Hydraulics & Pneumatics September 2022

HYDRAULICS specifications of the hydraulic system were as follows: Motor Power: 56 kW (75 HP) Calculated Power Required: 45 kW (60 HP) Pump Flow: 160 LPM Calculated Return Line Flow: 214 LPM Tank Volume: 750 litres Ambient Air Temperature: 40degC Max. Desired Oil Temperature: 60degC (Given an option I would like to try to restrict this to 55degC) Without going into the details of the hydraulic system & the components used, even if we assume the overall efficiency of hydraulic system as 70% The Heat Generation = 30% x motor power (KW) = 13.5 kW. From the heat dissipation table, we can see that for a tank of 750-litre capacity the calculation becomes something like this: Oil tank capacity = 750 liters Ambient air temp. = 40degC Max allowed oil temp. = 60degC T = 60- 40 = 20degC From the table Heat dissipation capacity = 1.82 kW Access heat production= 13.5 - 1.82 = 11.68 KW. A whopping 11.68 kW of heat is going be too late as the hydraulic system would have gone through irreversible damage much before that. At temperatures above 80degC the viscosity of the oil would have reduced drastically, making it susceptible to internal & external leakages. Furthermore, the additives added to the oil will irreversibly lose their properties. High hydraulic oil temperatures will progressively damage seals, internal moving parts and directly affect the power consumed, life & reliability of the equipment. Fit an oil cooler/heat exchanger or increase reservoir size? Therefore, we have two options. Either to increase the size of the tank or install an oil cooler. Even if we did manage to increase the oil tank size, the economics will rarely justify this. Not only on account of expense of building the tank, as also the increased oil fill cost, each time we replace the oil. We also must consider the cost of space occupied by such a large tank. Increasing the oil tank capacity therefore become unviable. In this particular example we would need to install an oil cooler with a heat dissipation capacity exceeding 14 KW & an oil flow handling capacity of at least 220 LPM. We help customers in finding the most cost-effective and efficient option available to: Reduce heat load, by tweaking their hydraulic system design Accurate estimation of heat dissipation Selecting of the right air-cooled oil cooler. www.aircooledoilcoolers.com 2080 2880 900 950 1000 1000 A A 825 40 75° 136 30 183 254 to be added to the oil. This is almost as good as having an electrical heater of 12 kW installed in the hydraulic system. As the equipment operates, the temperature will keep rising until the heat dissipation from the tank surface equals 13.5 kW. We would probably need a tank having a surface area of about 48 sq m, which depending on construction would amount to a tank or 4000 or 5000 litres capacity to be able to dissipate this much heat. Therefore, theoretically the oil temperature will keep rising until the heat 950 generated will equal the heat dissipated and we reach a state of equilibrium, only then will 150 the oil temperature stabilise. By then it would 100 200 600 600 120° 150 2808 1" Socket for hexplug 1069 116 10 889 889 116 20 2000 8 7 1 2 6 3 4 5 12 11 15 13 10 9 1029 200 B SECTION A-A SCALE 1 : 15 15 40 40 4 DETAIL B SCALE 1 : 5 NOTES: TOP PLATE: 950x1000x4 (4 SET) • 900x1000x4 (2 SET). (TO BE BOLTED OVER THE • TANK TOP) DO NOT USE JOINTS IN SHEET FOR TANK • MANUFACTURING ALSO USE SHEET SIZE AS SPECIFIED BY US & • TRY TO PREVENT RUSTING. REVISIONS REV. DESCRIPTION DATE DONEBY APPROVED A REMOVED SURFACE TREATMENT 08-Aug-20 08-Aug-20 AMIT ITEMNO. DESCRIPTION QTY. WEIGHT 1 FRONT SHEET 1 324.79 2 SIDE SHEET 2 81.45 3 DRAINPLUG 2 0.18 4 BAFFLEPLATE 2 28.08 5 GUSSET 6 3.79 6 CENTRE LEG 1 38.68 7 L40x40x5 2 5.97 8 L40x40x5 2 8.29 9 L45x45x5 2 9.19 10 L45x45x5 2 6.54 11 L45x45x5 2 6.46 12 L45x45x5 1 3.05 13 L45x45x5 1 2.90 14 L45x45x5 1 2.99 15 L45x45x5 2 2.78 WEIGHT: A 1:20 Projection: ACE AUTOMATION ENGINEERS C-164,MAYAPURI INDUSTRIALAREA,PHASE-II,DELHI- 110064 PH.011-28114501,011-28114502, FAX011-28114503 AMIT Drawndate: Title: DrawingNo.: MATERIAL: SHEET SIZE: SHEET Ref.Drg.no. HIMANSHU 19-Jul-19 ±6 UPTO TOL. ±1 ±2 ±3 ±4 ±5 10000 500 6000 1000 2000 3500 Surface treatment: Scale: 1OF1 A3 MILD STEEL 693.02Kg. (Apprx.) Checkedby: Drawnby: Apprdby: S-1101581 A ---- Rev.No. A OIL TANK 4000 LTRS. ---- ---- Alldimensionsare inmilimeter (mm). Open Tolerance REMOVE SHARP EDGES FABRICATION TOL. UPTO MACHINING 6 30 100 300 1000 2000 ±0.2 ±0.8 ±0.5 ±0.3 ±1.2 ±0.1 Level L0 26 HYDRAULICS & PNEUMATICS September 2022 www.hpmag.co.uk BELOW Figure 2: Dimensional drawing of a 4000 litre hydraulic reservoir. LEFT: Oil cooler/heat exchanger.