In addition to Bladder, Piston and Diaphragm accumulators, HYDAC offers a fourth series – Metal Bellows Accumulators. A metal separating element is used between the fluid and gas side of the metal bellows accumulator. This makes it virtually gas tight, eliminating elastomer separating elements and seals from the accumulator and providing a solution for some very challenging accumulator pulsation application conditions.
The recently developed solution from HYDAC is the Metal Bellows Accumulator. Instead of a bladder or diaphragm, a metal bellows is used as the flexible separating element between fluid and gas. The metal bellows is resistant to all conventional fuels over a very wide temperature range. Heavy fuel oil at temperatures from -85 °F to 320 °F is is easily handled these dampers. The metal bellows is welded to the other components and is therefore completely gas tight. It is able to expand and contract inside the accumulator without any friction or abrasion and it can operate for a very long period of time (years) with a single adjustment. Monitoring and maintenance for this type of damper is therefore reduced to a minimum.
Construction
Metal Bellows Accumulators are available in two different styles:
A diverting block is built into the fuel side of the damper which forces the fuel directly into the accumulator, thereby increasing the damping efficiency considerably. If two dampers are fitted to the fuel system (in both supply and return line), no pressure fluctuations can leave the engine before passing through one of the metal bellows dampers.
If a conventional accumulator can no longer perform its function, this can lead to expensive maintenance and repair work. We can offer a retrofit alternative - Replacement without the need for modification.
Features
There are two different design types of metal bellows; convoluted (formed) and diaphragm (welded). Each has a slightly different design and performance advantages also vary.
Convoluted bellows (formed)
Diaphragm bellows (welded)
Areas of Application
Industry Sectors
Technical Information
Specification | Flange Connection Design | Threaded Connection Design |
Series | SM50P | SM50 |
Max. design pressure | 725 psi | 725 psi |
Max. working pressure | 43.5 psi - 174 psi | 43.5 psi - 174 psi |
Max. pre-charge pressure at Tmax | 58 psi | 116 psi |
Design Temperature range | 14 F˚ - 320 F˚ | |
Operating media | Diesel and heavy fuel oil, biofuels | |
Size | 0.5 - 3.8 L | 0.5 - 1.6L |
Effective gas volume | ≈0.5 L (nitrogen) | |
Gas side pre-charge fluid | 0.6 L (ethylene glycol) | 0.3 L (ethylene glycol) |
Fluctuating volume | max 0.04 L | |
Material | Carbon steel (primed externally) | |
Design and Approval | e.g.: PED, ABS, DNV, LR, BV, GL, RMRS | |
Fluid connection | Diverting block SAE 1-1/4” Diverting block SAE 2” Diverting block SAE 3” | 2” BSP (female) or with adapter alson for 1 1/2” BSP (male) |
Gas connection | M28x 1.5 for Universal Charging and Testing Unit - FPU-1 | |
Mounting position | vertical (gas connection at top) | preferably vertical (gas connection at top) |
Weight | 48.5 - 73lbs | 20lbs |