Effective vibration isolation technology for suspended equipments

Spring hangers are vibration isolation equipments used for providing vibration isolation for suspended equipment. They offer a combined solution for both vibration isolation and for high and low frequency noise. These spring isolation hangers are often used in suspended equipments like the piping and ductwork with no lateral loads and no change in operating weight.

The application of spring hangers in suspended piping and ductwork helps in preventing vibration transmitting to the surrounding structure. There is wide range of Isolation hangers available in the market, designed in housed cages and encompassing rubber, spring and rubber and spring combination hangers. These spring isolation hangers prevent your machinery from getting damaged with their vibration-control hangers and isolators. The vibration isolation spring equipments are ideal for securing heavy pipes or equipment to limit noise and vibrations during their operations. The hangers effectively isolate transmission of vibration or any form of structural sound. Further, these spring hangers are known to prevent many installation errors as it permit a degree of movement of piping which eliminates the need of a flexible hose connection. In addition to this, the vibration spring hanger isolators will also manage the expansion issues of riser pipe lines.

The market offers a wide range of spring isolators designed to minimize structural transmission of noise and vibration generated by almost any application. With a wide range of hangers available with coil springs for low frequency applications, rubber-in-shear for absorption of sound and shock, this equipment are perfectly designed to offer maximum isolation. Besides, these spring hangers are sturdily built for long rugged use and maximum provision of isolation equipment.

Typical application of spring hangers –

Spring hangers are isolation equipments typically used in suspended equipments which include air handling units, axial fans blower, cooling and heating equipment, ductwork exhaust system, fan coil units, pipe work platform, pumps, ventilation and much more.

Go in for seismic isolators and spring hangers for your buildings

Seismic restrained isolator: The seismic spring mounts consist of a metallic housing that restricts the vertical and horizontal movement of the supported equipment during a seismic impact. The neoprene elastomer element is fitted in series with the spring coil. It prevents the metal short circuiting between the supporting member and housing. The seismic vibration isolators are designed to withstand forces of 1G magnitude along the horizontal and vertical planes without any yield or failure. The seismic vibration damping mounts function normally as vibration isolators under normal operating conditions.

The features of the seismic spring isolator can be summarized as:

  • Restraint along all major axis with physical limits in the vertical direction
  • Free height and operating height are fixed
  • Adequate rust protection for steel parts and spring coils
  • Easy replacement of spring coils in the field

Seismic spring mounts: The floor mounted seismic spring dampers are used for indoor and outdoor equipment isolation. The welded housings in the seismic spring mount for

Seismic spring mounts:

Seismic spring mounts:

deflection, limit the lateral and vertical movement. The typical use of seismic spring isolators is for cooling towers, chillers, air handling units, and base-mounted fans. The seismic spring is epoxy powder coated while the steel parts are hot dip galvanized for a long service life. The seismic brackets are also used along with other seismic restraint products for better results.

Spring isolation hangers: The vibration hangers are housed in a stamped or welded hanger bracket. The color coded coil spring indicates the load and deflection characteristics of the spring hangers. The metal to metal contact is prevented by the use of a molded fiberglass insert or an elastomer element. The spring in the sound isolation hangers has lateral spring stiffness equal to the rated vertical stiffness. The spring hanger allows for support rod misalignment through a 30-degree arc.  The vibration hanger is suitable for isolation of low speed suspended mechanical equipment like fans and pumps etc.

Piping spring hangers: The anti-vibration hanger is recommended for use around critically quiet areas for the isolation of vibration and noise produced by suspended piping and

Piping spring hangers

Piping spring hangers

ductwork. The pipe support and hangers prevent the vibrations from getting transmitted to the supporting structure. The sound isolation hanger’s rubber absorbs the high-frequency vibrations while the spring takes care of the low-frequency vibrations. The spring hanger extensions and spring brackets are used in tandem with the pipe spring hangers for ease of installation and improving the performance of the isolation system. The swing hangers with spring link are used in the application where the fluid temperature causes the thermal expansion of the piping.

Andre HVAC International Inc. has been providing solutions to builders and designers for adequate seismic protection since it came into existence in 2003. It also has a wide range of products in the spring hanger pipe support and spring ceiling hanger segment used for acoustic isolation in buildings. AHI provides the support to the customers in the selection of the anti-vibration hangers and other seismic restrained isolators.

Spring hangers and their wide range of application in industrial and mechanical equipment’s

Spring hangers or anti-vibration hangers are equipment that are typically used for suspended piping and duct work running from mechanical equipment to prevent vibration transmitting to the surrounding structure. There are a wide range of Isolation hangers, Spring hangers and their wide range of application in industrial and mechanical equipment’susually housed in cages and encompassing rubber, spring and rubber/spring combination hangers that are available for various applications.

Anti-vibration suppliers offer wide range of isolation hangers including spring ceiling hangers, pipe spring hangers, HVAC hangers etc. for isolation of suspended ceilings. But selecting the correct isolation hanger is essential for effective dampening of vibration from the application. It is usually advisable to refer to the Isolator selection guide to obtain the necessary static deflection, then select the isolation hanger required according to equipment load. For isolation hangers using only rubber elements, the dynamic factor also needs to be taken into account.

Vibration Isolation Hangers are designed to reduce the transmission of vibration and noise produced by suspended equipment and piping. These spring ceiling hangers incorporate a high deflection color-coded spring element that offers a noise isolation pad which is assembled into a stamped or welded spring bracket. To assure stability, the spring element has a minimum lateral spring stiffness of 1.0 times the rated vertical stiffness. Spring isolation hangers are available in deflections from 1″ to 4″ (25 to 102 mm) and in capacities from 35 to 3850 lbs. These anti-vibration hangers are effective in isolating vibration produced by low rpm equipment. Anti- vibration hangers are usually recommended for isolation of vibration produced by suspended mechanical equipment, like exhaust fans, ductwork, piping, etc.

Application of spring hangers

Spring ceiling hangers are equipment’s recommended too be used in isolating suspending sources of inaudible frequency vibration, located near vibration-free areas. Suspended mechanical equipment such pipes, fans, cabinet fans, and piping and ductwork in close proximity to mechanical equipment are typical uses of such hangers. These hangers are available in a wide range of load and static deflection selections and can be customized for adaption to wire or strap suspension systems, and spring may be preloaded for ease in erecting piping at a fixed elevation.

Features of Spring Hangers

  • Spring hangers offer isolation from noise as well as vibration sourced from various applications
  • Spring Hangers are large diameter steel springs housed in rectangular steel housings.
  • The Standard design allows angular hanger misalignment.
  • Also thesespring hangers feature rubber cup in place of metal cup in the bottom of the bracket which eliminates metal to metal contact& give better efficiency.
  • Springs hangers are galvanized& not painted,thus offering better rust protection.

 

Selection of right spring hangers for isolation of mechanical equipment

Spring hanger Isolators are vibration dampers that consist of high deflection, free-standing, unhoused, large diameter and laterally stable steel springs that are assembled into an upper load plate and leveling assembly. For assured stability, the spring hangers have lateral spring stiffness that are greater than 1.0 times the rated vertical stiffness. These spring isolation hanger are designed to provide a minimum of 50% overload capacity. Also they are polyester powder coated for a lasting durability. Spring hanger isolators are available in higher deflection and greater load capacities for better isolation.They are highly effective for control of both high and low frequency vibration produced by various applications like reciprocating air or refrigeration compressors, pumps, packaged air handling and air conditioning equipment, centrifugal and axial fans, internal combustion engines, etc.

Spring hangers are an integrated part of the Piping Industry. The use of spring hangers in supporting pipe weights is a known phenomenon to every piping engineer. When rigid supports are not taking load due to the thermal movement or rigid supports are effecting the equipment connection piping engineer’s advice for the use of a pipe spring hanger to share some of the loads and to keep the piping system safe. Selecting an appropriate type of hanger to support any given application is governed by the individual piping configuration and job requirements. In general there are two main types of spring hangers.

a) Variable Spring Hanger wherein the Loads vary throughout its operating range.

b) Constant Spring hanger: wherein the Load remains constant throughout its operating range.

Constant support hangers are used to support structures and components like pipes, vessels and other such applications that experience vertical movement. These hangers provide support at critical locations of in structure in a way that the temperature dependent deformation of the structure does not produce any excess stress to the structural system. A constant support isolation hanger provides a constant force on the structure so that it does not experience any extra resisting forces from the support. Constant resistance to a moving load is achieved by balancing the moment of the moving structure produced by the force of a compressing/decompressing spring from a common pivot point.In designing a constant support hanger, minimum variation of the load is optimized via selecting the proper arm lengths of the external force, the spring force, and the spring constant for a given total displacement of the external load.

Variable Spring Hangers are used if vertical movement of the piping aren’t restricted by rigid hangers. The unique construction of this equipment is particularly suitable in severe corrosive conditions. Special Variable Hangers or Supports are designed to suit customer’s specific requirements. The criteria for selecting Variable Spring Hangers are based on three conditions and they are as follows

  • Based on the load and displacement for which the support has to cater
  • Depending on whether the physical arrangement of the support be it top hanging or base mounted.
  • Depending on the allowable deviation in load that the pipe can sustain.