This is a rough copy of the Dannenbaum LLC Hyspan Vibrasnub Catalog. Please contact Dannenbaum LLC for the original copy.

Advantages: Hyspan Barco Ball Type Flexible Strut Joints

Double Acting—Handles both tensile and compressive loads. Accommodates push, pull and slide movement with positive control.

Precision Built—Factory machined to close tolerances and rigidly inspected. Reduces the possibility of dangerous errors in field construction.

Lower Cost—Lower initial cost compared to other motion control and restraint methods, and economical operation. Maintenance Free permanently lubricated. No adjusting or service required.

Simplifies structural designing and eliminates the need for special struts, tie-rods, or clevis-and-pin arrangements which are not as flexible, and are subject to stress and binding.

Safety—High load carrying capacity for reliable service in severe conditions, combined with easy calculation of proper sizes to promote safety in structural design.

Hyspan Barco Ball Type Flexible Strut Joints function as positive restraints in process systems where the restraint is required in one direction, yet some movement must be allowed in other directions. This is accomplished by using a flexible ball type joint located at each end of a solid strut.

Hyspan Barco Ball Type Flexible Strut Joints may be applied for static or dynamic loads. They are equally rated for tensile or compressive loads. The most common uses are:.

  1. Structural sway bracing for hot stacks and pipes;
  2. Supports or hangers for horizontal piping;
  3. Stability supports far tall or slender towers, structures or vessels;
  4. Restraints to direct and control thermal expansion away from components that should not be stressed, such as turbine nozzles and pump.

Hyspan Barco Ball Type Flexible Strut Joints have been used for years by many leading engineering and construction firms. Compared to other restraint methods like sliding plate guides, A-frames or clevis-and-pin arrangements Ball Type Flexible Strut Joints are simple to apply, economical to erect and less cumbersome.

Dannenbaum LLC has better Charts in the Hyspan Vibrasnub Catalog.


Inches 3/4 1 11/2 2 3 5 6 10
mm (20) (25) (40) (50) (80) (125) (150) (250)
Loading: Lbs. 7,000 10,000 14,500 20,000 40,000 80,000 120,000 250,000
(kN) (31.2) (44.5) (64.5) (89) (178) (356} (534) (1112)

Dannenbaum LLC Hyspan Vibrasnub Catalog.

Table 3 Dimensional Data



Part No.



In. (mm)






















Shipping Wt:. Lbs. (kg)

BB-35500-16 3/4×1 (20X25) 3.50










1.DS (26,7) .179






BB-35500-20 1×1-1/4 (25X32) 4.25
















BB-35500-32 1-1/2×2 (40×50) 5.75








1.90 (4B,3) .218






BB-35500-40 2×2-1/2 (5DX65) 6.00




5.00 (127,D) .218










BB—3550D—64 3×4 (80×100) 6.62




6.ID (165,1) .300












BB-35000-66 5×6 (125×150) 7.50








10 63


3/4’”-10 12







(168, )



BB-35000-68 6×8 (15Ox200) 8.88










7/8″-9 12








225 0


BB-35000-72 10×12 (25Ox300) 14.38


B.25 (209,6) 22.D0 (558,8) .843




1-1/4’”-7 20










For fabricates assemblies complete with extension pipe, contact Hyspan.

How to Order

1. Determine tensile or compression load for your application. Select the ball end size to handle this load from.

Design and Engineering

Hyspan Barco Ball Type Flexible Strut Joints can be installed in any position from vertical to horizontal. The joints at either end can be attached to a pipe, vessel or flat plate steel structure by butt-welding. Flexible  strut joints should be located at a distance from any hot mass or surface to maintain their operating temperature below a maximum of s50″F (343°C).

The total load to which the joints will be subjected will determine the selection of the proper size. The total load includes: 1) normal operating load(s); 2) sudden or wind-shock loads; 3)the forces or loads involved in decreasing the distance between the supporting and sup- ported structures when one or the other structure must move, like periodic thermal expansion and contraction. The distance decrease is a result of the supported pipe or structure moving axially. That causes the ball strut joint attached to it to describe an arc about the ball strut joint attached at the anchor point (see illustration above). This change in distance causes a positive deflection in the moving structure — it must be considered in design.

These deflections can be minimized by: 1) make the rigid strut between the joints as long as possible, consistent with good structural practice and considering the accept- able L/R ratio; 2) install the strut arrangement in the cold position so that this deflection takes place only during heat-up or cool down.

For additional engineering assistance, please contact Hyspan.

Shipping Notes each Ball Type Strut Joint is shipped separately-two are needed for each flexible strut. The center connecting pipe, weld reducers (if needed) and studs for ends are to be furnished by the customer.



Please visit us for the original Dannenbaum LLC Hyspan Vibrasnub Catalog it has the figure pictures.


Fig.1 — This illustrates a typical use for Vibrasnub Hydraulic Snubbers in a two-plane assembly on a large U-bend in a modern refinery. The snubbers allow slow expansion movements lo occur but dampen out shock and vibratory movements.

Fig.2 — This drawing illustrates the use of one pair of Flexible Strut Joints to provide lateral stability to an other- wise unstable, narrow elevator structure. Although the structure is over 200 feet (61.2m) high, overturning movement due to wind load was greatly reduced. This resulted in a savings in both the design of the foundation and in the structure. Flexible Strut Joints also provide a positive compression or tension member which flexes to accommodate the thermal expansion of the sup- porting vessel.

Fig.3 — Two Ball Type Flexible Struts in “A” frame arrangement allow vertical expansion of the stack or process line. They also prevent excessive horizontal movements due to wind forces and give stability to the line. Large over headline Flexible SIM Joints.

Fig.4 — Two Flexible Struts allow thermal expansion movements of the vessel and line without restraint and pro- vide rigid support of the large overhead line. They are used in place of noisy and cumbersome sliding plate guides and structural brackets.

Fig .5 — Vibrasnub Hydraulic Snubbers allow vertical expansion of the hot vessel and provide a tight mechanical connect ion to transmit high-frequency vibrations to the snubbers.

Fig.6 — A high -temperature header can be restrained completely with zero axial movement by using Strut Joints at a point relatively distant from the resisting structure. This is important where the branch piping is not flexible enough to absorb extraneous movement from the header without overstressing the equipment to which it is attached.

Fig.7 — This is a supporting arrangement for boiler water wall down comer pipes in a large steam generating station. Two Flexible Strut Joints are used as compression members. They eliminate the need for overhead hanger steel which would cantilever beyond the column. Conical action of the strut joints accommodates lateral and axial movement of piping.

Fig.8 — Engineers needed to brace a 60ft (18.3m) high power plant boiler against wind sway and allow for downward thermal expansion of the boiler and its integral furnace. The boiler is supported  by hanging from  the top within four I -beam corner columns. Eight Flexible Struts, in opposite pairs.

Fig.9 — Spring support and restraint for a 30″ (750mm) exhaust pipe from a high-pressure turbine. Two Flexible Strut Joints permit vertical expansion movement of the exhaust pipe, but pre- vent any horizontal movement of the vertical section of pipe.

Fig.10 — A single Flexible Strut Joint is used as a compression member that eliminates weight-moment at the barometric condenser nozzle, thus permit- ting the nozzle to be the only support required for the condenser and barometric leg.

Fig. 11 — Builders of electric power plants use Flexible Strut Joints as guides to stabilize 200ft. (61.2m) high, steel smoke stacks. This economical and efficient structural design maintains axial alignment and resists wind sway while accommodating thermal expansion and contraction. Additional beams and columns were eliminated by the use of Barco Flexible Strut Joints.

Fig.12 — A single Flexible Strut pro- vides frictionless support far a large air blower intake pipe. Negligible forces are transmitted back  to the blower due la free expansion movement. The use at 35ft (10.7m) and 50ft (15.3m) were used to meet these requirements efficiently and economically. The use of eight struts allowed the construction of a lighter steel structure at the anchor points.

Fig.13 — Two Flexible Struts form a guide to stabilize a high, overhead vapor line. The struts allow vertical line expansion and reduce forces due to wind, shock loads and earthquakes.


Dannenbaum LLC Hyspan Vibrasnub Catalog will explain better. Hyspan Barco Vibrasnub Hydraulic Vibration Snubbers function as a stop or restraint for dynamic vibration and shock loads. These rapid movements may (or may not) be accompanied by slower natural movements, like thermal expansion or contraction. Rapid vibration movements are absorbed by the snubber assembly. More gradual thermal movement is accommodated by bypassing hydraulic fluid through a restricted orifice in the piston of the snubber cylinder. The Ball Type Flexible Strut Joints on each end of the assembly permit a +/-10° alignment movement to eliminate binding. Increased angulation available some sizes.

The Vibrasnub snubber is designed to be used to control dynamic vibration and shock loads. For continuously applied static loads, use Hyspan Barco Ball Type Flexible Strut Joints (see pages 3 through 4). See Dannenbaum LLC Hyspan Vibrasnub Catalog for pages.


Lower cost — Simplicity and long life, with minimal maintenance compared to other types of vibration and shock control mechanisms.

Reliable, long service life — Proven superior through years pf testing and installed use.

Fast, positive action — Resist and dampen shock and vibration loads instantaneously.

Eliminates binding — Permit +/-10° angular and conical movement of supported structure while dampening vibrations and shock loads.

Handles slower, thermal and seismic movements.

Engineering Data

How to Install Vibrasnsub Snubbers.

The Vibrasnub assembly can be installed in any position from horizontal to vertical. They should be used in pairs with an acute (less than 90°) interior angle. If only one snubber is installed, is must be installed directly in line with the trust force and the moving member must be guided to eliminate any possible lateral movement.

The Strut Joints at the end of each Vibrasnub assembly can be welded to pipe or steel structure. The anchor paints should be designed to withstand the total loadings and minimize secondary vibrations.

The Vibrasnub cylinder should be isolated from heat (or hot member of structure) with the pipe extension toward the heat source to prevent cylinder temperature from exceeding +150°F (•66°C).

Available Option

Piston Rod Only a nominal pressure drop created across the bypass orifice against slower thermal movements.

Stainless Steel

Clamps (2)

Protective Boot

Simplifies design and installation — Compared to other more complicated motion control systems.

NOTE: The reaction of Vibrasnub snubbers to total applied loads with respect to travel and vibration are shown in the graphs on page 11. Any applications which laid outside of the range of this data should be referred to Hyspan.

Neoprene boot is to protect exposed piston rod area against damage from dust, weather and corrosive atmosphere.


Cylinder: bored, honed, polished chrome plated bore. Pistons: furnished with metal piston rings, O-rings and a fluid bypass orifice. Piston rods: double-ended, ground, polished, hard chrome plated. Cylinder heads: 1/4” (8mm) standard pipe tap ports for filling with fluid; internal bleed duct for air elimination; fitted with gland packing nuts. Hydraulic Fluid: high-grade, petroleum-base fluid similar to U.S. Govt. Spec. MIL-H-6083 for -20 F (-29^C to +200OF (93DC). Strut Joints: joints permit +/- 10^ angular or conical movement. Ends beveled for buttwelding joints are described on page 3. One joint is tapped for piston rod; other joint has half pipe coupling for connection to pipe extension and is non-rotating to keep cylinder parts an top. Shipment: all component parts (except extension pipe)* snipped in one (1) container, cylinder filled with fluid.

For fabricated assemblies complete with extension pipe, inquire Hyspan. Contact us for Dannenbaum LLC Hyspan Vibrasnub Catalog,


Table 4 Specifications

Vibrasnub Size: In.










Nominal Pipe Size of Extension











Maximum Load:












Frictional Resistance:




7f (.0Z)







P>hipping Weight:













Table 5 Dimensional Data. For more accurate please contact us fro Dannenbaum LLC Hyspan Vibrasnub Catalog.


Size: Part Travel A B C D E F G G H J K overall dimension with full load
In(mm) Number In(mm) Min. Max Min.•      Max.-
1-1/2 BB-35001-24 t/-d 3.Z5 1.66 4.25 1.00 2.50 22.50 6.00 96.00 9.00 2.00 2.00 41.+5 131.75
(40) +/•(101.6) (82.6) (42.2) (108.0) t25.4} (63.5} (571.5) (152 4} (2438.4) (228.6) (CO) (50} (1060) (3346)
2-1/2 BB-35001-40 +/-6 4.25 2.JB 5.76 1.13 3.00 28.00 8.06 112.06 10.69 2.50 2.50 52.51 156.51
(65,0) +/-(154,4} (10B,0) (60,5) (146,3) (28,7) (76,2) (711,2) (204,7} (2.846,3) {271,5) (65) (65} (1.333,8) (3975,4)
4.0 BB-35001-64 +/-6 5,00 Z.88 6,00 1.50 +.75 29.19 6.75 181.25 11.63 4.00 ^.00 53.56 228.06
(100,0) +/-(152,4} (127,0j {73,2) (152,*) (38,1) (120,7) (74t ,4} (171,5) (4603,8) (295,4) (1g0) (100) (1360,4) (5792,7)

“1 1/2” size travel is • 4″. 2 1/2″, 4“ sizes travel is x 6“. Increased stroke available on special request.

The maximum overall dimension given above (C+F+G+H) can be increased, but only with a decrease in the allowable load in keeping with the increased L/R of the unit as a column under possible vibration.



Designing for Vibrasnub Snubbers

Situation: A hot stack is found to vibrate excessively and is also subject to considerable thermal movement.

Problem: Eliminate excessive vibration of hot stack and provide for thermal movement during heat up and cool-down.

Solution: Predetermined Facts:

Total vibration load     8000 lbs. (35,6kN)

Piston travel due to thermal movements  5 inches (127mm)

Heat-up and cool-down time   20 minutes

Frequency of vibration      60 cycles/min.

Total allowable vibration movement at point of snubber attachment without damage to stack 125 inches (3.2mm)

From the specifications table, it is seen that one 2*/2“ (65mm) Vibrasnub with a maximum allowable load of 12,00Dlbs (53.4kN) is sufficient. However, two are recommended Jar better installation (see Typical Installations).

In this example, the required rate of piston travel is 5“ (12Tmm) in 20 minutes or */4″ (6.4mm) per minute. Graph #1 shows that the resistance to movement is less than 20OIbs (.9kN) for each unit (the point of intersection with the slanting rate line is off the graph) and is negligible.

Graph #2 shows that the total vibration movement permitted by a 21/2″ (65mm) Vibrasnub snubber (using 2 units, each with 4000Ibs (17.8kN) load at 60 cycles/min.) is approximately .08″ (2.03mm). That movement is well below the stated allowable movement of .125″ (3.2mm). If the frequency of vibration had been 30 cycles/min. the total allowable movement would then be approximately .1B” (4.6mm) which is greater than that allowed far a 21/2“ (65mm) u nit. A 4” ( 100mm) Vibrasnub would be required.

Situation #2: A hot process vessel is developing excessive vibration in a large pipe that leads horizontally out of the vessel and then is directed upwards.

Problem: Eliminate excessive vibration in the pipe and provide for differential thermal movement of the pipe and vessel.

Solution: Predetermined facts:

Total vibration load                                                40,000 lbs. (178kN)

Piston travel due to thermal movements            5 inches (127mm)

Heat-up time                                                            10 minutes

Frequency of induced vibration…                       120 cycles/min.

Total allowable vibration movement without damage to pipe    15inches (3.8mm)

From the specifications table, the maximum allowable load for a 21/2“ (65mm) Vibrasnub is 12,000lbs (53.4kN). A 4″ (100mm) snubber can accommodate 30,0001bs (133.5kN). By using two (2) 4″ (l00mm) Vibrasnub snubbers, the vibration load on each one is 20,000lbs (89kN). well below the maximum load allowed.

The required rate of piston travel is 5″ (127mm) in 10 minutes, or 1/2 (13mm) per minute. Graph #1 shows the resistance shows the resistance to thermal movement al 1/2″ (13mm) per minute is Jess than 300Ibs (1.34kN) for each snubber unit (the point of intersection with the graph is actually off the graph, to the left). This low resistance would impart no undue strain on the piping system.

From Graph #3 it is seen that the total movement permitted by a 4″ (100mm) Vibrasnub under 20,0O0lbs (89kN) vibration load, at a rate of 120 cycles/min., is approximately 0.04″ (1.0mm). This is much less than the allowable movement of .15″ (3.8mm).

It is possible to use four (4) 2*/2″ (65mm) snubbers. But it is more practical to install only two (2) 4″ (100mm) snubbers and this is the proper solution.

Contact Dannenbaum LLC for a Hyspan Vibrasnub Catalog.