Product Made in Japan
Manufacturer: NFK
Model: NK-7900, NK-7900E

NFK expansion joints are used in gas and liquid transport system lines used by steel making, chemical and industrial plants to transport substances such as air, water, gases, steam, oil and exhaust gases. They can compensate for expansion and contraction caused by temperature differences in air-conditioning/sanitation lines in buildings and other structures. They also handle conditions such as line center misalignment, vibrations, foundation subsidence and earthquakes.

NK-7900

 

 

Materials

 

① Bellows	Stainless Steel
② Flange	Carbon steel, Stainless Steel

*You can add Internal Sleeve and Shipping Bolt as options if you need.

 

Bellows for NK-7900E E Bellows

 

DN	Thickness(mm)	ID(mm)	Convolution Height(mm)	Pitch(mm)	Expansion / contraction amount per Convolution(mm)	Resisting pressure(N/mm)
20	0.2	28.6	4.7	4.0	0.60	373.3
25	0.2	35.6	5.5	4.0	0.75	310.3
32	0.2	44.1	6.7	5.0	1.10	209.1
40	0.2	50.1	6.9	5.0	1.15	217.8
50	0.2	62.1	7.4	5.0	1.25	222.6
65	0.2	78.4	9.0	6.5	1.85	150.3
80	0.3	90.9	10.0	6.5	1.55	450.4
100	0.3	116.2	10.0	7.5	1.65	524.3
125	0.3	141.9	10.0	7.5	1.65	630.6
150	0.3	167.4	11.0	7.5	1.90	583.3
200	0.3	218.7	11.0	7.5	1.90	750.5
250	0.3	270.4	13.0	10.0	2.70	527.8
300	0.3	319.9	13.0	10.0	2.70	619.8
350	0.4	356.0	15.0	13.0	2.70	1268.0

Bellows for NK-7900 iO Bellows

DN	Bellows Size(mm)				Production possible Convolution	Resisting pressure(N/mm)	Expansion / contraction amount per Convolution(mm)	Effective cross section(㎟)
	Thickness	Convolution Height	Pitch	ID
20	0.3	4.7	6.0	27.0	32	1352.8	0.45	819.4
25	0.3	5.5	6.3	33.5	32	1092.6	0.55	1228.5
32	0.3	6.7	7.0	42.0	32	787.9	0.75	1908.9
40	0.35	6.9	7.5	47.5	32	1255.1	0.75	2384.5
50	0.35	7.4	8.5	59.5	32	1214.4	0.90	3589.1
65	0.4	9.6	9.5	75.0	25	1130.0	1.20	5728.0
80	0.4	10.6	10.5	88.0	25	976.6	1.40	7760.0
100	0.4	10.6	10.5	113.0	25	888.5	1.60	12449.2
125	0.5	11.0	12.0	138.0	38	4941.2	1.40	17671.5
150	0.5	13.0	15.0	164.0	30	3450.5	1.80	24884.6
200	0.5	13.0	15.0	216.0	30	2216.8	1.80	41547.6
250	0.5	16.0	18.0	268.0	25	1492.2	2.70	63794.0
300	0.5	18.0	20.0	317.0	22	1243.2	3.50	88668.3
350	0.6	18.0	20.0	356.0	22	2398.9	3.00	110564.5
400	0.6	23.0	25.0	406.0	17	1333.0	4.70	145355.2
450	0.6	23.0	25.0	456.0	17	2983.2	4.70	181106.6
500	0.6	23.0	25.0	507.0	14	1645.9	5.90	225978.7
550	0.8	32.0	35.0	558.0	12	1803.9	7.80	270992.8
600	0.8	32.0	35.0	609.0	12	1747.0	7.80	320092.6
650	0.8	32.0	35.0	660.0	12	1885.6	7.80	377622.2
700	0.8	32.0	35.0	710.0	12	2021.6	7.00	434278.8
750	0.8	32.0	35.0	762.0	12	2162.9	7.00	497140.8
800	0.8	36.0	40.0	812.0	9	1609.5	8.70	566916.2
850	0.8	36.0	40.0	864.0	9	1708.0	8.70	638436.5
900	0.8	36.0	40.0	914.0	9	1802.7	8.70	711211.5
1000	0.8	40.0	45.0	1015.0	8	1450.2	10.50	876821.3
1100	0.8	40.0	45.0	1117.6	8	1590.9	10.50	1055374.6
1200	0.8	40.0	45.0	1219.2	8	1730.4	10.50	1248482.0
1350	0.8	40.0	45.0	1371.6	8	1939.6	10.50	1568545.6
1500	0.8	40.0	45.0	1524.0	8	2148.7	10.50	1925092.1