Before the PVC plug-in pipes are mounted together, the gasket slots are cleaned with a cloth, and the gasket is inserted into the clean gasket slot, and the top of the gasket and the pipe's non-plugged part are wetted with arab soap or glycerin as much as the muff's length and are joined to each other by hand.
Pipe stacking should be done properly. (Figure A)
In order for PVC pipes to serve their purpose for many years, pipe trench floors must be properly leveled. On floors other than earthen floors, the pipe should be made ground safe with the bottom fine sand layer, and the sides and top of the pipes should be covered with a fine sand layer, and they should be protected from external impacts.
Pipe trench excavation; It should be of sufficient depth, taking into account the frost level. (Figure B)
Pipe elbows and fittings should be supported with supporting concrete (Figure C)
Press the pipes in the trench. Before the tests, it is necessary to cover the pipes with soft soil or fine sand material (provided that the pipe collar remains open so that it can be seen). (Figure D) Pipes can be used for water transmission up to +45 °C. (Figure E)
Nominal Pressure - Wall Thickness Formula
The ratio of pipe outer diameter to wall thickness is called SDR:
SDR=Outer Pipe DiameterWall Thickness
The one half of the SDR is called the pipe series (S):
As an example, the SDR value of a pipe with a 63 mm outer diameter and 3 mm wall thickness is 21, and the pipe series is 10.
MRS (minimum required strength) value, on the other hand, is the value calculated by regression analysis of the minimum strength of the raw material in the design life of 20°C, 50 years, according to the ISO 9080 test. This value is accepted as at least 25 MPa according to TS EN ISO 1452-2 standard for PVC raw material class.
Design stress, σs, on the other hand, is obtained by dividing the raw material MRS value by a service (design) coefficient C and this coefficient is for PVC pipes TS EN ISO 1452 In the -2 standard, it is accepted as 2.5 for diameters up to 90 mm (including 90 mm), 2.0 for 110 mm and larger diameters:
Finally, the nominal pressure is found by the following equation according to the wall thickness of the pipe and the MRS value of the raw material:
PN=10σsS=< /em>20σsSDR-1=20 MRSC(SDR-1)
For example, the nominal pressure of a 63 mm outer diameter, 3 mm wall thickness PVC pipe is 20 . 252,5 633- 1=10 ;becomes a bar.
The volume of the fluid passing through the section of the pipe in one second is called the flow rate. Its unit is m3/sec and is calculated as follows:
Flow Calculation in Free Water Flow (Hazen–Williams equation)
In one pipe, 4 – The flow rate of free-flowing water at 25°C is calculated according to the Hazen-Williams equation as follows:
v=k x C x rh0.63 x < em>S0.54
For PVC pipes, the roughness coefficient, C, is considered equal to 150. Hydraulic semi-diameter, r, is the fluid passing through the pipe; It is the ratio of the area of the cross section to its perimeter and is calculated as follows:
rh=πR-2e2 22πR-2e2= R-2e4
If the line slope is S, the pipe's end is; pointIt is equal to the ratio of the height difference between the pipes to the pipe length. "For example, the beginning of a 12-meter pipe; If there is a difference in height of 3 meters between the end points and the end points, the line slope is equal to S 3/12=0.25.
The flow rate in the free water flow is the flow rate formula; Q=vA and Hazen–Williams equation can be combined as follows:
Q=vA=k C R-2e40.63 S0.54 πR-2e22=kπ41.63< /em> C R-2e2.63 S< /em>0.54
The constant kπ41.63 in this equation can be taken as approximately 0.2784. From another point of view, the line slope required to generate a given flow rate can be calculated as follows: