Vacuum Pumps

Source: https://buythis.co.za/vacuum-pumps#ai

published: 2022-09-30 15:08:10
modified: 2024-07-24 11:42:37

What this page is

This is the Vacuum Pumps category page on Buythis, AM.CO.ZA's online shop. The live page is mostly a menu of links to router videos, signage routers, furniture routers, router bits, accessories, software and RouterCAM training. This Knowledge Base version explains the vacuum pumps AM.CO.ZA sells, using the AG-VACUUM product rows in the Buythis data (dated 2026-10-21), AM.CO.ZA's own articles and training notes on vacuum pumps, and the AM.CO.ZA videos listed below.

Why a CNC router needs a vacuum pump

A vacuum table holds sheet material flat and still while the router cuts, without clamps getting in the way of the tool. The pump sucks air out through the table so the sheet is pressed down by air pressure. It only works well when the table and spoilboard are sealed, because every air leak weakens the hold-down. AM.CO.ZA vacuum-table routers now ship with silicone instead of rubber cord for sealing, with a 6 mm supawood (MDF) spoilboard sealed and joined with silicone, and the table switches still used to choose zones (see Vacuum router: silicone and 6 mm supawood).

The two kinds of pump

AM.CO.ZA sells two kinds of vacuum pump, and they suit different work.

	Liquid ring vacuum pump	Regenerative air blower
How it works	A spinning impeller throws water to the outside of the pump body, forming a ring of water that leaves a strong vacuum in the centre	A spinning impeller moves a very large volume of air through the pump
Strength	Very strong vacuum (about 0.097 MPa on the 7.5 kW model), lower airflow	Very high airflow, weaker vacuum
Needs water	Yes, it runs from a water tank	No
Best for	Flat and thick sheets, MDF and supawood, most router work, as long as the table is well sealed	Thin, floppy sheets such as plastic under about 6 mm, through a porous or drilled spoilboard; it can also blow air
Noise	Loud at 7.5 kW (about 69 dB quoted)	Very loud at 7.5 kW, even with the silencer

AM.CO.ZA's sales advice is simple: for thin floppy plastic sheet, choose the regenerative blower; for everything else, choose the liquid ring pump. The full comparison is in Vacuum pump comparison: liquid ring versus regenerative blower and the short version in 7.5 kW liquid ring versus regenerative vacuum.

The range

Liquid ring pumps with a 260 litre water tank (complete sets)

AG-VACUUM/LR/30T: 220 V single-phase, 3 kW. Plugs into a normal wall socket; suits smaller routers such as the DIY router.
AG-VACUUM/LR/55T: 380 V three-phase, 5.5 kW.
AG-VACUUM/LR/75T: 380 V three-phase, 7.5 kW. AM.CO.ZA recommends it for 4 × 3 foot (40 × 30) and other large CNC routers.
AG-VACUUM/LR/110T: 380 V three-phase, 11 kW, for the largest tables.

Liquid ring pump bodies only (no tank)

AG-VACUUM/LR/30 (220 V, 3 kW), AG-VACUUM/LR/75 (380 V, 7.5 kW, maximum 16.5 A) and AG-VACUUM/LR/110 (380 V, 11 kW).
AG-VACUUM/LR/TANK: the water tank set with piping and fittings, for any liquid ring pump up to 11 kW. AM.CO.ZA assembles these tanks locally.

Regenerative air blowers (no water)

AG-VACUUM/RB: 380 V, 7.5 kW, 16 A, with silencer and safety relief valve. The Buythis short name gives 550 m³/h and 56 kPa; the am.im product name gives 320 m³/h and 55 kPa blowing or 43 kPa suction, so check the product page for the figure that matters to you.
AG-VACUUM/RB/2200: 220 V, 2.2 kW, made for flatbed oscillating blade cutting machines.
AG-VACUUM/RB/700: 220 V, 700 W, for smaller flatbed cutting machines.

Current prices are on each Buythis product page.

Setting up a liquid ring pump and tank

Choose the voltage you have. The 220 V pump uses a normal power cable and plugs into the wall. The 380 V pumps need a three-phase supply and should be wired by an electrician.
Place the pump next to the router or mount it on the wall, and connect the water tank to the pump with the supplied piping. A flexible hose on the water return into the tank is easier to line up and less likely to break than only the rigid factory hose.
Before first use, remove the cover and check that the motor turns freely.
Fill the tank. Keep the water level above the outlet valve and never below the motor.
Always open the tank valve before starting the pump, and close it when the pump is off so water cannot flow back into the system.
Connect the vacuum hose to the router table. Hoses come in 32 mm and 45 mm wire-reinforced lengths, and a vacuum gauge shows how well the table is holding.

On EasyRoute routers the pipes under a table of about 1300 × 2500 mm are laid out in four zones, A to D (see EasyRoute vacuum table pipe layout). The setup is shown in the videos below and in Water tank and liquid ring pump setup guide.

Looking after a liquid ring pump

Keep the water below 40 °C. Under vacuum water boils at a lower temperature, so the return water can come back steaming hot and the tank loses water as steam. Top up as needed; a second tank or other cooling helps in hot conditions (see Hot return water and flexible hose).
Change the water about every three months. Adding antifreeze or a soluble oil helps prevent corrosion.
Keep the whole system airtight with silicone and proper seals, which also stops debris from reaching the impeller.

Common problems

Weak hold-down: usually an air leak at the table, spoilboard or hoses. Reseal with silicone and check the gauge.
Clicking noise while running: often a damaged impeller. Replace it with a replacement impeller.
Water leaks: fix them quickly, using a plumber if needed, and check the shaft seal.
Burnt motor winding: take the motor to an electric motor rewinding specialist.

The full explanation is in Liquid ring vacuum pump: how it works, care and repair.