Liquid jet vacuum pumps
Transcription
Liquid jet vacuum pumps
Liquid jet vacuum pumps of porcelain Applications Example 0.6 kg/h of air has to be continuously exhausted out of a plant. The suction pressure amounts to 100 mbar abs. A motive liquid pressure of 5 bar g is available. The motive water has a temperature of 20 °C. Parameters to be found : Size of pump and motive water consumption. Solution : From diagram fig. 11, for a suction pressure of 100 mbar and a motive water pressure of 5 bar g, pump size 3 with a mass suction flow of 0.67 kg/h is closest to the required suction volume. From diagram fig. 12, for a motive water pressure of 5 bar g and a suction pressure of 100 mbar a motive water consumption of 5.5 m³/h for the chosen size 3 can be found. Suction pressure p 0 in mbar abs. (for water at 20 °C) Size Pressure indications in bar = bar g Fig. 12 Size GEA Wiegand GmbH 76275 Ettlingen · Germany · Tel.: +49 7243 705-0 www.gea-wiegand.com Fax: +49 7243 705-330 · E-mail: [email protected] Motive water pressure p1 in bar Pressure indications in bar = bar g p0 = Suction pressure in mbar abs. 39 fvp3 09 Diagram fig. 11 gives the mass suction flow in kg/h of air in relation to the suction pressure at various operating water pressures for 4 pump sizes. The curves are based on an operating water temperature of 20 °C. The motive liquid consumption or the motive liquid flow (circulating water operation) can be taken from diagram fig. 12. p1 = Motive water pressure Mass suction flow Ø0 in kg/h (air) Performance chart of vacuum pumps Fig. 11 Motive water consumption (Motive water flow) å1 in m3/h Liquid jet vacuum pumps of porcelain are used in laboratories and in pilot and production plants. They are used for evacuating syphon lines on acid plants, for producing vacuum, for deaerating apparatus in which solvent vapours are produced and for producing negative pressures in Nutsch filters, etc. Jet pumps of porcelain are encased in a protective armour of cast iron. These pumps are, therefore, well protected against mechanical and chemical aggression. They are reliable and maintenance-free; the capital cost is low. Liquid jet vacuum pumps of porcelain Performance chart for pre-evacuators Evacuation time Diagram fig. 13 gives the time in minutes a liquid jet vacuum pump size 3 needs to evacuate a vessel volume of 1 m³ to a defined suction pressure. The selection of other sizes is achieved by the following conversion formula: a liquid jet vacuum pump size 3 requires 2 x 12 = 24 minutes. However, as only 15 minutes are available the above formula is used to calculate the factor for the larger size of pump required: According to the table factor 2 corresponding to pump size 4 is closest to the calculated value. Pump size 4 is therefore selected. The motive liquid consumption is influenced by the suction pressure p 0 . This is established by means of the curves in fig. 12. Fig. 13 F Factor for the selection of the pump size p1 = Motive water pressure tspec.Specific evacuation time in min/m³ (from diagram fig. 13) tevac. Expected evacuation time in minutes Volume of vessel to be evacuated in m³ Size Factor F 1 2 3 4 0.33 0.5 1 2 Suction pressure in mbar abs. V Example A vessel of 2 m³ is to be evacuated to 400 mbar in 15 minutes. The water pressure is 3 bar. Parameters to be found: Size of the pump Solution: From diagram fig. 13, for 400 mbar and 3 bar, a time of 12 min/m³ is found. For the evacuation of a vessel volume of 2 m³, Specific evacuation time t spec. in min/m3 vessel volume for size 3 Pressure indications in bar = bar g Fig. 14 Connections, dimensions and weights Größe Operating water connection A 1 2 3 4 32 32 40 50 Suction connection B 25 25 25 32 Pressure connection C 32 32 50 65 Dimensions in mm a 290 290 390 500 b 60 60 80 100 c 230 230 310 400 d 90 90 100 110 10 11 18 22 Weight in kg Standard construction: Metal and special constructions: Pump body: porcelain with cast iron armour; Motive nozzle: porcelain Connections according to DIN PN 10 Please see “Liquid jet vacuum pumps with threaded connections”, o | fvp 1, and “Liquid jet vacuum pumps with flanged connections”, o | fvp 2. fvp3 09 For inquiries please use our questionnaire. 40 GEA Wiegand GmbH 76275 Ettlingen · Germany · Tel.: +49 7243 705-0 www.gea-wiegand.com Fax: +49 7243 705-330 · E-mail: [email protected]