Do you understand the difference between diameters De, DN, D, d, and Φ?
The pipes are seen every day, and the diameter of the pipes is often recited, but Dn, De, D, d, and Φ should be put together... For example:
DN200, De200, D200, d200, Φ200
Confused? Please tell me if you are a scumbag.
Generally speaking, the diameter of the pipe can be divided into outer diameter (De), inner diameter (D), and nominal diameter (DN). Let's tell everyone the difference between these "DDDD... "
DN refers to the nominal diameter of the pipe
Note: This is neither the outer diameter nor the inner diameter, it is the average of the outer diameter and the inner diameter, called the average inner diameter.
When the design uses the nominal diameter DN to represent the pipe diameter, there should be a comparison table between the nominal diameter DN and the corresponding product specifications.
Pipe materials such as gas transmission steel pipes (galvanized steel pipes or non-galvanized steel pipes), cast iron pipes, steel-plastic composite pipes and polyvinyl chloride (PVC) pipes should be marked with the nominal diameter "DN" (eg DN15、DN20)
De mainly refers to the outer diameter of the pipe
Generally, those marked with De shall be marked in the form of outer diameter ×wall thickness;
Mainly used to describe: seamless steel pipes, plastic pipes such as PVC, and other pipes that require a clear wall thickness.
Taking galvanized welded steel pipe as an example, the two marking methods of DN and De are as follows:
DN20 De25×2.5mm
DN25 De32×3mm
DN32 De40×4mm
DN40 De50×4mm
We are accustomed to using DN to mark welded steel pipes, and rarely use De to mark pipes when wall thickness is not involved; but marking plastic pipes is another matter; it is still related to industry habits, in the actual construction process The 20, 25, 32 and other pipes that we simply call all refer to De, not DN. There is a difference here. It is easy to cause losses in the process of procurement and construction if it is not clear.
The connection methods of the two pipeline materials are nothing more than screw connection and flange connection. Other connection methods are rarely used.
Both galvanized steel pipes and PPR pipes can be connected by the above two connections, but it is more convenient to use threads for pipes smaller than 50, and flanges for pipes larger than 50 are more reliable.
Note: If two metal pipes of different materials are connected, it is necessary to consider whether there will be a galvanic reaction, otherwise the corrosion rate of the active metal pipes will be accelerated. It is best to use flange connections, and use insulating materials such as rubber gaskets. All kinds of metals are separated, including bolts, which must be separated by gaskets to avoid contact.
D generally refers to the inner diameter of the pipe
d is the inner diameter of the concrete pipe
Φ represents the diameter of an ordinary circle
Φ can also represent the outer diameter of the pipe, but at this time it should be multiplied by the wall thickness.
Such as: Φ25×3, it means the pipe with the outer diameter of 25mm and the wall thickness of 3mm.
For seamless steel pipes or non-ferrous metal pipes, "outer diameter x wall thickness" should be marked.
Such as: Φ107×4, of which Φ can be omitted.
Some steel pipes in China, ISO and Japan are marked with wall thickness dimensions to indicate the steel pipe wall thickness series. For this type of steel pipe, the expression method is the outer diameter of the pipe × the wall thickness.
Such as: Φ60.5×3.8
The respective representation ranges of De, DN, d, and ф.
De-- PPR, PE pipe, polypropylene pipe outer diameter
DN--Nominal diameter of polyethylene (PVC) pipe, cast iron pipe, steel-plastic composite pipe, galvanized steel pipe
d -- Nominal diameter of concrete pipe
ф-- Seamless steel pipes or non-ferrous metal pipes should be marked with "outer diameter × wall thickness"
