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Vibrasnubs & Flexible Strut Joints2021-07-19T20:09:47+00:00

Project Description

Barco Vibrasnubs & Flexible Strut Joint

Vibrasnubs

In this paragraph, I’m going to tell you about vibrasnubs and flexible strut joints. Firstly vibrasnubs and flexible strut joints are used to support structures and system components. Secondly, they restrain unwanted structural movement. Also, they accommodate the high tensile and compressive load. Next, vibrasnubs and flexible strut joints absorb dynamic vibration and shock loads. Lastly, a vibrasnub and a flexible strut joint can handle compound motion due to torque and rotation.

Moreover, when used together, the “Ball Type” Flexible Strut Joints provide rigid structural support. Thus able to resist high tensile and compressive loads. And it allows lateral, angular, and rotation movement. Also, the precision ball and socket construction provide a maintenance-free rigid connection to brace process equipment, for instance, piping, pressure vessels, boilers, and tanks.

Furthermore, strut joints combined with vibrasnub hydraulic vibration snubbers form an assembly that absorbs tensile and compressive shock and vibration loads while allowing gradual movements such a thermal growth. Unfortunately, people often confuse the vibrasnubs and snubbers.

“Ball Type” vibrasnubs and flexible strut joints provide the direct method to support structures and system components. Also, restrain unwanted structural movements. As well as accommodate high tensile and compressive loads. Furthermore, absorb dynamic vibration and shock loads. The vibrasnub has a ball joint attached to the end of it. Often people confuse a ball joint with a ball valve.

Handle compound motion due to torque and rotation.

Strut Joints and Vibrasnubs

  • Advantages:  “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 is required.
  • Simple: Simplifies structural designing and eliminates the need for special struts, tie-rods, or clevis-and-pin arrange­ments. They are not as flexible and are subject to low stress and binding.
  • Safety: High load carrying capacity for reliable service in severe conditions. He was, moreover, combined with the easy calculation of prop­er sizes to promote safety in structural design.

“Ball Type” Flexible Strut Joints may be applied for static or dynamic loads.

They are rated for tensile or compressive loads. The most common uses are:

  • Structural sway bracing for hot stacks and pipes.
  • Supports or hangers for horizontal piping.
  • Stability supports for tall or slender towers, structures, or vessels.
  • Restraints to direct and control thermal expansion away from components that should not be stressed. For instance, turbine nozzles and pump flanges.

“Ball Type” Flexible Strut Joints are more straightforward, cheaper, and less bulky than other restraints—for instance, slide plate guides, A-frames, and clevis-and-pin arrangements.

Vibrasnub Vibration Snubbers

The vibrasnub snubber is designed to be used to control dynamic vibration on and shock loads. For continuously applied static loads, use flexible strut joints. Moreover, vibrasnub hydraulic vibration snubbers function as a stop or restraint for dynamic vibration and shock loads. Therefore, these rapid movements may (or may not) be accompanied by slower natural tendencies, like thermal expansion or contraction. Also, quick vibration movements are absorbed by the snubber assembly. In addition, passing hydraulic fluid through a restricted orifice in the piston of the snubber cylinder makes a more gradual thermal movement. Next, the “Ball Type” Flexible Strut Joints on each end of the assembly permit a +/-10° alignment movement to eliminate binding. Increased angulation available in some sizes.

Advantages of Vibrasnub Hydraulic Vibration Snubbers

  • 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 of testing and installed use.
  • Fast, positive action — Resist and dampen shock and vibration loads instantaneously.
  • Eliminates binding — Permit +/-10° angular and conical movement of supporting structure while dampening vibrations and shock loads.
  • Handles slower, thermal, and seismic movements.
  • Only a nominal pressure drop was created across the bypass orifice against slower thermal movements.
  • Simplifies design and installation — Compared to other more complicated motion control systems.
Vibrasnub Installation

In this paragraph, I’m going to tell you how to install vibrasnub snubbers. Firstly you can install the vibrasnub in any position. Secondly, use them in pairs with an acute (less than 90°) interior angle. Also, if only one snubber is installed, it must be installed directly in line with the thrust force. Finally, guide the moving member to eliminate any possible lateral movement.

Also, weld the Strut Joints at the end of each vibrasnub assembly to pipe or steel structure. Moreover, anchor points should be designed to withstand the total loading and minimize secondary vibrations.

Isolate the vibrasnub cylinder from heat (or hot member of structure). Furthermore, the pipe extension should be towards the heat source to prevent cylinder temperature from exceeding +150°F (•66°C).

Available Option.

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

Vibrasnub Catalog

BARCO STRUT JOINTS AND VIBRASNUBS

This is a rough copy of the Vibrasnub Catalog.

Advantages: 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 is 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 the easy calculation of proper sizes to promote safety in structural design.
  • 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.

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:

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

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. Better charts are available in the vibrasnub catalog.

BARCO STRUT JOINTS AND VIBRASNUBS

Inches3/4111/2235610
mm(20)(25)(40)(50)(80)(125)(150)(250)
Loading: Lbs.7,00010,00014,50020,00040,00080,000120,000250,000
(kN)(31.2)(44.5)(64.5)(89)(178)(356}(534)(1112)
Table 3: Dimensional Data
Assembly

Part No.

Size:

In. (mm)

ABCDFGHJKLShipping Wt:. Lbs. (kg)
BB-35500-163/4×1 (20X25)3.50

(88,9)

1.75

(44,5)

2.63

(66,8)

.218

(5,5)

1.DS (26,7).179

(4.5)

1.32

(33,5)

3.0

(1,4)

BB-35500-201×1-1/4 (25X32)4.25

(108,0)

2.12

(53,8)

3.25

(82.6)

.250

(6,4)

1.32

(33.5)

.191

(4.8)

1,66

(42.2)

6.0

(2,7)

BB-35500-321-1/2×2 (40×50)5.75

(146,1)

3.00

(76,2)

4.25

(108,0)

.200

(5,1)

1.90 (4B,3).218

(5.5)

2.38

(60,5)

12.5

(5,7)

BB-35500-402×2-1/2 (5DX65)6.00

(152,4)

3.00

(76,2)

5.00 (127,D).218

(5,5)

2.38

(60,5)

276

(7.0)

2.88

(73,2)

49.0

(8,61

BB—3550D—643×4 (80×100)6.62

(168,1)

3.25

(82,6)

6.ID (165,1).300

(7,6)

3.50

(88,9)

.337

(8,6)

4.50

(114,3}

35.0

(15,8)

BB-35000-665×6 (125×150)7.50

(190,5)

3.63

(92,2)

12.50

(317,5)

.375

(9,5)

10 63

(270,0)

3/4’”-1012

12

5.56

(141,2)

.432

(11,0)

6.63

(168, )

120.0

(54,5)

BB-35000-686×8 (15Ox200)8.88

(225,6)

4.50

(114,3)

5.00

(381,0)

.432

(11,0)

13.0

(330,2)

7/8″-912

12

6.63

(168.4)

.500

(12,7)

8.63

(219,2)

225 0

(102,2)

BB-35000-7210×12 (25Ox300)14.38

(365,2)

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

(21,4)

19.25

(489,0)

1-1/4’”-720

20

10.75

(273,1)

.687

(17.4)

12.75

(323,9)

650

(294,8)

How to Order:

Determine tensile or compression load for your application. Then, select the ball end size to handle this load from.

Design and Engineering:

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 50F (343C).

The total load to which the joints will be subjected will determine the selection of the proper size. The total load includes:

  • Normal operating load(s).
  • Also, sudden or wind-shock loads.
  • As well as the forces or loads involved in decreasing the distance between the supporting and supported 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 the design.

These deflections can be minimized by

  • Make the rigid strut between the joints as long as possible, consistent with good structural practice and considering the acceptable L/R ratio.
  • Install the strut arrangement in the cold position so that this deflection occurs only during heat-up or cool down.

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

BARCO STRUT JOINT AND VIBRASNUB

Please visit us for the original Vibrasnub Catalog. It has the figure pictures.

BARCO STRUT JOINTS AND VIBRASNUBS

Vibrasnub catalog will explain better. 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. The snubber assembly absorbs quick vibration movements. 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 in some sizes.

The Vibrasnub snubber is designed to be used to control dynamic vibration and shock loads. For continuously applied static loads, use Barco Ball Type Flexible Strut Joints.

Advantages:

  • First, lower cost: Simplicity and long life, with minimal maintenance, compared to other types of vibration and shock control mechanisms.
  • Second reliable, long service life: Proven superior through years of testing and installed use.
  • Next, positive action: Resist and dampen shock and vibration loads instantaneously.
  • After, permit +/-10° angular and conical movement of supporting structure while dampening vibrations and shock loads.
  • Finally, it 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. However, they should be used in pairs with an acute (less than 90°) interior angle. If only one snubber is installed, it must be installed directly in line with the thrust 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 points 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).

Any applications laid outside of the range of this data should be referred to someone.

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.
  • Neoprene boot protects the exposed piston rod area against dust, weather, and corrosive atmosphere.
Features:
  • 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-based 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: The other joint has half pipe coupling for connection to pipe extension and is non-rotating to keep cylinder parts on top.
  • Shipment: All parts (except extension pipe) snipped in one (1) container, a cylinder filled with fluid.
  • For fabricated assemblies complete with extension pipe, inquire.
  • Cylinder Repair Available.
Table 4 Specifications
Vibrasnub Size: In.

(mm)

1-1/2″

(4Omm)

2-1/2”

(65mm)

(100mm)
Nominal Pipe Size of Extension: In.

(mm)

2″

(50mm)

2-1/2″

(65mm)

(l00mm)
Maximum Load:

Lbs

(kN)

7,000

(31.2)

12,000

(53.4)

30,000

(133.5)

Frictional Resistance:

Lbs

(kN)

7f (.0Z)100

(.45)

200

(.90)

Shipping Weight:

Lbs

(kg)

70

(32)

90

(41)

175

(79)

Table 5 Dimensional Data
Size:PartTravelABCDEFGGHJKoverall dimension with a full load
In(mm)NumberIn(mm)Min.MaxMin.•      Max.-
1-1/2BB-35001-24t/-d3.Z51.664.251.002.5022.506.0096.009.002.002.0041.+5131.75
(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)
2-1/2BB-35001-40+/-64.252.JB5.761.133.0028.008.06112.0610.692.502.5052.51156.51
(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)
4.0BB-35001-64+/-65,00Z.886,001.50+.7529.196.75181.2511.634.00^.0053.56228.06
(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 is available on special request.

The maximum overall dimension is 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 the 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 the point of snubber attachment without damage to stack 125 inches (3.2mm).

From the specifications table, it is seen that one 2“ (65mm) Vibrasnub with a maximum allowable load of 12,00Dlbs (53.4kN) is sufficient. However, two are recommended for 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: This 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 is permitted by a two 1/2″ (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). Suppose the frequency of vibration had been 30 cycles/min. The total permissible movement would then be approximate. (4.6mm) which is greater than that allowed for a 2 1/2“ (65mm) unit. 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 is directed upwards.

Problem: Eliminate excessive vibration in the pipe and provide for differential thermal movement of the line 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 2 1/2“ (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 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 chart, 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″ (65mm) snubbers. But it is more practical to install only two (2) 4″ (100mm) snubbers, which is the proper solution.

Please get in touch with Dannenbaum LLC for an RFQ.