Manual for the Design of Pipe Systems and Pumps - GEA ...

More documents

Recommendations

Info

6.3 Modification 6.3.1 Throttling 6.3.2 Changing the speed In the previous example the pump design took place in four steps. In practice, however, pumps are used at different operating points. These may be pumping of viscous media, temperature changes or systems with integratation of pressurised tanks. Changes in the flow head of a system H A (throttling) are realised in practice by increasing or reducing the resistance on the delivery side of the pump, e.g. by installing a throttling valve. In this case the operating point is always located on the intersection of the plant characterstic curve with the pump characteristic curve. H Drosselung Throttling Fig. 23 - Throttling B 1 gedrosseltes Throttled valve Ventil B 2 Changing the speed (n) causes a change of the operating point and thus of the flow rate (Q) and the flow head (H). For this purpose a frequency converter or a pole changing motor is needed. In spite of the high purchase costs for a frequency converter, its use is in view of the operating costs the clearly more favourable alternative to the throttling process with a throttling valve. Speed control is used, if different operating points shall be achieved, e.g. for product and cleaning liquid. H H1 H 2 Drehzahländerung Changing the speed Fig. 24 - Changing the speed B 2 28 GEA Tuchenhagen B 1 D 2 Pump characteristic geöffnetes Opened valve Ventil B 3 Plant characteristic D 1 Q 2 Q 1 Q Q n2 Q2 = x Q1 n1 n2 n1 2 H 2 = x H 1 n2 n1 3 P 2 = x P 1
6.3.3 Reducing the impeller size 6.3.4 Operation in parallel 6.3.5 Operation in series Tuchenhagen offers for each pump different impeller sizes. It may happen that the best efficiency point of the impeller is located between two characteristic curves. The impeller will then be turned to size in order to obtain the required diameter. This is both the most simple and favourable method. H H 1 H 2 Reducing Impeller the reduced impeller size picture 4 Fig. 25 - Reducing the impeller size Two pumps can be operated in parallel, if the desired operating point cannot be reached with only one pump. In such a case the flow of the two pumps are added while the flow head remains unchanged. Q 1 Q 2 Fig. 26 - Operation in parallel B 2 If the required flow head cannot be achieved by one pump only, two pumps are connected in series. Thus the flow head is doubled at constant flow rate. P 1 P2 Fig. 27 - Operation in series P = P 1 + P 2 Q = constant 29 GEA Tuchenhagen B 1 D 2 D 1 Q 2 Q 1 Q Q = Q 1 + Q 2 P = constant D 1 D 2 2 Q1 Q2 ≈ ≈ H 1 H 2
Page 1 and 2: Manual for the Design of Pipe Syste
Page 3 and 4: Table of Contents Page 1 General Pr
Page 5 and 6: Preface Archimedes - the ingenious
Page 7 and 8: 2 Introduction 2.1 Pipe systems 2.2
Page 9 and 10: 2.5 Applications 2.6 Capacity range
Page 11 and 12: 2.11 Self-priming centrifugal pumps
Page 13 and 14: 3.6 Fluid behaviour The flow curve
Page 15 and 16: 4.4 Friction losses 4.5 Reynolds nu
Page 17 and 18: 5.3 Suction pipe 5.4 Delivery pipe
Page 19 and 20: 5.7 Cavitation Fig. 14 - Pumping sy
Page 21 and 22: 5.9 Flow rate 5.10 Flow head 5.11 P
Page 23 and 24: Example 1 - Negative supply Hd,geo
Page 25 and 26: 6.1.2 Explanations 6.1.3 Calculatio
Page 27: Step 3 Step 4 The NPSH/Q Diagram (F
Page 31 and 32: 6.4.2 Calculation of correction fac
Page 33 and 34: 7.3 Example Product data • Medium
Page 35 and 36: 7.5 Result 7. In diagram 4 (Fig. 32
Page 37 and 38: 8.2 Pressure drops of fittings in m
Page 39 and 40: 8.4 Vapour pressure table for water
Page 41 and 42: DN 40 200 Hv [m/100 m] 100 50 30 20
Page 43 and 44: DN 100 100 Hv [m/100 m] 50 30 20 10
Page 45 and 46: 8.6 SI - Units Legal units (Abstrac
Page 47 and 48: 8.8 Viscosity table (guideline valu
Page 49 and 50: 8.9 Mechanical seals (recommendatio
Page 51 and 52: 8.10 Pump data sheet Pumping medium
Page 53 and 54: Notes 53 GEA Tuchenhagen
Page 55 and 56: 55 GEA Tuchenhagen

Manual for the Design of Pipe Systems and Pumps - GEA ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?