Aseptic filling valve (sterile-barrier valve unit for aseptic fillers)
Aseptic filling valves · the valve unit itself: how the stem is sealed against the atmosphere, how it is steam-sterilised in place, and its pressure, temperature and size ratings
An aseptic filling valve is the valve unit that opens and closes the flow of sterile product into a container on an aseptic filler, built so that the moving stem cannot carry micro-organisms from outside into the product path. This page is about the valve unit itself, the part a filler builder or a maintenance buyer orders. Ask three things first: what seals the stem against the atmosphere (a diaphragm, a bellows or a steam barrier), how the valve is sterilised in place and at what temperature and pressure, and which pressure, size and material ratings it carries.
Aseptic filling valves as valve units: diaphragm-sealed and bellows-sealed filling valves, steam-barrier fill valves for bags and drums, and double-plug isolation valves on the product feed of aseptic fillers, with their actuators and sterilisation ports. Complete aseptic filling machines are covered on the Aseptic filling machine page; complete aseptic cold-fill PET lines are covered on the Aseptic cold-fill PET beverage line page; counter-pressure and flowmeter filling valves for non-aseptic bottle and can fillers are covered on the Beverage filling nozzle assembly page. Container sterilisation and isolator air classes are outside this page.
CNFX editorial research · Sources checked October 12, 2026 · 6 sources
Choose how the valve stem is sealed from the atmosphere
The moving stem is where an aseptic valve differs from a hygienic one. Alfa Laval's Unique SSV Aseptic uses a one-piece diaphragm that hermetically seals the valve against intrusion from the atmosphere; the diaphragm is a sandwich of PTFE on the product side, EPDM and a reinforcing mesh, and it is mechanically supported by the valve in the open position to reduce wear. [2][1]
A bellows does the same job over a longer stroke. In Bernd Hansen's patent US5862840 for a sterile filling device, a bellows surrounds the moving block that carries the filling tap, sealed at one end to the block and at the other to the housing, and lengthens and shortens as the tap moves; the patent states that this embodiment removes the need to feed steam-barrier vapour during production, and that the bellows sits in a supporting sheath because the housing is pressurised during steam sterilisation. [3]
A steam barrier keeps live steam around the moving part instead. In David S. Smith Packaging's application EP1067052 for filling plastic bags, the fill valve has a path that keeps a steam barrier around the reciprocating product plunger through the whole cycle, with separate plungers opening the steam inlet and exhaust so the same valve sterilises its own product paths and the bag's gland and cap before each fill. [4]
Editorial note: ask the supplier which of these principles the valve uses, what the barrier is made of, how its integrity is checked between runs, and how it is replaced; a worn diaphragm or bellows breaks the barrier, so the replacement interval belongs in the quotation.
Give the supplier the filler type (bottle, cup, bag or drum), product (viscosity, particles, pH, temperature), nominal size and connections, product and sterilisation pressure and temperature, the stem-seal principle required, actuator type and air supply, position feedback, materials of product-wetted parts and seals, and the documents required.
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Check the sterilisation and operating ratings
Alfa Laval's leaflet for the Unique SSV Aseptic lists an operating temperature range of –10 °C to +140 °C with EPDM seals, a maximum sterilisation temperature of 150 °C at 380 kPa (3.8 bar) for less than one minute, a product pressure range of 0–800 kPa (0–8 bar) and actuator air of 500–700 kPa (5–7 bar). It adds that vacuum is not recommended in aseptic applications. [1]
In Hansen's sterile filling device, all parts are sterilised after cleaning with vapour at a pressure of up to 3 bar, fed into and discharged from a pressure-resistant housing so that every seal around the moving parts slides on a surface that has itself been sterilised. [3]
Fenco's patent US5193571 addresses what happens when one filling valve on a filler fails. Its isolation valve closes the branch to that filler valve with two plugs, one sliding inside the other; steam or another sterilising fluid flows through the chamber between the plugs, so the product feed conduit stays sterile while the filler valve is out of order. [5]
Editorial note: a short sterilisation peak, as in the 150 °C for less than one minute rating above, is not the same as a continuous steam-barrier duty; tell the supplier how long and how often the valve will see steam.
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Diaphragm, bellows, steam-barrier and double-plug valves side by side
Types differ in the barrier at the stem and in where the valve sits; the facts come from the cited documents, not from one valve maker's range.
Valve type
Barrier at the moving part
Source facts
Diaphragm-sealed seat valve
One-piece PTFE/EPDM diaphragm
0–8 bar; –10 to +140 °C; 150 °C / 3.8 bar under 1 min. [1]
Bellows-sealed filling tap
Bellows between moving block and housing
Steam sterilisation up to 3 bar; no barrier steam in production. [3]
Steam-barrier fill valve for bags
Live steam around the plunger
Same valve sterilises gland and cap before filling. [4]
Double-plug isolation valve
Sterilant-flushed chamber between two plugs
Keeps feed conduit sterile when a filler valve is out of order. [5]
Size, sterilisation and leak-tightness data for an aseptic filling valve quotation
Editorial calculation: Alfa Laval gives air consumption per stroke for NO and NC actuators on DN/OD 51–63.5 mm valves as 0.5 × air pressure in bar (litres of free air); at 6 bar that is 0.5 × 6 = 3 litres of free air per stroke for each valve. [1]
Field
What it means and published values
Ask the supplier for
Nominal Diameter (mm)
Bore of the valve. Alfa Laval lists DN/OD 25–101.6 mm and DIN DN 25–100 for the Unique SSV Aseptic. [1]
Size and connection standard.
Flow Rate (m³/h)
Alfa Laval gives Q = Kv × √Δp; its worked example is a 2.5-inch shut-off valve with Kv 111 passing 40 m³/h at about 0.13 bar drop. [1]
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
What makes a filling valve aseptic rather than hygienic?
A barrier at the moving stem keeps outside air and micro-organisms from the product path: Alfa Laval uses a hermetic PTFE/EPDM diaphragm, Hansen's patent a bellows, and EP1067052 a steam barrier. [2][3][4]
At what temperature is an aseptic valve sterilised?
Alfa Laval rates its aseptic single-seat valve for 150 °C at 3.8 bar for under one minute; Hansen's filling device uses vapour up to 3 bar. [1][3]
Can a filler keep running if one filling valve fails?
Fenco's patent describes a double-plug valve whose sterilant-flushed chamber isolates the failed filler valve while keeping the product feed sterile. [5]
Sources and what still needs a direct check
Sources checked 2026-10-12. Alfa Laval is a valve maker describing its own aseptic valve; Fenco, Bernd Hansen and David S. Smith Packaging are patent applicants describing their designs; Tech-Long is a filling-line maker describing its valves.
