To select a liquid filler there are decisions to make:
Speed, Price, Capabilities, Convenience, Ease of operation, Reliability etc...
Likewise in the manufacturing of a filling machine similar considerations apply.
From the very many alternatives, we selected positive displacement gear pump as the preferred technology.
Any type of product can be handled from light liquids through to heavy creams and pastes.
Each nozzle has its own independent volumetric pump giving the highest possible accuracy.
Variances in viscosity through a batch are less likely to affect the fill.
Setup and changeover is simple and quick.
Product can be fed either from a hopper above or from a drum below.
The gear pump is always immediately ready to fill again after the previous fill.
There is no suction stroke to wait for, as with piston fillers.
There are no limitations on the volume dispensed. From milliliters to gallons it is simply how long the gear pump runs for.
Accuracies of ±0.5% are easily achievable.
The adjustment of 1 nozzle does not affect any other nozzle.
The units are very compact.
Other advantages we have built in to the inherently good technology include:
Stainless steel cabinets and contact parts.
Touch panel control.
Plug in networkable design allowing multiple units to be combined together to form a system at any time.
Rugged sanitary gear pump with few components as the heart of the system.
Frequency variable speed drives.
Automate at any time with a plug in kit.
Filling Speeds & Technologies
Below is more information about other technologies so you can evaluate if you feel that you need to know what else is out there.
First you need to know your target speed.
There are three speed categories for filling machines:
Automatic inline fillers
Automatic rotary fillers
Each of these three can use several alternate technologies for filling.
Manual fillers go as fast as you can manually change bottles over either with 1 or 2 nozzles (unless you are a Martian with 3 hands). Depending upon the fill volume the maximum speed with 2 nozzles and 2 hands is likely to be topped out at 30 or even 40 bottles a minute for relatively small fills (100ml). Even then you will need to consider how to cap, label, and carton etc. the bottles down stream.
Multiple small units are becoming more popular as they have faster changeovers which you have to consider in your overall productive day.
The next decision will be between automatic inline and automatic rotary.
Automatic inline machines range from a single nozzle up to 12 (or more) nozzle machines. Normal speed ranges of an inline filler are between 60-150 containers per minute. Higher speeds enter the domain of the rotary filler which can operate at speeds in excess of 1000 containers per minute.
Inline fillers are quicker to changeover and easier to setup than rotary fillers, and normally don’t require change parts for each size of container, but rotary fillers once setup can give consistently high speeds.
Consideration has to be given to run (batch) sizes, cost of change parts, speed of changeover (down time) when selecting between rotary and inline fillers. Long runs, few changeovers, favor rotaries and the reverse favors inline.
Whether manual or automatic, there are three major technologies, each of which can be further sub-divided.
Vacuum, Gravity & Pressure
Vacuum, Gravity & Pressure Fillers
Vacuum, gravity, and pressure fillers use a source of power whether it is vacuum (to suck), gravity, or pressure to deliver liquids to multiple nozzles from a single source (tank, manifold) of product. They control the fill either with a nozzle that will overflow to a collector, when the product reaches the right level in the container, or through a nozzle that closes after a preset but adjustable time.
Typically these are the least expensive fillers, each has its pros and cons, with the vacuum handling the thinnest liquids into bottles that will not collapse when vacuum is applied to it through to time pressure fillers that can handle free flowing but thicker products.
Issues with these technologies involve having to collect and recycle overflow, only having a fill to a level rather than to a correct volume, and having issues with fill accuracy on time pressure fillers. Time pressure fillers require strict regulation of the pressure, time and product consistency (temperature/viscosity), a slight alteration of any one would affects the fill.
Usually these systems are used with thinner rather than thicker products and with the less expensive products such as water or cheap chemicals. (Accuracy not an issue)
Positive Displacement Fillers
Positive displacement fillers have an individual pump or piston for each individual filling nozzle. They are mid-priced but more versatile. They include piston fillers, gear pump fillers, lobe pump fillers, and progressive cavity fillers.
A known amount of product is dispensed volumetrically. A piston pulls the exact quantity of product into its cavity and then dispenses it into the container. The positive displacement gear pumps or progressive cavity pumps have many small cavities which are counted and dispensed cumulatively into the container.
All systems are very accurate, and can handle a very wide range of product consistencies from thin to thick.
Net Weight Fillers
Net weigh fillers weigh an empty container or relies on a container of a known weight then places it manually or automatically onto a scale. The container is then filled with product while the scale measures the weight and determines when the correct weight is achieved stopping the product flowing.
The nature of the weighing mechanisms is such that it requires considerable machinery to get any reasonable fill speed. Net weigh fillers are often used in large drum filling applications where containers per minute is not crucial. Most liquid products are sold by volume and not by weight, but valuable product sold by weight may require an exact weigh filler to justify the expense of the machinery.