must resort to one or another method to avoid mistakes. Most often, the conditions of choice depend on the availability of the pipe itself.
The most common and simple way to measure - using a caliper. But, firstly, the calipers are not in every household. And secondly, pipes of large diameter (sewer, for example) can not be easily measured with a small household meter. But the easiest method that does not require complex specialized tools can come to the rescue.
To calculate the diameter of the pipe, you will need:
- Flexible ruler, tailor's centimeter or roulette;
- Knowledge of the number Pi (3.14);
- Calculator.
Measure this way you can both a pipe, and any other object of circular cross section - a column, a bar, a garden bed and so on. It is necessary to perform only one measurement - to find out the length of the circle. To do this, wrap the pipe with a flexible ruler, centimeter or tape measure exactly along the circumference (if it is a flower bed - then in the widest part). Then divide the obtained value by 3, 14 (lovers of precision can divide by 3, 1415926) and get the pipe diameter in centimeters.
In order to translate the dimensions into frequently used inches (for water pipes), multiply the value by 0.398. Conversely, in order to translate the inches indicated in the specifications (especially on imported pipes) into centimeters, the diameter in inches must be multiplied by 2.54.
Pipes of small diameter - features of measurement
If you want to measure the diameter of a thin tube, you do not need to invent anything especially - the easiest way is to measure the diameter with an ordinary caliper. The only condition is providing access to the pipe. And, of course, the presence of the calipers. This method is suitable for measuring accessible pipes of not very large diameters (up to 150 mm).
The easiest way is to attach the caliper to the end of the pipe, press its legs against the outer walls and look at the value obtained. It will be the required diameter.
What if the pipe is not available?
If you can not get to the end of the pipe, (for example, it is part of the installed system), then its diameter can also be measured with a caliper. Just hold the compasses not to the butt, but to the side surface perpendicular to the pipe. In addition, the length of the legs of the measuring device must be greater than half the diameter of the pipe being measured.
The basic method of measurement remains the same as mentioned before. Using a tape measure or cord, the circumference is determined. And then, dividing the obtained length by 3.14, we obtain the required diameter.
For example, if the circumference is 31.4 cm, the pipe diameter is 314 mm: 3.14 = 100 mm.
Method of remote measurement by photo
This not quite standard method for determining the diameter is used when there is no measuring instrument available or it is impossible to get to the pipe with it. In this case, the question of how to determine the diameter of the pipe is solved using a mobile phone or a camera.
To do this, near the pipe, you have an object of all known sizes (most often a matchbox with a wall length of 50 mm, or a coin). And take pictures of the "installation" on your mobile phone. Then, directly on the photo (or on the computer screen), the dimensions of the pipe and the known object are measured. It remains only to translate all the digits into real size, using the rule of proportionality.
Determination of the internal diameter of the pipe
The easiest way to measure the internal diameter of the pipe is to cut it. For example, using a caliper, after measuring, the inner diameter at the maximum point. Sometimes the inner diameter is calculated by subtracting twice the wall thickness from the outer diameter.
Methods for controlling the parameters of pipes in production
In large-scale production, the outer diameter of thick pipes (for water supply or sewage) is also measured by a tape measure.
However, a more precise formula is used:
D = L: 3.14 - 2Δp - 0.2 mm.
The diameter (D) is determined taking into account the double thickness of the tape (Δp) and correction is made for the roulette to adhere to the pipe wall, which is 0.2 mm from the experimental data. Also taken into account is the magnitude of the permissible deviation. For example, for a pipe with a diameter of 200 mm, the deviation should be no more than 1.5 mm in any direction.
Most often, the permissible deviations are expressed as a percentage. For products with a diameter of 820 to 1020 mm, the deviation should not exceed 7%. To measure pipes of this diameter in industrial conditions, ultrasonic meters are used.
The thickness of the walls in the factory conditions is measured directly, using a caliper. In this case, the deviation of wall thickness from the nominal should not exceed 5% (especially in the direction of decreasing).
In addition, production parameters are subject to such parameters as curvature and ovality.
- Curvature (deviation from a straight line) should not be more than 1.5 mm per running meter, and the total curvature should not exceed 0.15% with respect to the total length.
- The ovality of the pipe (that is, the ratio to the nominal diameter of the difference between the largest and smallest diameters) should not be greater than 0.8% -1%. The largest and smallest diameter can be obtained by measuring the inner diameters in the two perpendicular planes with a holometer.
However, if you just need to measure the diameter of the pipe for replacement, then you need it in complex calculations and high-precision devices do not. Get the value of the diameter of the pipe can be, using improvised tools and knowledge from the school course of mathematics.
A straight line connecting two points of a circle (spheres, hyperspheres) and passing through its center || its length.
- ru (geometer)
- The value of the spherical triangle "Y" "is equal to the value of the triangle opposite to it" "ABC" ", in which the side" "AB" "is common with the triangle" "P" ", and the third angle" "C" "lies at the end point diameter sphere, going from "" C "" through the center of the sphere.
- On the right triangle's triangle, both on diameter a circle is constructed.
- The round pool has three sazhens diameter.
- On the back, everyone was sewn a black circle, two inches diameter.
- en (math.)
- Every "n" "- dimensional convex body diameter "" d "" can be split into "" n "" + 1 part smaller diameter.
Hyperonyms to the word diameter
- length
- line segment
- diameter
- distance
- chord
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