AKPV Hazardous Area Cooler Equipment for Hazardous Areas Cooler bellhousing VDMAcompatible, resistant to pressure peaks. Cooler bellhousings are well established in the field of oil hydraulics. The company JBJ Techniques are pleased to present a range of product that goes far beyond a “facelift” and offers users substantial advantages. Developed from the KPV product range first manufactured by our principles R+LHydraulics, JBJ, along with R+L are the first to bring cooler bellhousings with prismatic standard cooling elements which can be selected from catalogue information. The new series name is “AKPV” which has been specifically manufactured to satisfy ATEX Directive 2014/34/EU, Ex h IIC c Ts-20°C…T140°C Gb Ux and harmonised standards:- BS EN 1127-1, BS EN 60079-0, BS EN ISO 80079-36, BS EN ISO 80079-37, BS EN 14986 ISO 14694. The first cooler bellhousings on the market were usually fitted with finned tubes, which act as heat exchangers. However, due to the poor thermal design were only deemed suitable for leakage cooling. The high efficiency of the prismatic cooling element gives real possibilities for increased performance and also lends itself to full flow cooling as per the attached diagrams. Care must be taken when applied to low pressure return lines as often the operation of the system will generate pressure spikes which cannot generally be detected with conventional pressure measuring gauges. To combat this, R+L have extensively dynamically fatigue tested the prismatic element for over a 6 million stress cycles from 0 – 16 bar at a constant frequency of 2 Hz.As a rule, 1 x 10 stress cycles will be considered sufficient. However, since the number of pressure peaks per time period can be 6 extremely variable in isolated cases, it is difficult to determine which service life 10 stress cycles 6 correspond to. Considering this, testing has been extended to 3.5 x 10 stress cycles. In all cases, test results have been satisfactory. In addition to this, each single heat exchanger has been tested at 40 bar during production, this is equivalent to the highest authorised static pressure for cooling elements. Also, great attention has been paid to protecting the cooling element against external damage by embedding it within a sturdy housing on theAKPV cooler. CoolingCapacity It is generally accepted that, in the absence of an external source of thermal input, then heat loss of 30 - 40% of the equipment installed power will be required given that themotors and pumps are of average efficiency.Aproportion of this heat is generally radiated by the individual components within the system, especially the tank, and so the cooler bellhousing will be required to maintain oil temperature at the required level. This can also be effected by the system application, for example in machine tools or inmobile operational cases, an average cooling power of 20 – 30%of installed power is required. As shown in the cooling power of the AKPV fulfils this requirement to the full. The values shown apply to a Δt of 40K and to the optimum flow of oil. In the case of figure 1 lower or intermittent oil flow a separate cooling systemmay be necessary, this can easily be achieved with theAKPV cooler. The interdependence between the cooling power and the oil flow is shown within . The specific values per 1K Δt allow a simple conversion of the actual cooling figure 2 power by multiplication of the respective Δt. Compatibility to VDMA24561 Another important feature of the KPV/AKPV is the ability to retrofit into existing systems should existing installations change and the need for cooling be required to fit the new requirements, the cooler bellhousing can be replaced within the same size envelope, either a rigid bellhousing or a bellhousing fitted with damping flange, which means that pump andmotor position will not be altered and even pipework should remain the same. KPV coolers can be supplied either as a rigid version or as a version with integrated noise damping flange. AKPV cooler bellhousings are only available in rigid format. Correction factor for the ∆p-values depending on other viscosity in cSt cSt 15 22 32 46 68 100 150 220 460 k 0.64 0.73 1 1.28 1.62 2.65 3.9 6.9 17.1 0 10 20 30 40 Input 1 bar Dynamic fatigue strain tests with cooling elements for the KPV series coolers 6 at 16 bar with 1 x 10 stress cycles and f = 2 Hz 0 1 2 3 4 5 01 5 sec Fig. 1 Specific cooling power P/t of the series KPV depending on oil flow Q and temperature difference Δt = 1K (oil inlet to air inlet). 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 KPV350 KPV300 KPV250 KPV200 Oil flow [l/min] Specific cooling capacity P/Dt (W/K) 0 10 20 30 40 50 60 70 80 KPV200 KPV250 KPV300 0,5 1,0 1,5 2,0 2,5 3,0 Pressure drop p [bar] Oil flow Q [l/min] KPV350 0 0 10 20 30 40 50 60 70 80 Fig. 2 Pressure drop of cooler matrix at the oil viscosity of 32 cSt.
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