Bladder low pressure ASBL and ASBT type accumulators consist of a welded cylindrical pressure vessel made of steel.
The accumulators are subdivided into a gas and fluid side by an elastic bladder mounted in the interior of the vessel.
In the ASBL type, the liquid is also inside the bladder.
The transfer accumulator ASBT type is designed especially for connec- ting to nitrogen bottle. A diffuser rod prevents damages to the bladder when the accumulator works.
Nitrogen bottle used as back-ups increase the gas volume in the accumulator. This means that smaller accumulators can be used for the same gas volume and costs can be reduced.
When the fluid is pressed into the accumulator, the gas in the bladder is compressed and hence the pressure increased. The gas volume reduces and on the fluid side, the fluid can flow into the accumulator. As soon as the pressure on the fluid side falls below the gas pressure, the accumu- lator is emptied.
Oil valve is provided in the oil port of the bladder-type accumulator and closes when the pressure on the gas side is higher than the one on the fluid side. This prevents draining of the bladder into the oil channel and thus the bladder from being destroyed.
When the minimum operating pressure is reached, a small oil volume is to be maintained between the bladder and the fluid volume (approx. 10% of the nominal capacity of the hydraulic accumulator), in order that the bladder does not hit the valve during every expansion process.
The gas valve body of ASBL type accumulator is complete with anti-ex- trusion in addition to the rubber washer and locknut.
The gas valve body of ASBT type accumulator is complete with diffuser rod in addition to the rubber washer and locknut.
These parts can be replaced separately.
The nameplate shows the technical data and features of the hydraulic accumulator.
MAX OPERATING PRESSURE (PS): 60 bar
PRESSURE TEST (PT): 1.43 x PS
ASBL: 0.7 – 1 – 1.5 – 3 – 5 – 10 – 15 – 20 – 25 – 35 – 55 litres ASBT: 1 – 1.5 – 3 – 5 – 10 – 15 – 20 – 25 – 35 – 55 litres
WORKING TEMPERATURE: -40 ÷ +150 °C FLUID VISCOSITY RANGE: 10 ÷ 400 cSt RECOMMENDED VISCOSITY: 36 cSt FLUID CONTAMINATION DEGREE:
class 21/19/16 according to ISO 4406/99
– carbon steel shell painted with rust inhibitor RAL 8012 – nickel coating 25 – 40 μ
– stainless steel AISI 316L
– phosphated or galvanized carbon steel in compliance with Directive 2002/95/EC (RoHS) to resist to corrosion
– stainless steel AISI 316L – nickel coating 25-40 μ
– P = Nitrile rubber (NBR)
– F = Low temp. nitrile rubber
– H = Nitril for hydrocarbons
– K = Hydrogenated nitrile (HNBR) – B = Butyl (IIR)
– E = Ethylene-propylene (EPDM) – N = Chloroprene (Neoprene)
– Y = Epichlorohydrin (ECO)
– V = Fluorocarbon (FPM)
See Table 3.4c and/or Chapter 1.5
GAS VALVE CONNECTION: see Table 3.4db – 3.4dd
FLUID PORT CONNECTION: – see Table 3.4db – 3.4dd – 3.4eb 3.4ec – 3.4fb
FLOW RATE: see Table 3.4db – 3.4dd WEIGHT: see Table 3.4db – 3.4dd