Design_Chengdu Chengtai company official website

DELICATE DESIGN

The problems such as the pressure-drop increased, flow insufficient, condensation water being fail to be discharged, difficult maintenance and repair are mainly caused by unsuitable design of piping or insufficient pipe diameter and too fast flow speed and cause the pressure drop to increase due to the factory expansion.To alleviate the drawbacks of the single line piping, if the site space allows, the loop line piping shall be adopted as much as possible. When the compressed air consumption suddenly increases in this way, the compressed air can be fast supplied from two directions to the minimum degree pressure-drop. So, this piping type is suitable for obtaining the relatively stable supply of compressed air (stable pressure and airflow). The installation position of the air compressor will expand piping type into: a loop piping with single supply terminal, or a loop piping with multi supply terminals.

We must design the main pipe as a loop network to ensure the compressed air consumption and pressure balance.

PIECEWISE CONTROL DESIGN

Moreover, Isolation valves shall be allocated on all kinds loop piping according to different functional areas, so that the pipeline can be separated by them into sections without influencing the air supply for other areas, the repair and maintenance can be carried out.Multi-valve is convenient for piecewise control

Low water system design

When designing and laying the pipe, the main pipe must form a slight incline to ensure that the condensation water in compressed air pipe can be discharged smoothly; the angle is about 1~2%. Draining devices shall be installed at the lowest point of each main pipe.

AIR/WATER SEPARATION DESIGN

The main pipe and branch pipe are connected via crooked swan neck pipe to prevent the fluid water or oil in the main pipe from flowing into the supply terminal of compressed air which will affect the service life of the equipment and tools.The swan neck pipe can prevent the fluid water or oil from flowing into the supply terminal of compressed air.

SELECTION THE PIPE DIAMETER ACCORDING TO THE FLOW RATE

The pipe diameter is determined by the maximum flow demand and the length of the main pipe. It is crucial to control the pressure-drop around 5% relative to inlet.For a pipe loop, the length to be used is the maximum distance between the compressed air source and the outlet.

Air compressor kw	Flow rate m3/min	CT stainless steel pipe length & diameter
Air compressor kw	Flow rate m3/min	50m	100m	200m	300m	500m	800m	1200m	2000m
1.5 — 7.5	0.5	20	20	20	25	25	25	32	32
1.5 — 7.5	1.0	20	20	25	25	25	32	32	40
11 — 22	1.4	20	25	25	25	32	32	40	40
	2.4	25	25	32	32	32	40	40	50
	3.2	32	32	32	32	40	40	50	50
30 — 55	4.4	32	32	40	40	40	50	50	80
	6.5	40	40	40	50	50	50	80	80
	9.0	50	50	50	50	50	80	80	80
75 — 110	11.6	50	50	50	50	80	80	80	100
	15.0	80	80	80	80	80	80	100	100
	17.8	80	80	80	80	80	100	100	100
132 — 185	21.0	80	80	80	80	100	100	100
	24.6	80	100	100	100	100	100	100
	28.0	100	100	100	100	100	100

The pipe diameter mentioned above is nominal diameter, such as DN20mm.

EXPANSION WITH TEMPERATURE

Although the coefficient of thermal expansion of the stainless steel pipe is much lower than that of aluminum pipe, plastic pipe and other pipes, the temperature variation throughout the year may still cause the extension and contraction of longdistance pipes.

Expansion coefficient of CT stainless steel pipe: 0.016 mm per metre and per℃.

The rubber sealed joint of the CT stainless steel piping itself has ability to make up this little expansion, which depends on the number of the joint. But, we must take the compensation of thermal expansion into account for overlong straight pipe while designing the pipe network.Example: a 20-metre line of DN32mm pipe installed at an ambient temperature of 15°C and subjected to a maximum temperature of 40°C. Overall expansion: 0.016 x 20 (m) x 25 (40°C - 15°C) = 8 mm

The pipe or the barrier will be damaged if the expansion or contraction is blocked, hence, the leakage, even accident, will occur.

DESIGNED AS LOOP PIPE NETWORK

The main pipe shall be designed as loop network. If there is multistory building, each layer shall be in plane circulation and vertical circulation shall be formed between each layer.

PIPE SUPPORT INTERVAL

The pipe support shall be specially designed according to the requirements regarding the layout and the laying of pipe network in different environments. The basic principle is to plan the pipe support uniformly according to factors such as support intervals of different pipes, safe clearance between the pipe and barrier, load of the support and beauty of the pipeline routes.

Support interval (at 25℃)

CT stainless steel pipe	DN20	DN32	DN40	DN50	DN80
Support interval	2m	3m	3m	4m	4m

The supporter to be located as close as possible to the joint (max.20cm). Typically, no more than 1 pipe joint shall be set in 1 support interval.

FONTER PVR COMPRESSED AIR PIPING DESIGN

SELECTION THE PIPE DIAMETER ACCORDING TO THE FLOW RATE

The pipe diameter is determined by the maximum flow demand and the length of the main pipe. It is crucial to control the pressure-drop around 5% relative to inlet.The table below can be used to determine the tube diameter depending on the network length and flow rate to be distributed.For a pipe loop, the length to be used is the maximum distance between the compressed air source and the outlet.

The main pipe should be large enough to cater for future extensions and avoid pressure-drops.

Air compressor kw	Flow rate m3/min	PVR pipe length & diameter
Air compressor kw	Flow rate m3/min	50m	100m	200m	300m	500m	800m	1200m
1.5 — 7.5	0.5	20	20	20	40	40	40	40
1.5 — 7.5	1.0	20	40	40	40	40	40	40
11 — 22	1.4	40	40	40	40	40	40	40
	2.4	40	40	40	40	40	40	63
	3.2	40	40	40	40	40	63	63
30 — 75	4.4	40	40	40	63	63	63	63
	6.8	63	63	63	63	63	63	63
	9.0	63	63	63	63	63	-	-
	11.6	63	63	63	63	-	-	-

The pipe diameter mentioned above is outer diameter, such as Ø20mm.

EXPANSION WITH TEMPERATURE

To compensate for expansion or contraction phenomena due to temperature variations, the PVR network must be fitted with absorption mechanisms. These mechanisms must be supported on brackets. The network expands when the operating temperature rises and contracts when it falls.

Expansion coefficient of PVR pipe: 0.06 mm per metre and per °C.

Example: a 20-metre line of Ø40mm pipe installed at an ambient temperature of 15°C and subjected to a maximum temperature of 40°C.Overall expansion: 0.06 x 20 (m) x 25 (40°C - 15°C) = 30 mm We must take the compensation of thermal expansion into account for overlong straight pipe while designing the pipe network.