MARINE PRODUCTS
Loctite® Marine Chocking PC7202
Pourable Chocking Compounds
The use of pourable chocking compounds is a proven method for chocking of machinery. Before curing sets in, the liquid 2-compound epoxy based resin spreads out evenly in the mould thereby eliminating the need for machining badly corroded surfaces. After a curing period ranging from 24 to 48 hours (depending on the ambient temperature) the resin is fully cured and ready to accept the load of the machine and foundation bolts.
Features of Loctite® Fixmaster® Marine Chocking:
- no need for flat mounting planes
- large load bearing surface
- suitable for mounting directly on concrete
Loctite Marine Fixmaster is the commercial interesting alternative for Chockfast and Epocast and is type approved by all Major Classification Cocities like DNV, LRS, BV, GL, ABS etc.
Resilient mounts or flexible mounting
Resilient mounts (also called isolators) are used to reduce the level of noise and vibration on board. The amount of reduction is expressed in the isolation rate (in % of the unisolated machine). When selecting a resilient mount, attention has to be paid to the resonation frequency (critical rpm), the deflection of the mount under load (normally softer is better for isolation).
The available mounts in the market can be divided in mounts based on rubber and mounts based on steel springs.
Together with our partner Lo-Rez from Canada, a new serie of revolutionary mounts has been developed which is based on steel springs. Steel has superior isolation characteristics and does not have all the disadvantages, rubber has; like sensitivity for oil and creep (permanent setting over time).
The new mounts have the same footprint and building height as the mounts from RubberDesign and Vulkan, as per the following overview:
RD200 series - Vulkan T90 => Exakt CR1-H
RD300 series - Vulkan T60 => Exakt CR1-G
The mounts have class approval.
Mounting Kits
A mounting kit is an engineered package to chock and to mount any machine, consisting of:
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Chocking products (MecLev®'s or Loctite Fixmaster epoxy)
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Mounting products (bolts, nut, washers etc.)
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(pre-machined) Fitted bolts, if needed
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Spherical spacers (or spherical washers)
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Bolt torque calculation according Classification Society
Special Shims
Resilient mounted engines
We design and produce the shims needed for engines set up on:
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V-type resilient mounts
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Bar type resilient mounts
Stock is held for the following engine makes/types:
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Wärtsilä 38
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Wärtsilä 46
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MaK M25
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MaK M32
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MAN 28/32
Spherical washers/Spacers
Bolts normally have a 90° angle towards the mounting face of machine they fixate. The foundation however is in 99% of the cases not in parallel with the plane of the machine. The result is that the bolt is bending when tightening as the bolt head is touching at one point only. Consequently, the tightening torque is not converted in the calculated effect. The bolt will come loose in time.
A spherical washer between the bolt head and the foundation will absorb the difference in angle. In case where a short clamping length of the bolt is reducing the fixation eff ect of the bolt, spherical spacers are advised.
ExaktAlign's portfolio is comprising of both Spherical Spacers as Spherical Washers. The washers come is a standard execution (SW) and as Large washer with a bigger diameter (SWL).
Steel Spring flexible Couplings
Lo-Rez helical steel-spring flexible couplings provide low, constant and accurate torsional stiffness (within 8%), unchanged by age, wear, temperature, loading or vibratory intensity. Tooth separation points in geared systems can often be predicted precisely.
Some of the other features of Lo-Rez steel-spring Couplings
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Wide selection of torque/stiffness combinations within each of twelve different housing sizes (max. torque rating 942,000 Nm).
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Springs constantly under compression.
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Overload limit stops inside the springs prevent excessive spring stresses and coil clash during traversal of major criticals and during shock loading.
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No lubrication required (unless pilot bearing is used).
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Easy installation and in-place maintenance. Coupling can be inserted or removed without shifting associated equipment.
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Ample misalignment capacity with axial, angular and lateral stiffness proportional to torsional stiffness.
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Wide variety of arrangements possible.
RT Steel-Bolted rubber Couplings
The RT bolted rubber flexible coupling, most often used aft of the gearbox, provides dynamic mobility to a resiliently-mounted engine and minimizes bending stresses in the gearbox output shaft. Additionally, the RT coupling here has significant mechanical and acoustic attenuation, keeping engine and gear noise away from the low-speed shafting and bearings. Dynamic Magnifier values as low as 3.5 can be provided with high-damping elastomer elements.
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Two-directional (propeller) thrust capability
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Two-directional torque capability
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Low torsional, angular and radial stiffness for torsional tuning, misalignment and shock absorption
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Excellent noise-attenuating properties
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Good mechanical damping level
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Open design, facilitating inspection and maintenance
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A.B.S. & Lloyds Registry approved
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Shock tested to U.S. MIL spec MIL-S 901C (MOD.)
Steel spring Vibration Isolators
General description
Lo-Rez Steel Spring Vibration isolators incorporate a limit stop to prevent excessive vertical motion and rocking motion of isolated equipment in ships. The neoprene bumpers can be easily adjusted to accommodate the actual working height of the isolator as well as to limit the random motions to any desired degree.
The leveling screw and the additional cap screws securely fasten the equipment sub-base to the top of the isolator. As with all LO-REZ isolators there are neoprene dampers inside each end of the isolator (adjustable at one end) to withstand longitudinal and lateral (including crash) forces – so obviating the need for any external chocks.
BR-LS
The BR-LS isolator, available in 5 housing sizes, load capacity range from 225 N to 71 kN (see brochures).
BR-T (Thrust)
The BR-T isolator, available in 3 housing sizes, load capacity range from 3.5 kN to 51 kN (see brochures).
The BR-T isolators have special flexible thrust carrying devices which permit them to carry full thrust load without “locking up” so that they are capable of providing effective isolation of the engine-generated vibration over the entire speed range.
Soft Mount Package
The “Soft-Mount” package was developed to provide excellent vibration and noise isolation for propulsion engines with flanged on gearboxes. The system is comprised of the BR-T type isolators that are designed to carry full propeller thrust without locking up (thus providing isolation over the entire speed range) and the RT coupling which is also designed to carry full propeller thrust, both ahead and astern.
The RT coupling provides:
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adequate flexibility to reduce the bearing loads in the shafting and gearbox under dynamic motions of the engine
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reduces noise and vibration produced from the engine and gear from being transmitted down the propeller shaft into the structure
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absorbs propeller thrust pulsations.
More information on the BR-T isolator and the RT coupling can be found in the leaflet on this. Some 400 vessels have been fitted with this system.
Torque Limitters
When utilizing Torque Limiters, gone are the problems associated with:
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slow reaction electrical overloads
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shear pins which give a wide torque variation and a slow re-engagement of equipment
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rapidly overheating slip clutches
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Nothing breaks, nothing to replace.
TL Torque Limiters Features:
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Positive drive, no slip
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Maintains shaft-to-shaft timing alignment, even after re-engagement
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Rapid easy re-engagement
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Full bi-directional operation
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Release torque setting maintained
Torque Limiters can be combined with Reverse Thrust or Steel Spring couplings to provide a fail-safe shock absorbing/release device for marine applications (like dredging).