(measured with HLP46, ϑOil = 40 ±5 °C)
Standard version
Minimum set pressure and circulation pressure dependent on the flow 1)
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1)
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The characteristic curves apply to an output pressure pT =0 bar in the entire flow range.
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Version “U”
Minimum set pressure and circulation pressure dependent on the flow 1)
Inlet pressure dependent on the flow
Notice:
The characteristic curves were measured with external, depressurized pilot oil return.
Due to the internal pilot oil return, the inlet pressure increases by the output pressure present in port T.
Pilot flow
Type-examination tested safety valves
(Component series 5X, according to Pressure Equipment Directive 2014/68/EU)
Counter pressure in the discharge line
Basically, the valve should be operated without counter pressure in the discharge line, if possible. With counter pressure in the discharge line, the maximum flow possible is reduced. There is a relation between the maximum counter pressure pT in the discharge line and flow qV, which can be seen from the following characteristic curves. Characteristic curves for intermediate values of the response pressure which are not listed must be determined by means of interpolation.
With a flow approaching zero, the maximum counter pressure pT is in each case 10 % of the response pressure. With increasing flow, the maximum counter pressure pT is reduced.
Interpolation of intermediate values from the diagram
At the pT axis, mark 1/10 of the value of pA. Determine the next lower and the next higher characteristic curve for this point. The point marked at pT divides the section between lower and higher characteristic curve on the pT axis with a certain percentage. At the qVmax axis, divide the section between next lower and next higher characteristic curve in the same percentage as the section at the pT axis. From the zerocrossing on the qVmax axis determined in that way, draw a straight line to the value on the pT axis marked before. Mark the system flow to be secured at the qVmax axis. Read off the maximum counter pressure for this value using the line at the pT axis drawn before.
Determination of the maximum counter pressure
Example 1 (with already existing characteristic curve):
Flow of the system / accumulator to be secured:qVmax = [si]300 l/min[/si][imp]79.3 USgpm[/imp Safety valve set to: pA = [si]80 bar[/si][imp]1150 psi[/imp]. Read off the maximum counter pressure pT of approx. [si]12 bar[/si][imp]175 psi[/imp] from the diagram (see arrows, dashed line " ").
Example 2 (with interpolated characteristic curve):
Flow of the system / accumulator to be secured: qVmax = [si]300 l/min[/si][imp]79.3 USgpm[/imp Safety valve set to: pA = [si]80 bar[/si][imp]1150 psi[/imp] Value to be marked at the axis referred to as pT: 1/10 x [si]80 bar[/si][imp]1150 psi[/imp] = [si]8 bar[/si][imp]115 psi[/imp]. Read off the maximum counter pressure pT of approx. [si]1 bar[/si][imp]15 psi[/imp] from the diagram (see arrows, dashed/dotted line " ").
Size 10
Diagram for determining the maximum counter pressure pT in the discharge line at port T of the valve dependent on the flow qVmax for valves type DB(W)...E with different response pressures pA.Intermediate values may be determined by means of interpolation. Regarding the procedure for interpolation refer to "Interpolation of intermediate values from the diagram".
Size 20
Diagram for determining the maximum counter pressure pT in the discharge line at port T of the valve dependent on the flow qVmax for valves type DB(W)...E with different response pressures pA.Intermediate values may be determined by means of interpolation. Regarding the procedure for interpolation refer to "Interpolation of intermediate values from the diagram".
Size 30
Diagram for determining the maximum counter pressure pT in the discharge line at port T of the valve dependent on the flow qVmax for valves type DB(W)...E with different response pressures pA.Intermediate values may be determined by means of interpolation. Regarding the procedure for interpolation refer to "Interpolation of intermediate values from the diagram".
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pA
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Response pressure in bar
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pT
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Maximum counter pressure in the discharge line (port T) in bar
(sum of all possible counter pressures; also see AD2000 data sheet - A2)
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pT max
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10% x pA (with qV=0 l/min) according to Pressure Equipment Directive 2014/68/EU
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qV max
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Maximum flow in l/min
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