ASA Bladder-type accumulators consist of a seamless cylindrical pres- sure vessel made of high-tensile steel.
The accumulator is subdivided into a gas and fluid side by an elastic bladder mounted in the interior of the vessel.
The bladder is charged with nitrogen to the specified gas charge pressure P0 by means of gas valve.
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.
Gas valve consists of external caps, sealing cap, filling valve, gas valve body and rubber coated washer. These parts can be replaced separa- tely.
The nameplate shows the technical data and features of the hydraulic accumulator.
MAX OPERATING PRESSURE (PS): 4000 PSI PRESSURE TEST (PT): 1.3 x PS
NOMINAL CAPACITIES: 1/4 – 1 – 2.5 – 5 – 10 – 15 gallons WORKING TEMPERATURE: -40 ÷ +200 °F (-40 ÷ +93 °C) COMPRESSION RATIO (Po : P2): max. 1 : 4
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 (SA 372 grade E class 70) painted with rust inhibitor RAL 8012
– nickel coating 25 – 40 μ
– internal and external coating with RILSAN th. 0.6 mm
– 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 = Nitrile for hydrocarbons
– K = Hydrogenated nitrile (HNBR) – B = Butyl (IIR)
– E = Ethylene-propylene (EPDM) – N = Chloroprene (Neoprene)
– Y = Epichlorohydrin (ECO)
– V = Fluorocarbon (FPM)
See Table 3.5c and/or Chapter 1.5
FILLING VALVE CONNECTION:
– 5/8”-UNF std – 7/8” UNF
– 1⁄4” BSP
FLUID PORT CONNECTION: see Table 3.5dc – 3.5df – 3.5eb – 3.5ec FLOW RATE: see Table 3.5db
WEIGHT: see Table 3.5db – 3.5df