The post Trident / Triton – Rotor-Tug appeared first on .
]]>The Seabulk Towing , Robert Allen designed Trident Rotor-tug built by Master Boat Builders, was designed to be the most manoeuvrable towing vessel in the United States. The challenge was to provide superior isolation performance for the Thompson Tractor supplied Caterpillar 3512C marine propulsion engines, allowing the vessel to operate at optimum performance and capability.
Christie & Grey combined our TSC T10 isolators with a Centa CX-72 coupling to provide a vertical isolation efficiency in excess of 96%. Each of the port, starboard and aft engines were individually analysed using our in-house six degrees of freedom programme, to ensure that all operating conditions were considered and the optimum selection was provided.
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]]>The post Heron Tower, London appeared first on .
]]>2 stage system using Open Spring Mountings and MD/3 Silicon Fluid filled Viscous Dampers between each generating set and a common intermediary steel support frame. The steel support frame is isolated from the main structure by Studflex Rubber Pads in a mixture of sizes and rubber compounds. The 2 stage system was then covered by an acoustic enclosure designed by Powerplus Engineering Ltd in Colchester, a company we have worked closely with on a number of projects.
The Arup Acoustics Specification called for Spring type isolators with a static deflection greater than 50mm fitted with ancillary dampers to prevent excessive movement as the machine passes the resonant frequency of the mounting system.
10 No. OS75/2000 Open Spring mountings (75mm deflection @ 2000kg) supporting 1511.6kg per mounting.
56.7mm deflection achieved on each mounting giving an isolator natural frequency of 2.09Hz.
Vertical Isolation Efficiency of 99.29% at 1500 RPM.
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]]>The post MV Jackie Brown appeared first on .
]]>ACBL M/V Jackie Brown was originally installed on another manufacturers isolation mountings, which did not meet the performance and reliability requirements for the customer.
Christie & Grey were tasked with providing a new improved mounting system based upon the limitations this not being a new installation, limiting the available space for our TSC range of mountings.
Christie & Grey, with the installation expertise of National Maintenance and Alignment, delivered superior isolation performance by installing our TSC T1 isolators in-conjunction with proof plates and soleplates to aide installation and in-service maintenance.
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]]>The post MV Ricky Hughes appeared first on .
]]>ACBL M/V Ricky Hughes was originally installed on another manufacturers isolation mountings, which did not meet the performance and reliability requirements for the customer. A complete solution was required to both replace the mountings and also improve the functionality of the installation.
Christie & Grey were tasked with providing a new improved mounting system based upon the limitations this not being a new installation, some bespoke adaption was required to provide a higher performing system.
This vessel operates 8,000 hours a year and avoiding down time is critical.
Incorporating both off the shelf components and custom adapter plates to fit within the existing footprint parts were shipped to allow replacement on short order to meet the customers schedule. The system is designed to allow for simplified maintenance, while improving isolation performance and significantly reducing creep rates and as a result less maintenance and significantly increased uptime.
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]]>The post Data Centre, UK appeared first on .
]]>Customer installed three generator sets directly to structural slab, utilising only the integral Rubber Mountings provided by the Generator Set manufacturer. Subsequent acoustic testing showed that
“The PPV limit of 5mm/s is selected as a value that is deemed to be achievable at this stage. BS 5228- 2, Code of practice for noise and vibration control on construction and open sites, has been selected and the most appropriate benchmark for target values due to the intermittent nature of the running of the generators. Tables B.1 and B.2 of BS 5228-2, define a PPV value under 5 mm/s should be tolerable for the likely operation duration of the generator and be below the value where cosmetic damage is expected. It should be noted that this value will still be noticeable and above standard limits for a working environment”.
The actual measured PPV values in the three orthogonal directions were up to 23.7 mm/s, well in excess of the 5 mm/s benchmark
Christie & Grey provided our unique Open Spring and Damper solution providing 50 mm nominal deflection. In designing this solution we did not ignore the existing Rubber mountings, instead we used them in our solution, checking and confirming the expected performance using our bespoke rigid body analysis programme ensuring all twelve degrees of freedom did not create any magnification and ensuring all mountings both Spring and Rubber worked together in harmony.
The highest measurement of 23.7 mm/s was reduced to 2.7 mm/s and the new highest measurement seen was 5 mm/s, exactly on the benchmark value.
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]]>The post Tidewater Barge MV Crown Point appeared first on .
]]>Typical adjacent space noise levels : 110 dBA
Target noise level : 65 dBA in vessel.
Actual noise levels : 60 dBA at full engine power (measured in crew accommodation).
A combination of clever ship design, logical space layout, efficient insulation and our TSC range of isolators providing 95%+ vertical isolation efficiency.
Note: Our mounting systems have shown to provide a 110 dBA to 70 dBa reduction in adjacent spaces without additional acoustic treatment.
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]]>The post Holland and Holland Shooting Club appeared first on .
]]>The introduction of a building extension to the Ducks Hill shooting club provided the need to install a Stud Rail System (SRS) floating floors to the kitchen, offices, WC and plantroom areas of the building to reduce the potential noise impact from the shooting range below.
Christie & Grey analysed each floating floor area individually as different loads requirements were applied depending upon the function of the space. The Acoustic Floating Floors were designed to achieve a static deflection of 6 mm under dead load with an additional 2 mm for the live load applied. Careful consideration was taken on those areas where there was static heavy furniture, walls and water tanks which required additional Studflex Pads to provide sufficient support.
We calculated our system would provide a theoretical performance based upon a deflection of 8 mm under live load condition, producing a natural frequency of the Studflex Pads of 6.63 Hz for the lighter Kitchen/Office areas (100 mm floated slab) and 6.93 Hz for the heavier Plantroom area (150 mm floated slab).
When including the 50 mm air gap between the floating floor and structural slab. The related air stiffness increases the natural frequency of the system, Studflex Pads, air gap and 100 mm / 150 mm floating floor slab to 11.40 Hz and 10.51 respectively.
Holland & Holland employed the following build up of materials to provide a 50 mm air gap and 100/150 mm floated slab dependant upon area.
Due to the existing structural steel work and drains for the Kitchen and WC areas, there was a significant number of penetrations through the SRS floating floor. Careful design and execution was crucial to avoid short circuit and maintain the integrity of the floor.
Christie & Grey provide detailed installation drawings to precisely position our Studflex pads to ensure an equal deflection throughout the SRS floating floor system.
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]]>The post The Curzon Cinema, Oxford appeared first on .
]]>The introduction of a five Curzon Cinema operated screens into the redeveloped Westgate Shopping Centre to provide new state-of-the-art cinemas from a chain which specialises in independent artistic films. Representing only the fourth of its kind outside of London. The introduction of which will bring the number of cinemas in Oxford to six.
Christie & Grey have proposed our Stud Rail System (SRS) floating floor to meet the specification of Holtz Acoustics for an Acoustic Floating Floor, to achieve a Natural Frequency of 9 Hz or less with a 100 mm air gap, under the dead load only. In addition to providing Acoustic Wall Ties and Acoustic Ceiling Hangers to provide a true box-within-box solution.
Using the load requirements set out by Paul Owen Associates for the cinemas which included the provision for a 150 mm of concrete slab and an additional dead load requirement for rake seating, plus 5 kN live load.
We calculated our system would provide a theoretical performance based upon a deflection of 7.4 mm under live load condition, producing a natural frequency of the Studflex Pads of 6.87 Hz.
When including the 100 mm air gap between the floating floor and structural slab. The related air stiffness increases the natural frequency of the system, Studflex Pads plus air gap plus 150 mm floating floor slab to 8.25 Hz.
The Curzon Cinema employed the following build up of materials to provide a 100 mm air gap and 150 mm floated slab.
In addition, Acoustic brickwork and internal partition wall ties are designed to provide structural stability whilst attenuating noise and vibration between cavity walls.
FInally, Studflex wall isolation pads in combination with Christie & Grey isolation washers, wall head rubber isolation strip were employed together with the acoustic wall ties to provide a complete wall isolation solution.
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