Lotion Pump Bottles: Pump Type, Dose and Neck Fit

Lotion Pump, Fine Mist Sprayer or Pressed Dropper: Which Output the Formula Needs

Three dispensing systems are routinely confused with one another because all three are pressed by hand and all three sit on a glass neck. What separates them is the physics of how the product leaves the pack, and that difference decides which of the three a given formula can use at all.

A lotion pump is a positive-displacement device. Each full stroke pushes a fixed volume out of a metering chamber, and the product leaves as a short ribbon, a ribbon-coil or a soft deposit. Because the pressure it generates is high and its outlet is wide, it handles creams, lotions, gels, thicker serums and products carrying mild particles. This is the system for a hand lotion, a body cream, a cleanser, a sunscreen or a foundation, and among the three it is the one that reliably dispenses a product thick enough to hold its shape when it lands.

A fine mist sprayer is an atomising device. The product is forced through a small orifice and breaks into droplets, which requires a low-viscosity, freely flowing liquid: a toner, an alcohol-based mist, a facial or body spray. Put a lotion into a mist sprayer and it either will not draw at all, or arrives as a jet of coarse droplets instead of a mist, with the orifice partly blocked by the following stroke. The choice between pump and sprayer is therefore settled by viscosity before any commercial question is asked, and the mist route is worked through on the spray bottle pages rather than here.

A pressed dropper sits between the two. A button or a squeeze action delivers a small, drop-wise dose or a very short stream, typically for a serum, an oil or a treatment where the consumer wants a few drops rather than a measured ribbon. Its delivered volume is smaller and less precisely metered than a pump’s, and it is the usual answer when the fill is expensive, the dose is counted in drops and the pack is small. Where the product is a thin oil and no fixed metered output is claimed, a pressed dropper is often the cheaper route; where the brand claim depends on “one press, one dose”, a lotion pump is the honest choice.

The practical test is a sentence about the product rather than about the pack. “It is a 5,000 cPs lotion that a consumer applies one-handed and expects to use about half a millilitre per application” selects a lotion pump and a dose grade on its own. “It is a sixty per cent alcohol toner applied as a mist” selects a sprayer. “It is a two millilitre dose of a facial oil” selects a pressed dropper or a very small pump. Writing that sentence before contacting anyone saves a sampling round.

What Can Be Customised on a Glass Pump Bottle

Customisation divides into two halves with very different cost consequences, and buyers who treat them as one conversation usually end up paying for tooling they did not need.

The bottle side carries the body: capacity, diameter and height, shoulder shape, panel or embossing, the colour or transparency of the glass, and the neck finish. The glass bottle range shows how those choices behave in practice, and the single most important one for a pump is the finish, because the pump has to match the neck rather than the neck being reshaped around a chosen pump.

The pump side carries the engine: the type, the output per stroke, the material set of the wetted parts, the dip tube bore and length, and the closure. Above that sits the visible hardware. The actuator may be ribbed, smooth, domed or shaped. The collar or skirt may be plain plastic, a covered shell in a metal finish, or matched to the bottle. An overcap may be a simple dust cover or may double as the transport lock. Actuator colour and collar finish are the cheapest forms of customisation and are usually achieved with existing tooling. A new actuator geometry, a new collar profile or a non-standard neck is a moulded part, and it brings tooling, development time and a minimum quantity with it.

A useful discipline at this stage is to decide which side of the line each requirement falls on. “A 100 ml amber bottle with a 24-410 neck, a 0.5 ml pump and a matte black actuator” is a request that can be met from standard parts. “A pump that fits our existing branded bottle, which has a 26 mm neck of our own design” is a moulding project on both the bottle and the pump collar and should be priced as one. Treating the second request as though it were the first is the most common cause of a schedule that slips after the artwork is approved.

Dose Output Grades and How a Single Dispense Is Controlled

Pumps are catalogued by output per stroke, in millilitres, and the grades are standardised broadly enough that a short list covers most of the market: 0.2, 0.4, 0.5, 1.0, 1.5, 2.0, 3.0 and 4.0 ml per stroke, with variations between families and suppliers. The figure is a property of the engine, not of the actuator, and that is the point most often missed in a briefing.

Inside the pump, the dose is set by the volume swept by the piston in its cylinder: the bore of the chamber multiplied by the length of the stroke, together with the timing of the inlet and outlet valves. Nothing a buyer can see from outside changes it. A longer actuator with a larger button looks as though it dispenses more; it does not. Changing the dose means changing the pump engine to a different grade, and a grade change normally brings a different chamber, a different spring load and a different down-stroke force with it.

Down-stroke force deserves more attention than it usually gets. A 0.2 ml engine on a small serum bottle is light to press. A 3.0 or 4.0 ml engine, with its larger chamber and longer travel, needs a firmer press, and the bottle has to be held steady while it is pressed. A large-dose pump on a tall, narrow bottle is awkward to use and can be tipped by the force of the stroke, so the pump and the body should be chosen together, with stroke force and bottle stability in the same conversation.

Two further conventions belong in the specification. The first is priming: a new pump arrives dry, and the chamber, the valves and the dip tube must fill before any product leaves the nozzle. The strokes needed to reach the first product are priming strokes, not doses, so a pack quoted as holding two hundred doses delivers about that number of usable strokes only once priming has been accounted for separately. The second is that a dose is a volumetric figure, not a weight. A 1.0 ml stroke of a dense cream weighs well over a gram, so dose verification on the bench is done by weighing a defined number of strokes and converting with the density of the fill, rather than assuming that one millilitre equals one gram.

The tolerance on the delivered volume should be agreed rather than assumed. A pump is a moulded assembly with elastomer seals, and its delivered volume moves slightly with the production lot, with the temperature of the product and the room, and with how hard and how far the consumer presses. Where a pack carries a claim that depends on the dose, that claim is written after a bench measurement with the real fill, not from the catalogue figure alone.

Pump Engine Materials and What They Have to Survive

A pump is a small multi-material assembly, and the parts that meet the product are not only the ones a buyer thinks of. The wetted set normally includes the dip tube, the housing and stem, the piston, the spring, the inlet and outlet valve elements, and the gasket that seals against the neck. Only the gasket and the dip tube are obviously in contact with the fill, but the chamber above them wets and rewets on every stroke, so the whole set is a compatibility question.

Material roles follow a familiar pattern. Dip tubes are usually polyethylene, chosen for flexibility and for resistance to a wide range of cosmetic fills. Housings, stems and collars are usually polypropylene. Pistons are commonly polyethylene or a thermoplastic elastomer. Springs are normally stainless steel, with grades specified by the customer where the formula is aggressive, and metal-free engines using a moulded plastic spring exist for formulas that cannot tolerate any metal contact. Valve elements may be a small ball or a flap, in glass, stainless steel or plastic. Neck gaskets are elastomer, commonly nitrile, EPDM, silicone or a thermoplastic elastomer, and this is the part most likely to be the weak link.

Compatibility is rarely decided by the majority of the formula and usually by its aggressive minority. A hydro-alcoholic or plain aqueous lotion is generally undemanding, and a standard polypropylene engine with a stainless spring is adequate. A fragrance-heavy or oil-rich product demands a soak test, because fragrance components and some vegetable oils can swell or extract certain elastomers, and a swollen gasket changes both the seal and the down-stroke feel. An acidic product, such as an alpha-hydroxy or vitamin C formula, pushes the same question onto the spring and the valve, and either a higher stainless grade or a metal-free engine is the safer baseline. A product containing alcohol at a high level has to be checked against the gasket and the piston rather than assumed compatible.

The test that settles it is simple to describe and is worth insisting on: immerse the wetted parts in the actual fill, at the filling temperature and at an elevated storage temperature, for a defined period, then re-measure weight, dimensions, colour, odour, seal and delivered dose. A part that gains weight has absorbed product and will behave differently in a month; a part that loses weight has given something up, which may be a plasticiser or an additive. A part that passes dimensionally but changes odour has still failed, because the pack will smell of the pump rather than the product.

Where the pack is subject to food-contact or cosmetic packaging rules in the destination market, the regulation that applies is named on the specification and a declaration of compliance is requested per wetted part. Regimes such as EU 10/2011 and EU 1935/2004 for plastics in food contact, and FDA 21 CFR for the equivalent United States route, set out what a supplier is expected to declare; ISO 22716 describes good manufacturing practice for cosmetic products. These are named here as the frameworks a buyer will be asked about. No claim is made here that any particular engine or any particular factory already holds such a declaration, and the document itself should be requested against the exact part number. The aluminium shell or covered collar seen on many packs is decorative and does not touch the product, so it carries no such requirement.

What a Thick or High-Viscosity Formula Demands From the Pump Chamber

Viscosity is the single number that most often changes the pump selection after the first sample. A thin toner or a watery lotion below roughly one thousand centipoise is easy for any engine to move. A standard lotion in the low thousands is the ordinary case. A cream above roughly six thousand centipoise starts to expose the limits of a general-purpose engine, and a product thick enough to hold a peak, or a paste-like formula, may be better served by an airless system than by a pump at all.

What changes inside the engine is the size of the paths rather than the size of the button. A thick product needs a wider inlet and outlet port, a wider valve seat and a longer, slower draw, so cream pumps are built with larger ports and a chamber shaped to pull rather than to suck hard. The dip tube bore matters as much as the engine: a narrow tube that is perfectly adequate for a lotion becomes a restriction for a cream, and the pump then pulls a partial chamber, which shows up as a short dose and a slow, gurgling refill between strokes.

Priming is harder with a thick fill. The chamber and the dip tube have to be filled with something that does not want to move quickly, so more strokes are needed before the first product appears, and an impatient filling line that stops priming early sends out packs whose first few consumer strokes deliver air. Some engines are supplied with a priming aid or a larger priming chamber for exactly this reason, and the number of priming strokes is a figure worth recording on the specification rather than discovering at the filling trial.

Two secondary effects follow viscosity. The first is drip or tailing: a thick product is drawn out into a short thread that hangs from the nozzle after the stroke, which is a cosmetic complaint rather than a leak, and it is reduced by nozzle geometry and by a clean cut-off at the end of the stroke rather than by changing the dose. The second is a product that dries in the nozzle between uses, forming a crust that partly blocks the outlet. An overcap limits it, but the more robust answer is a formula and a nozzle pair that does not leave a film behind.

Products carrying particles need their own note. A scrub with beads, a formula with a suspended powder or a gel with visible inclusions can jam a small valve seat or hold a ball valve open, so a wide-port engine or a valve designed for the particle size is required. The particle dimension belongs in the brief alongside the viscosity, because an engine that works perfectly on the base formula can fail on the version with the texture added.

Working Back From Dose Output to Capacity and Expected Number of Dispenses

The arithmetic that connects a dose to a bottle size is short, and buyers ask for it more often than for any other single calculation. The usable dispenses in a pack are the fill volume, less what the pack keeps for itself, divided by the dose per stroke.

The differences are the priming volume and the residual heel. Priming fills the chamber, the valves and the dip tube, and that product is never delivered to the consumer; its size depends on the engine, on the dip tube length and on the fill’s viscosity, and it is small but not zero. The residual heel is the product left below the end of the dip tube when the pump can no longer draw. Dip tubes are cut to a length that leaves a modest heel, because a tube long enough to reach the very bottom of a moulded bottle will rest against the base or the shoulder, seal itself against the glass and suck air instead of product. Leaving a heel of a few millilitres is the normal and correct outcome; a tube trimmed too aggressively trades a small amount of unusable product for a pack that stops working before it is empty.

A worked example makes the shape clear. A 100 ml fill with a 0.5 ml engine gives 200 strokes if nothing is lost. Allowing the priming strokes and a small residual heel, the plan is on the order of 190 usable dispenses. If the same fill is paired with a 1.0 ml engine, the count falls to roughly 95. Neither figure is a promise about a specific pack; both are the planning figure to carry into the negotiation, to be confirmed on a sample with the real fill.

The calculation is more useful in reverse than forwards. A brand claim such as “a two month supply at one millilitre per use, twice a day” implies about one hundred and twenty millilitres of fill, which points at a bottle size and at a dose grade before any drawing exists. Working that way, the pack size, the dose and the claim are consistent from the start rather than reconciled at the end. Two cautions belong with the arithmetic. A dose per stroke quoted from a catalogue is a nominal figure, and the delivered volume on a real pack shifts with the temperature and with how the consumer presses. And the fill volume has to be measured with the pump fitted, because the dip tube displaces product and a bottle filled to a mark on an open bottle will be overfilled once the pump is in place.

From Brief to Drawing to Sample to Production

The development sequence for a pump pack is short but has an order that should not be rearranged, because each step constrains the next one.

It begins with the brief: the formula and its viscosity at the filling temperature, the intended dose per use, the pack claim, the channel and the market. Viscosity and dose are the two entries that decide everything else.

Next comes the neck finish, and this is where a project is either kept on standard parts or moved onto a moulding programme. Selecting a standard finish from the common families lets the pump engine be taken from a stocked range, and the pairing of finish and engine is then a catalogue match rather than a development. Specifying a proprietary neck turns the same decision into a tooling project on both the bottle and the pump collar, with the schedule and the minimum quantity that follow from it.

The bottle drawing comes next, including the body height, because the dip tube is cut to reach the correct height above the base in that specific body. A rendering or a three-dimensional view at this stage is cheap and prevents a later surprise about how the pump and the shoulder read together. The pump selection then fixes the type, the dose grade, the material set and the closure, with the dip tube length recorded against the bottle drawing rather than against a capacity figure, since two bottles of the same capacity can have different internal heights.

The sample stage is where the arithmetic meets reality. Stock bottle, stock pump and the real fill are combined by hand and measured: delivered dose by weight, priming strokes to first product, leak behaviour upright and inverted, drip after the stroke, down-stroke force and the fit of the overcap or lock. A sample made with water rather than with the fill proves the dimensions and very little else, because viscosity is what the engine has to move.

Decoration and colour follow, since the actuator colour, the collar finish and any covering shell are applied to parts whose geometry is already frozen. The pilot run then exercises the filling line: filling with the pump in mind, closing torque, priming, locking, capping and a transport simulation. Production follows with incoming checks on each lot, and the four lots that should stay on one record are the glass, the pump engine, the gasket and the fill.

Pump Type, Dose Grade and Where Each Fits

The table sets out the pump families that come up most often on a glass cosmetic or personal care bottle, the dose grade each normally carries, the fill viscosity it suits, how it meets the neck, and the checks that should be made before it is ordered. It is a selection aid rather than a specification: the dose figure, the closure and the material set are confirmed against the pump drawing and the fill, and the order quantity and price follow from that.

How the Pump Meets the Bottle: Finish, Neck Height and Collar Depth

A pump closure is sold by finish, and the finish has to be read as three separate facts rather than one name. The first two digits give the nominal diameter in millimetres. The suffix describes the thread profile: 410 and 415 are the two profiles most common on cosmetic packs, with a 400 series used on some wider closures. Two closures of the same diameter but different suffixes do not necessarily interchange, because the thread pitch, the thread depth and the height at which the thread starts can all differ.

The third fact is neck height, and this is where most visible failures occur. A pump collar has a defined depth. If the glass neck is taller than the collar can cover, a ring of bare neck shows between the collar and the shoulder, which reads as a badly fitting pack even when the seal is sound. If the neck is shorter than the collar expects, or the shoulder rises early, the collar can land on the shoulder before the gasket seats on the neck land, and the pump then leaks through a path that no amount of tightening closes. Short-neck and long-neck pump variants exist for exactly this reason, and the neck height dimension belongs in the brief alongside the finish code.

Sealing itself happens at the top land of the neck, where an elastomer gasket in the pump’s collar is compressed against the glass. The closing torque exists to compress that gasket into its working range, not to hold the pump on. Under-torque leaves the gasket incompletely compressed and the pack weeps. Over-torque flattens the gasket past its elastic range, which is a permanent change, and it can also grip the pump body hard enough to slow the piston’s return between strokes, so an over-tightened pump under-doses as well as looking secure. The torque window belongs on the specification as a range, established on an assembled pack with the real gasket rather than on a bare bottle.

The dip tube is the fourth element of the pairing and the one most easily got wrong, because it is cut to the internal height of the bottle rather than to its nominal capacity. Two bottles that share a finish and a capacity can differ internally, and a tube carried over from one to the other will either touch the base or hover above the last few millilitres. A covered collar or aluminium shell is decorative and takes no part in sealing, and it must not be relied on to hide a gap that the collar depth should have closed.

The general decoding of finish codes, including how to read an unfamiliar designation and how to measure the dimensions that matter, belongs to the neck finish reference on this site. What this page owns is the other half of the pairing: which pump engine fits a given finish and neck height, and what that choice does to the dose.

Assembly Order, Transport Lock and the Tests That Follow Filling

Once the pump and the bottle are both chosen, the pack has to be closed in an order that leaves the consumer with a working dose. The sequence that works is fill, place and seal the pump, prime it, verify the dose, fit the transport lock, then fit the overcap and pack. The two steps most often reversed are priming and locking, and reversing them is expensive.

Priming has to happen at the filling site for two reasons. It removes the air from the chamber and the dip tube, so the first consumer stroke delivers product rather than a sputter, and it lets the dose be measured on a pack that is actually working. A pack that is locked before it is primed reaches the consumer with a dry engine, and the user’s first two or three presses are lost to priming with no product in between. The dose check then belongs after priming for the same reason: weighing the output of a pump still full of air measures the air.

A transport lock is any feature that prevents the actuator being pressed in the carton, and on a pump pack it is not optional. An unlocked pump can be actuated by handling and stacking, which doses product into the overcap and delivers a wet, half-empty pack with a soiled label. Air freight adds a second mechanism, because the pressure drop in a cargo hold pulls product through the pump path on its own even without a stroke. The common forms are a clip that holds the actuator down against the collar, a twist-lock or lock-up actuator position, a cap with a positive snap that also blocks the stroke, and an orifice plug. Their relative merit depends on the pack: a clip is easy to see and easy to remove, a twist-lock needs no separate part but depends on the consumer noticing it, and a snap cap is the neatest but demands a tighter cap-to-collar tolerance.

The tests that follow filling divide into pack tests and dose tests. The pack tests are a leak check on the closed unit upright and inverted, a leak or vacuum test where the product is volatile or the transit route demanding, a closing torque measurement on a sample with a calibrated gauge, and a transport simulation of the packed case that reproduces the handling the carton will actually see; published procedures such as ISTA describe the standard levels for such a simulation. The dose tests are the weight delivered per stroke, averaged over a defined number of strokes after priming and converted with the density of the fill; the number of priming strokes to first product; the down-stroke force and the actuator return time; a drip check for product left at the nozzle after the stroke; and a durability count of actuations. Where the buyer works to an AQL based sampling plan, the sample size and the acceptance number are agreed before the first run rather than after the first complaint, and the same checks are repeated at first-off, through the run and on cartons drawn from finished stock. Any change of glass, pump engine, gasket or fill means the checks are repeated, because the pack property being verified belongs to the combination and not to any one part.

Why a Pump Will Not Prime, Comes Back Slowly or Leaks

Three complaint patterns cover most pump failures, and each has a small set of causes that can be separated on one unit.

A pump that will not draw is almost always losing air somewhere on the suction side. The collar may be under-torqued, so the gasket never compresses and the chamber pulls air past the neck instead of product up the tube. The dip tube may not be pushed fully onto the pump inlet, which leaves a joint that looks assembled and leaks. The tube may be too short for the internal height of the body, so the lower end sits above the fill, or long enough to rest on the base or the shoulder and block itself. The fill may be too viscous for the engine, so the chamber pulls only partly full on each stroke and the pack gurgles. A valve element may be held open by a particle or by dried product from an earlier sample in the same pump. The diagnosis is to check the tube length and seat, then prime with the real fill and listen: a smooth draw that never reaches the nozzle points at the neck seal, and a slow, gasping draw points at the tube or the viscosity.

A pump that returns slowly, or not at all, is usually fighting something mechanical. The most common cause is an over-torqued collar, which compresses the gasket beyond its working range and can grip the pump body so that the piston cannot return at full speed. A formula that swells the elastomer or the piston has a similar effect and grows worse over the shelf life rather than better. Product dried in the chamber after a period of storage, a spring that was wrongly specified for the grade, and a cold room all slow the return as well, because the chamber has to refill through the dip tube and a thicker, colder product takes longer to arrive. Where a pack is slow from the first stroke, look at the closure and the engine; where it becomes slow after weeks on the shelf, look at the formula against the wetted materials.

A pump that leaks has to be separated into two faults that look alike. A true leak passes product out of the sealed path, normally because the gasket is missing, displaced or inverted, the collar is under-torqued, or the neck land has a chip or a mould seam that the gasket cannot bridge. It appears as wetness at the collar or the shoulder, and it will recur on every unit from that lot. A weep, sometimes called neck creep, is product that climbs the thread and shows at the neck ring on a low-viscosity fill; it is a cosmetic failure rather than a seal failure, and it is addressed by the collar and thread geometry rather than by torque. A droplet left at the nozzle after each stroke is neither of these, and it is a cut-off or nozzle-geometry issue. One diagnosis covers all three: on the same unit, measure the gap between collar and neck land, prime with the real fill, watch where the first wetness appears, and weigh the dose after a defined number of strokes. That single routine separates a closure fault from a pump fault from a formula mismatch.

Where Pump Selection Stops and Other Pages Take Over

The bottle body, in every capacity and finish the site carries, is described in the essential oil bottles and small glass bottle hub, and that is where the choice of glass belongs. How the chosen pump is physically fitted to a filled bottle, including the press or crimp operation, the closing torque window and the drop-rate recheck, is the subject of the dispensing closure assembly page, and a change of fitting method should be decided there rather than here. The atomising route for thin and alcohol-based fills is on the fine mist spray pages. Reading an unfamiliar finish code, and measuring the neck dimensions that go with it, is covered by the neck finish reference on this site.

What stays on this page is the selection itself: which of the three dispensing routes the formula needs, which dose grade matches the claim, which material set can live with the fill, how many dispenses a capacity will deliver, and which pump engine will land on the neck the bottle already has. A question about which bottle to choose belongs to the bottle pages; a question about how to attach the pump belongs to the assembly page; a question about which pump and which dose belong here.

Frequently Asked Questions About Lotion Pump Bottles

How do I know whether I need a lotion pump, a fine mist sprayer or a pressed dropper?

Start from the viscosity of the fill and the output you want. A lotion pump is a positive-displacement device that pushes a fixed volume out of a metering chamber and handles creams, lotions, gels and thicker serums; it is the right answer when the product is thick enough to hold its shape and the pack claims a dose per press. A fine mist sprayer atomises the product through a small orifice and needs a freely flowing, low-viscosity liquid such as a toner or an alcohol mist; a lotion put into a sprayer either will not draw or arrives as a coarse jet. A pressed dropper delivers a drop-wise or very short dose and suits a serum, an oil or an expensive treatment where the consumer counts drops. If the formula is thick, choose between a pump and an airless system; if it is thin and the output must be a mist, it is not a pump page.

What dose per stroke should I specify?

Work back from how the product is used rather than from the catalogue. A face serum or a treatment is often around 0.2 to 0.5 ml per use, a face lotion about 0.5 ml, a body lotion about 1.0 to 2.0 ml, and a hand wash, shampoo or body wash around 1.5 to 3.0 ml. Choose the nearest fixed grade, because the dose is set by the swept volume inside the engine and cannot be tuned from outside by fitting a larger button. Then check the consequence: a larger dose needs a firmer press and more bottle stability, and it empties the pack sooner. The delivered volume is a volumetric figure, so verification on the bench is done by weighing a defined number of strokes with the real fill.

Does the pump material matter if the spring never touches the product?

It matters if the spring is inside the chamber that wets and rewets on every stroke, which is the usual arrangement. The wetted set normally includes the dip tube, the housing and stem, the piston, the valve elements and the neck gasket, and the spring sits in the same product path on most engines. The part most likely to fail is the gasket rather than the spring, because an elastomer can swell or be extracted by a fragrance-heavy or oil-rich fill, and a swollen gasket changes both the seal and the down-stroke feel. The test is a soak of the wetted parts in the actual fill at the filling and storage temperatures, followed by re-measurement of weight, dimensions, odour, seal and dose. Where the formula cannot tolerate any metal, a metal-free engine with a moulded plastic spring is available.

Can the same glass bottle take both a pump and a plain cap?

It can, provided both closures are made for the same finish and the same neck height. A screw pump and a screw cap that share a finish code will both land on the neck, and the pack can then be offered in two versions from one bottle. Two cautions apply. A finish code is read as diameter plus thread profile, and closures of the same diameter with different profiles do not necessarily interchange, so the pairing is confirmed rather than assumed. And the neck height still has to suit both closures: a pump collar and a cap skirt of different depths can each cover the neck, but a short cap on a tall neck leaves the same ring of bare glass that a short pump collar leaves.

Why does the pump not work the first time the consumer uses it?

Because a pump that was never primed arrives with air in its chamber, valves and dip tube. The first two or three strokes are spent drawing product up the tube rather than dispensing it, so the consumer’s opening experience is a sputter or nothing at all. Priming at the filling site removes the air and lets the dose be measured on a working pack, and it must be done before the transport lock is fitted. If a pack is primed and still fails at first use, the cause is usually on the suction side: a dip tube not fully pushed onto the pump inlet, a tube too short or too long for the internal height of the body, or an under-torqued collar that lets air past the neck seal.

What is a transport lock and do I need one?

A transport lock is any feature that stops the actuator being pressed before the consumer opens the pack: a clip that holds the actuator down, a twist-lock or lock-up actuator position, a snap cap that also blocks the stroke, or an orifice plug. On a pump pack it is normally necessary, because an unlocked pump can be actuated by handling and stacking, which doses product into the overcap and delivers a wet, partly empty pack with a soiled label. Air freight adds a second mechanism, since the pressure drop in a cargo hold can pull product through the pump path with no stroke at all. The lock is fitted after priming and after the dose check, and it belongs in the transport simulation that the packed case is put through.

What should I send to get a pump and capacity proposal?

Send the fill with its viscosity at the filling temperature and its density, the dose you want per use and how the consumer will use it, the finish code or the neck drawing of the bottle, the internal height of the body if it is already fixed, the pack claim if there is one, and the channel and market the pack is going to. With that set, a pump type and dose grade can be proposed together with the dip tube length and the closure, and the expected number of dispenses can be worked out against the fill volume. Where a soak test is needed for the wetted materials, the fill sample and the storage conditions should be included. Order quantities, unit prices and lead times are quoted separately against the finished specification, because each follows from the drawing and the destination rather than from the pump type alone.

Send the fill viscosity, the dose per use and the bottle’s finish code or neck drawing, and a pump type, dose grade and dip tube length can be proposed with the expected dispense count for the capacity you have in mind.