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Integrated bypass
developed by
Hydac SA
Time scheduleTime schedule
• What is an integrated bypass
• Why this development
• How do the IBP & IBT valves function
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Integrated bypass
What is an integrated bypass
What is an integrated bypass
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Integrated bypass
Hydac’s integrated bypass is a standard bypass mounted inside a special radiator expressly designed for this.
A bypass is necessary to limit the inlet pressure and to help the rig’s startup with cold liquid.
Why ?...only advantages !Why ?...only advantages !
TO REDUCE :
• Problems
• Space
• Cost
With easy maintenance
>>
NEW
and innovative
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Integrated bypass
Even betterthan the standard external bypass
Even betterthan the standard external bypass
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oil flow [l/min]
pres
sure
dro
p [b
ar] a
t 430
mm
2/s
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Integrated bypass
Standard radiatorStandard radiator with external bypass 3 bar
Radiator with IBP3
Radiator with IBP3
Radiator with integrated bypass
IBP operationPressure drop dependingIBP operationPressure drop depending
The IBP valve is closed if the pressure drop in the element is lower than the action set valve.
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Integrated bypass
When the bypass is open the liquid flows through the element and the bypass channel.
The IBP valve opens if the pressure drop in the element goes over the action set valve.
Pre
ssu
re d
rop
Oil flow
Clo
se v
alv
e
Valv
e o
pen
action values set
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0 20 40 60 80 100 120 140 160 180 200 220 240 260Oil flow [l/min]
Pre
ssur
e dr
op a
t 30
mm
2/s
[bar
]
IBP2
IBP3
IBP actionValve & channel pressure dropIBP actionValve & channel pressure drop
Available valves :
• 2 bar >> IBP2
• 3 bar >> IBP3
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Integrated bypass
p opening valve action p with valve compleatly open
Tolerance ± 5 %
This holds into account the spring variability action and the channel dimensions.
IBP estimatedElement pressure dropIBP estimatedElement pressure drop
Combine the curves to obtain the element pressure drop.
To do this it is only necessary to translate the valve pressure drop curve parallel to the oil flow axis until it is tangent to the pressure drop matrix.
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Oil f low [l/min]
Pre
ssur
e dr
op [b
ar]
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Integrated bypass
IBT operationTemperature dependingIBT operationTemperature depending
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Integrated bypass
The IBT valve is closed if the inlet oil temperature is above that of the action set valve (hot liquid).
To have the maximal power heat exchange.
The IBT valve is open if the inlet oil temperature is below that of the action set valve (cold liquid).
To reduce the pressure drop consequent to the viscosity increase.
IBT action Temperature settingsIBT action Temperature settings
Available with closing temperatures of :
45 °C >> IBT45
50 °C >> IBT50
60 °C >> IBT60
This means that, for an IBT45 the bypass is open until 45 °C and after this it will start to close. It takes 5°C to close the valve completely (IBT45 is completely closed at 50 °C and IBT60 at 65°C)
The tolerance is 3 °C
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Integrated bypass
Now we are checking for the pressure drop on the elements with open bypass (low
temperature).
the valve action is the same of an IBP valve (it opens if the pressure drop in the element goes over the action set valve).
IBT operationPressure drop dependingIBT operationPressure drop depending
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0 50 100 150 200 250 300Oil flow [l/min]
Pre
ssur
e dr
op a
t 30
mm
2/s
[bar
]
Available valves :
> 2 bar (like an IBP2)
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Integrated bypass
When the IBT valve is closed because the temperature is above the action set valve,
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Oil f low [l/min]
Pre
ssur
e dr
op [b
ar]
IBT estimationElement pressure dropIBT estimationElement pressure drop
Combine the curves to obtain the same element pressure drop as for the IBP element.
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Integrated bypass
Take care of the viscosity of the liquid (declared values at 30 mm2/s)
