How to choose the right pump

Thread, tube and dosing: how to choose the right pump so that it dispenses the product correctly and how to avoid leaks

Let's start with the most important rule:

There is no perfect pump, only well-tested ones. Even if all parameters are perfectly matched on paper, ultimately only after tests can you be sure that the pump fits the bottle and the product.

According to what parameters should you choose a pump?

There are three main ones: thread, dosage and tube length.

GWINT

In professional jargon, thread "size" is a term that refers to the size and type of thread on the outside of a container neck or the inside size of the neck. The standard designation of the thread size is with a slash or hyphen: 24/410, 24-410. The first number (24) is the thread diameter in millimeters, the second is the coded number of thread turns.

How should a thread be measured?

The diameter of the pump or nut is measured from the inner walls of the thread:

The number after the dash indicates the number of thread turns. If the coil passes through the thread once, it is marked 400. If the coil makes one and a half turns, it is 410. If it makes two full turns, it is 415, and so on. Most often we see 410 and 415, i.e. one and a half and two turns.

TIGHTNESS

Unfortunately, the appropriate thread size does not guarantee full tightness. Each manufacturer has its own permissible production deviations and they appear in both the pump and bottle thread dimensions, and the total difference between them may be up to a millimeter or more. There is only one solution: test the pump with each container and with each product that will be used in a given package.

In some cases, a bottle with more coils may fit a pump or a cap with fewer coils. For example, a 24/410 cap may fit well on a bottle with a 24/415 thread, but never the other way around. The set can also be completely tight for specific products, depending on their density or viscosity. However, this should always be tested

DOSAGE

Pumps are conventionally divided into two types: lotion pumps - intended for products that are used in large quantities at one time: shampoos, liquid soaps, shower gels, body care and the like. They are most often used for bottles with a capacity of 150 milliliters and larger, and with one press they dispense a portion from 1,5 to 5 milliliters of the product.

The second type are cream pumps with a small dose per press: face creams, serums, makeup products and so on. They are usually used for bottles with a capacity of no more than 150 milliliters. The dosage for such pumps is usually within 1 milliliter per actuation - it can be 0,1 ml, but can be up to 1,5 ml.

Another important factor when dosing is the above-mentioned product density and the presence of solid particles in it.

Most pumps are intended for products with a cream or gel consistency. There are special pumps for watery, oily or very "plasticine" products, manufacturers always inform about this in the description. Simply choosing a pump with a thread that fits the bottle and the right dose is sometimes not enough. When placing an order, please specify the consistency of the product.

The situation is similar with the presence of solid particles in the product. Problems are rare with a 5 ml pump, but with small dose cream pumps things can get more complicated. Most cream pumps are designed for a homogeneous mass, without hard particles. As with products that are too liquid or too thick, granular or particulate formulations fall into a separate category. Therefore, when placing an order, we indicate not only the density of the product, but also the presence of hard particles in its mass.

TUBE

The perfect tube for thinner products: soft and long enough for the tip to curl slightly at the bottom of the bottle. For denser products: this will be a harder tube with a larger diameter that almost reaches the bottom. There should be a space of about 2 mm there. With such configurations, the pump will pump out the product as much as possible.

When the tube is shorter than necessary, the pump only works well when the bottle is full, and as soon as it starts to empty, the pump pumps air instead of cream.

Tubing that is too long can cause two problems.

When the tip of the tube rests on the bottom, it blocks product and air, causing dispensing problems. Moreover, if the tube is hard and puts a lot of pressure on the bottom of the bottle, it may bend, making it unstable.

When the tube is placed with its long end at the bottom of the bottle, product residues, especially if it has a thick consistency, accumulate on the adjacent walls. In the case of liquid or gel soap, this is not a major problem - just tilt the bottle so that the residue flows in the desired direction. However, if we are talking about a cream or body oil, you will need to shake the bottle before each use.