PET Bottle Filling Machine

A PET bottle filling machine fills and seals polyethylene terephthalate bottles. The difference from a glass filler is the bottle, not the valve: PET is light, deforms under pressure and cannot be buffered as a rigid container. A PET machine carries bottles by the neck ring, supports the body during counter-pressure filling and closes caps at low torque. A glass line uses a mechanical infeed and a heavier monoblock. The filling principle — level filling for still products, counter-pressure for carbonated ones — is the same on both.

Yes, if the pressure inside the bottle is balanced during the fill. The valve first pressurises the bottle with CO₂ to about the product pressure, typically 0.3–0.5 MPa, then fills against that equalised pressure, then vents in stages before capping. With no pressure difference across the wall, a 12–20 g bottle fills without bulging. Product is chilled to 2–6 °C to hold CO₂ in solution, and the bottle hangs by the neck with a support plate under the base. Venting is staged: releasing pressure in one step foams the product and short-fills the bottle.

The standard format set covers 330 ml, 500 ml and 750 ml bottles from 150 to 320 mm high and Φ52–84 mm in diameter; 1,000 ml and 1.5 L water formats are available on request. Necks run on changeable guides for 28 mm PCO 1881 and 1810, 30 mm and 38 mm finishes, with the cap elevator and chute set to match. Wall weight is not the limit as long as the neck guide matches the neck ring. Send a bottle drawing or sample and we will confirm format parts and conveyor settings before quoting.

Either works; it changes where the line starts, not what the filler does. If you blow on site, bottles leave the moulder warm and go straight onto an air conveyor into the rinser-filler-capper, with no packing, transport or storage. If you buy bottles, they arrive bagged or cartoned and enter through an unscrambler or loading table before rinsing. Buying keeps capital cost and floor space down but adds a per-bottle cost; blowing on site pays back at higher volumes and gives control over bottle design.

Standard PET softens above about 65–70 °C, so hot fill needs heat-set bottles with a crystallised neck rated for 85–92 °C. Product enters hot, the bottle is held and inverted so the liquid sterilises the cap and headspace, then passes through a cooling tunnel before labelling. Cold fill avoids the heat: the product is pasteurised or preserved upstream and filled into chemically sterilised bottles in a clean area at 4–20 °C. Cold fill is cheaper on bottles and energy but relies on preservatives or aseptic handling for shelf life.

Yes, and it is about handling, not the valve. A lighter bottle needs a neck guide that matches the neck ring exactly, lower air conveyor pressure so bottles do not ride up, gentler infeed transfers and reduced gripper force at the star wheels. rPET preforms vary more in colour and acetaldehyde than virgin resin, so blow settings and inspection limits need more tolerance and fill timing is trimmed to avoid foam on thin walls. Cap torque is set at the low end of the cap supplier range, because over-torqueing cracks a lightweight neck.

Output is heads multiplied by fill cycles per minute, then by 60. At 500 ml, a 4-head semi-automatic machine runs about 300–500 bottles per hour, a 6-head 500–700, an 8-head 700–900 and a 10-head 900–1,100; automatic monoblocks with 12, 18 or 24 heads run 1,000–5,000 BPH. Size the filler to the line, not the catalogue: if the labeller, shrink tunnel or packer cannot keep up, extra heads only add idle time. Plan on 80–85 % of rated speed over a shift, after changeovers and CIP.

Around the filler you need an air conveyor or unscrambler for empty bottles, a cap elevator and chute, a sleeve or self-adhesive labeller with a shrink tunnel, a date coder, accumulation conveyors and a packer. Carbonated products also need a CO₂ mixer and a chiller to hold the product at filling temperature; beer and juice may need a flash or tunnel pasteuriser upstream, and a buffer tank smooths supply from the blending area. We quote the filler alone or as a complete line, so modules can be added later.