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Cooling requirements and cooling effect
Input data for hydraulic oil Density ρ = approx. 0,89 kg/dm By measuring the speed at which the oil temperature in thesystem rises, the required cooling effect can be estimated.
3 Specific heatC
P = approx. 2,08 kJ/kg C Basic formulae and calculations Required cooling effect as indicated by
the measured temperature rise of the oil= P (kW)System volume*= V (liter)Density of the oil to be cooled= Calculation example ρ (kg/dm Assume the following values:System volym= 250 lRecommended oil temperature= 55
3 )Specific heat of the oil= C CAmbient air temperature= 25
p (kJ/kg C)Initial temperature of the oil= T CInitial temperature of the oil= 25
1 ( C)Final temperature of the oil at end
of measurement period= T CPump flow= 70 l/minMeasurement for 30 min shows that the oil temperaturrises 45
2 ( C)Measurement period= t (min)Specific cooling effect **=Q
itd (kW/ C)Recommended oil temperature= T C.Required coolingeffect (P) =Hence Qitd Q
3 ( C)Ambient air temperature= T
4 ( C) 250
x 0,89
x 2,08
x (45-25)30
*The tank volume may be used if the total volume is not estimated to besignificantly larger. ** Cooling effect per 1 x 60
C in difference between oil and ambient airtemperature. itd =For low-pressure systems and an oil flow of 70l/min, theCP-STD-640 cooling effect diagram states: Q C5,14 Calculation formula:The estimated value of the cooling effect is used tocalculate the specific cooling effect Q 55-25 = 0,17 kW/
x ρ
x C
x (T -T )= kW P = t
p 2 1 x 60V
itd = 0,18 kW/ C We thus recommend the CP-STD-640 cooling pack
itd which indicates thecooling effect that the cooling pack must achieve per C indifference between the recommended oil temperature andthe ambient air temperature.With the aid of the Q
itd value and the pump flow (l/min),an appropriate cooling pack may be chosen from thecooling effect diagram.
Calculation formula: Q
1 itd =P = kW/ C
= 5,14 kW T
3 - T
4 Optional mounting Connecting to the system Technical data
Thanks to the sturdy design, the coolercan be mounted either horizontally orvertically. The simplest attachment
method is to use the flanges which, inthe standard design, are located in linewith the front surface of the cooler.
This is particularly advantageous forwall mounting. Connection to the system should be bya hose which is under no stress, toavoid damage to the cooler. If there are
pressure shocks in the system, thecooling pack should be mounted in aseparate cooling circuit. In such cases it
is appropriate to use the CD STDcooling pack since the pressure in thecirculation circuit is low. Operating voltage: 12 or 24 V DC,230 V single phase and 230/400 Vthree phase
Frequency: 50/60 HzProtection: IP44, IP54Insulation class: B, F