A bag-on-valve (BOV) spray is an aerosol can with the product in a welded bag and compressed air or nitrogen between the bag and the can wall; pressing the valve lets the propellant squeeze the bag, so it sprays at any angle, for as long as the valve is open, with no propellant in the product. A pre-compression pump is a non-pressurised finger pump that will not open until the spring reaches a set pressure, so every stroke is a full, even mist rather than a squirt. An ordinary fine-mist sprayer delivers 0.1–0.2 ml per actuation on 12.5–24 mm necks and is the stock, low-MOQ default from about 2,000 pieces; BOV and pre-compression are specialist components sourced at typical partner-factory ranges above that, with the gasket compound as the line that decides whether a pressurised pack leaks.
Three sprayers, one word
Consumers use "continuous spray" for any bottle that mists rather than squirts. In sourcing it means one of three assemblies, chosen by formula, angle of use and quantity.
| Format | How it works | Pressurised? | Spray character | Typical use |
|---|---|---|---|---|
| Fine-mist sprayer (stock) | Atmospheric-balance finger pump: piston, SUS304 spring, dip tube with glass ball, spray insert breaks the stream into droplets | No | One short mist per stroke; 0.1–0.2 ml per actuation; quality depends on viscosity | Toners, facial mists, perfume, styling water, body spray |
| Pre-compression pump | The piston compresses product against a spring-loaded valve; the valve opens only at a set pressure and closes below it, so the whole stroke exits at full pressure | No | Long, even, fine mist across the full stroke; no dribble at start or end | Facial mists, sunscreen mists, hair mists, fine-fragrance travel sprays |
| Bag-on-valve (BOV) | Product sealed in a multilayer bag welded to the valve; compressed air or nitrogen fills the space between bag and can | Yes (can pressure) | Continuous while the actuator is held; any angle including upside-down; no propellant contact with product | Sun sprays, thermal water, saline, wound care, aftersun, natural aerosols |
The stock fine-mist sprayer is the reference point because it is what most brands already buy: SUS304 spring, PP, LDPE or HDPE dip tube, aluminium crimp collar for perfume or plastic screw collar for general use. Full specifications are on airless, pump and sprayer specifications.
How bag-on-valve works
A BOV can is an ordinary tinplate or aluminium monobloc aerosol can, but the product never touches the can. The valve — actuator, stem, gasket, spring and mounting cup — is welded to a laminated bag; the bag is filled through the valve, and the space between bag and can wall is filled with compressed air or nitrogen. Pressing the actuator opens the valve and the gas squeezes the bag, so product exits as long as the actuator is held, at any angle, until the bag is nearly flat. The propellant never mixes with the formula, which is why BOV is used for sun sprays, thermal water, saline and anything sold as a natural or non-flammable aerosol.
The sourcing consequences follow from the can: a pressure-rated container with aerosol labelling and transport rules. Aluminium cans are 30–60% lighter than tinplate and corrosion-resistant but cost more and need a matching internal lacquer. And the gasket is the whole product: a gasket that swells 0.2 mm in the gas and formula environment is a leaking can, so the gasket compound is the single most important line in the specification — see row 7 of the formula × packaging compatibility matrix.
How a pre-compression pump works
A standard fine-mist sprayer opens its outlet as soon as the finger moves, so the first millimetre of travel gives a low-pressure dribble and the last a weak tail. A pre-compression pump adds a spring-loaded valve between the piston chamber and the nozzle: nothing leaves until chamber pressure reaches the set point, the whole charge then exits at that pressure through the swirl insert, and the valve closes before the stream can coarsen. The mist is fine and even from first millisecond to last, and the nozzle does not drip because the outlet is closed at rest.
It is a finger pump: no propellant, no pressure vessel, no aerosol labelling. It costs more than a stock sprayer, with more parts and tighter tolerances, and is stocked in fewer neck sizes and colours. It is the answer when the brief says "fine, continuous mist" but the brand does not want an aerosol.
Mist quality: what is measured
"Fine mist" is not a specification. Partner factories judge spray quality on measurable things, always with the brand's own bulk, because a sprayer that passes on water and streams on a formula has a viscosity or compatibility problem, not a nozzle problem.
| Check | Stock fine-mist sprayer | Pre-compression / BOV |
|---|---|---|
| Output per actuation | 0.1–0.2 ml; dosing error within 0.02 g | Pre-compression: set by pump size, weighed the same way; BOV: continuous, specified as g/s discharge rate (typical partner-factory range) |
| Mist pattern | Even mist, no droplets or streams, judged against a control | Same; BOV also checked at 45° and inverted |
| Priming | Counted strokes to first spray with the bulk | Pre-compression: counted strokes; BOV: none — sprays on first press |
| Service life | ≥1,500 continuous actuations; rated as n = Vtotal ÷ Vi × 1.2 | Pre-compression: ≥1,500; BOV: bag emptied to residual, residual weighed |
| Collar torque (screw / crimp) | 58.8–224 N by diameter, on a torque meter; overcap flip test with no cracking | Crimp on BOV mounting cup: crimp depth and diameter per valve supplier drawing |
| Leak | Vacuum chamber −0.06 MPa standard; −0.08 MPa 15 min, loss ≤0.5% for alcohol-based | BOV: hot-water bath leak test on every can as an aerosol; gasket swell checked in the 48°C / 30-day compatibility test |
| Compatibility | Actual bulk at 48°C for 30 days: spring, gasket, dip tube | Same, plus bag laminate and valve gasket against gas and formula |
The compatibility line is where fragrance and essential-oil mists fail: the pump body is usually fine, the seals are not. Above about 30% ethanol the gasket is PTFE-coated or solvent-grade; essential oils swell standard NBR/TPE, so silicone or fluoroelastomer is specified.
Sourcing: MOQ, tooling and lead time
All three are bought as stock components — sprayers and valves have many parts, so tooling is costly. What differs is how many sizes and finishes are on the shelf.
| Route | Indicative MOQ | Tooling | Factory-gate lead time |
|---|---|---|---|
| Stock bottle + stock fine-mist sprayer, screen-printed | About 2,000 pieces via partner factories | None — screen per colour only | 7–25 days bottle; +5–7 days print; sprayer from stock |
| Stock bottle + sprayed colour + stock sprayer | 2,000–5,000 pieces per shape | Spray line set-up per tone | 30–40 days |
| Pre-compression pump on a stock bottle | Typical partner-factory range above the stock-sprayer floor; fewer neck sizes and colours in stock | None for the pump; colour-matched actuators may carry a set-up | Pump lead time longer than a stock sprayer — confirm before committing a launch date |
| Bag-on-valve can, filled by a contract filler | Set by the filler's line minimum and the can supplier — typical partner-factory range, quoted per project | None for stock cans; printed cans carry a plate cost | Can, valve and bag are three suppliers plus the filler — plan on the longest of the three |
| Buffer rule | — | — | Quoted cycle × 1.3; +15 days across Chinese New Year |
A BOV programme is a filling decision as much as a packaging one — the bag is filled through the valve on a gassing line, so the contract filler is chosen alongside the can. A pre-compression pump usually fits a standard neck, so a brand can launch on a stock sprayer at 2,000 pieces and upgrade the actuator later. Bottle-side minimums are on the MOQ index, dates on the lead time index.
Which to choose
- Stock fine-mist sprayer for toners, facial mists, perfume and body spray when a per-stroke mist is acceptable.
- Pre-compression pump for a long, even, drip-free mist without an aerosol — sunscreen mists, hair mists, premium facial waters.
- Bag-on-valve when the product must spray at any angle, continuously, with no propellant in the formula, at a volume that justifies a gassing line.
Body sprays and deodorant mists use the same stock sprayer — 12.5–24 mm, 0.1–0.2 ml — on glass, PET (below ~30% alcohol) or alcohol-rated PETG; the format table is on deodorant packaging. Pressurised-pack rules by market are in the compliance guide, thresholds follow our QC standards, and the questions for a sprayer supplier are in how to evaluate a China packaging supplier.
Vella is a Guangzhou-based beauty packaging solutions provider — a sourcing partner working with vetted partner factories operating to ISO 22716 / GMP — and quotes the sprayer with the bottle, the gasket named against the formula and the mist tested on your bulk. Spray formats for a personal-care family are on haircare and bodycare packaging solutions.
Frequently asked
- How to Open a Pump Bottle That Won't Open: Lock-Down Pumps, Twist-to-Lock, Clip Locks — and What Brands Should Specify
- Essential Oil Spray and Roller Bottles: Amber Glass, Fine-Mist Sprayers, Roll-On Balls, Compatibility and MOQ
- Lotion Pump Dose (2 ml vs 4 ml) and the 1,500-Cycle Test: What to Specify
Launching a facial mist, sun spray or body spray?
Get the sprayer quoted with the bottle.
Send the formula, alcohol percentage, bottle size and quantity. Within 24 hours you get the stock sprayer, pre-compression and bag-on-valve routes with minimums, gasket spec and a mist test on your bulk.
Send a brief →