Packaged vacuum pump system (skid unit with separator, heat exchanger and booster stage)

01

Choose the seal-liquid loop on a liquid ring package

Atlas Copco describes three ways to package a liquid ring pump. A once-through power pack is the pump with motor, drive and base frame, sending the liquid and gas mixture to drain; Atlas Copco says it suits sites with an ample supply of seal liquid that can be discharged. In partial recirculation a discharge separator recovers service liquid and mixes it with fresh seal liquid to hold a constant pump temperature, which Atlas Copco says "offers typical water savings of 50% compared to once-through operation". Total recovery is a closed loop with a heat exchanger between the separator and the pump, and Atlas Copco states it "offers typical water savings of up to 95%" against once-through. [1]

Writing in Pumps & Systems, Busch's Benjamin Cameron ties the choice to the gas stream: once-through operation continuously flushes the pump where particulate carryover is expected, while full recovery suits cleaner gases and plants where continuous disposal of contaminated water or condensed solvents is unwanted. He adds that savings from partial recovery depend on the vacuum level, the fresh-water temperature and the heat added to the seal liquid, and that a water-cooled heat exchanger raises the plant's cooling-water demand while an air-cooled one raises power consumption. For rough-vacuum duty or large seal flows, a recirculation pump may be needed to overcome pipework losses from the separator back to the pump. [2]

Foryou's 2BW closed-loop unit shows the full-recovery layout: gas leaves the pump with some working liquid into a vapour-liquid separator; the gas then passes a spiral-wound heat exchanger where condensable vapours condense into a recovery tank, and non-condensable gas exits the system; the separated liquid is cooled in the heat exchanger and returns to the pump. Foryou says the pumped solvent can serve as the working liquid, and supplies the unit with pump, separator, heat exchanger, frame and internal piping as one set. [3]

Editorial calculation: at Atlas Copco's stated savings, a package that would draw 100 units of fresh seal liquid once-through would draw about 50 units with partial recirculation and as little as 5 units with total recovery, before the cooling duty moved to the heat exchanger is counted. [1]

Give the supplier the gas and vapour load, any solvents or particulates, the operating pressure, the seal liquid you can supply and its temperature, cooling water or ambient air available for the heat exchanger, and whether condensed solvent must be recovered.

02

Stage a booster pump above the backing pump

Souz's JZPS Roots–liquid ring systems put a Roots pump as the main pump on a liquid ring backing pump. Its table lists, for each pairing, the pumping capacity, the maximum inlet pressure for the set and the total installed power: the JZJ2S30-1 (ZJ30 on a 2SK-1.5) gives 30 L/s with a 12,000 Pa maximum inlet pressure and 4.75 kW; the JZJ2S600-2A (ZJ600 on a 2SK-12) gives 600 L/s with 4,000 Pa and 27.5 kW; the JZJ2S600-2B (ZJ600 on a larger 2SK-20) gives the same 600 L/s with 7,000 Pa and 42.5 kW. [4]

Editorial calculation: in the two 600 L/s Souz sets, moving to the larger backing pump raises the listed maximum inlet pressure from 4,000 to 7,000 Pa and the installed power from 27.5 to 42.5 kW, an increase of about 55%. 600 L/s × 3.6 = 2,160 m³/h. [4] Editorial note: the maximum inlet pressure bounds where the set works as a pair; ask how the booster is started and protected above that pressure (bypass, delayed start or variable speed).

Baosi lists a dry system pairing: the GSD160/1080D, a 1,080 m³/h system with a GSD160 dry screw backing pump, 0.1 Pa (1 × 10⁻³ mbar) ultimate pressure, motor power of 5.5 + 3.7 kW, 380 or 400 V three-phase supply, VG100 inlet and KF40 outlet, water cooling, 72 dB(A) and 495/520 kg. Baosi describes nitrogen purging to keep process gas out of the gearbox, automatic chamber cleaning at shutdown, and remote control through I/O and RS485 (Modbus). [5] Editorial calculation: 1,080 m³/h ÷ 3.6 = 300 L/s, and installed motor power totals 9.2 kW.

03

Once-through, total-recovery, Roots-boosted and dry-screw packages

Ask each supplier to draw the skid boundary: which valves, instruments, separators, heat exchangers and control panels are included, and which connections the plant must supply.

04

Backing pump, booster, separator and recovery tank on the skid

05

Package pumping speed at the inlet, not the bare pump's

06

Send the gas, loop and skid data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Process: [gas and vapour load; solvents; particulates; operating pressure]
Speed: [m³/h at operating pressure]
Loop: [once-through, partial or total recovery; seal liquid; cooling]
Stages: [booster type; backing pump; maximum inlet pressure]
Skid: [separator; heat exchanger; receiver; valves and instruments included]
Site: [voltage; frequency; cooling water; area classification]
Controls: [local panel; remote signals]

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