Axial Expansion Joints for Piping

Axial compensators and bellows expansion joints

Axial expansion joints absorb movement along the pipeline axis caused by thermal expansion and installation tolerances. Selection depends on nominal diameter, design pressure and temperature, required movement, cycle life, media, materials, end connections and the applicable piping code.

Published configuration data

The tables below are reference data for the configurations shown. Final selection must be confirmed for the actual operating and test conditions. For high-pressure service, provide the complete design case so a suitable construction can be checked rather than selected only by nominal diameter.

Operating temperature: up to 450˚С

Working pressure: up to 16 bar

Number of cycles: not less than 1000

General characteristics

Almost all types of compensators are manufactured with fittings for welding, except for rubber compensators. The material for manufacturing the connecting branch pipe of the compensator for welding can be, depending on the type of device: stainless steel, galvanized steel, steel grade 20, as well as alloy steel grades required by the customer. Axial compensator type KSO is designed to compensate for thermal expansion on straight sections of pipelines, as well as inaccuracies in their installation.

Axial compensators are characterized by

- Nominal internal bore diameter;

- the value of the working target stroke (angular degrees, millimeters);

- permissible maximum pressure (bars, atmospheres, pascals);

- operating temperature, taken into account in the calculations of the working stroke values;

- material (ordinary structural steel, stainless steel, alloy steel) and type of connecting fittings (flanged, threaded, welded);

Nominal diameter DN, mm	Nominal diameter DN, mm	30 mm (±15)	45 mm (±22.5)	60 mm (±30)	d, mm	s, mm	h, mm	Impact area, cm2	Nominal pressure PN bar
25	1″	180	-	-	33.7	2.6	50	18	16
32	1 ¼″	180	-	-	42.4	3.2	50	18	16
40	1 ½″	190	220	-	48.3	3.2	50	22	16
50	2″	185	215	-	60.3	3.6	50	36	16
65	2 ½″	185	215	240	76.1	3.6	50	58	16
80	3″	185	215	245	88.9	4.0	50	78	16
100	4″	200	230	265	114.3	4.5	60	124	16
125	5″	200	230	265	139.7	5.0	60	180	16
150	6″	245	270	315	165	5.0	80	252	16
200	8″	265	305	340	219.1	4.5	80	430	16
250	10″	310	360	395	273	5.6	100	660	16
300	12″	310	360	395	323.9	5.6	100	910	10
350	14″	320	370	405	355.6	6.3	100	1060	10
400	16″	320	360	400	406.4	7.1	100	1420	10
450	18″	330	375	420	457	8.0	100	1750	10
500	20″	340	385	430	508	8.0	100	2180	10
600	24″	320	360	390	610	8.0	100	3110	6
700	28″	340	385	425	711	8.0	100	4250	6
800	32″	320	340	380	813	8.0	100	5510	6
900	36″	335	360	405	914	8.0	100	6900	6
1000	40″	315	305	350	1016	8.0	100	8580	6

Nominal diameter DN, mm	Nominal diameter DN, mm	30 mm (+10/-20)	60 mm (+20/-40)	d, mm	Impact area, cm2	Nominal pressure PN bar
25	1″	210	-	38	16	16
32	1 ¼″	215	-	42.4	18	16
40	1 ½″	220	-	48.3	23	16
50	2″	210	-	60.3	37	16
65	2 ½″	210	295	76.1	58	16
80	3″	210	290	88.9	79	16
100	4″	215	300	114.3	128	16
125	5″	220	310	139.7	183	16
150	6″	240	325	168.3	268	16
200	8″	240	345	219.1	437	16
250	10″	240	335	273	705	16
300	12″	250	340	323.9	984	16

Operating conditions of axial bellows expansion joints KSO

First of all, the performance characteristics must be determined by the target tasks that the axial bellows compensator must perform. During operation, it must:

- withstand the maximum operating pressure, as well as the test pressure to which the pipeline is subjected;

- do not reduce the pipeline capacity;

- easy to install and repair;

- do not reduce the values of target parameters below the permissible limit under the influence of mechanical vibrations and temperatures.

All characteristics of axial compensators are given for a temperature of 20 ⁰ C, as well as for a thousand complete compression-extension cycles.

- working environment pressure: not higher than 125 kg/cm2.

- working environment: steam, water, oil products, gases, etc.

- operating temperature range: -260 +800 C°.

The required value of the working stroke is achieved by the number of bellows corrugations.

Axial flange compensator (with blind/floating flange)

The axial flange expansion joint with a floating flange greatly simplifies installation, since the flanges can be easily and freely rotated to ideally fit the bolts to the holes, as well as when replacing equipment. The axial flange expansion joint with a blind flange allows a more rigid connection to be achieved by welding to the bellows.

Axial compensator for seasoning type KSO

- type of execution: with protective casing and internal screen;

- number of sections: two or one-section (one, two bellows);

- bellows material: stainless steel grades 12X18N10T, 08X18N10T;

- screen, casing: steel St. 20 or stainless steel 12X18N10T, 08X18N10T;

- welding branch pipe and flange: stainless steel 12X18N10T, 08X18N10T or steel St. 20;

- nominal diameter: 15 - 10,000 mm;

- connection type: welded, threaded, flanged.

Information required for a quote

Send the DN or NPS size, design and operating pressure, design and operating temperature, media, required axial movement, required cycle life, bellows and pipe materials, connection type, installation length, quantity and applicable code or customer specification.

Related expansion-joint pages

See the expansion-joint overview, bellows expansion joints and fabric expansion joints.

Request a U.S. quote

Evek LLC serves customers throughout the United States. Typical delivery is 2–3 weeks, subject to design review, specification and availability.

Contact Evek LLC with the complete operating data and delivery ZIP code.