The structure of a foaming pump typically consists of the following parts:

1. Pump Head: The pump head is the topmost part of the foaming pump that is pressed or squeezed to dispense the foam. It usually has a cylindrical shape with a nozzle or opening through which the foam is released.

2. Dip Tube: The dip tube is a long, thin tube that extends from the pump head into the bottle or container where the liquid product is stored. It allows the pump to draw the liquid from the bottom of the container.

3. Collar: The collar is the threaded or snap-on component that connects the pump head to the neck of the bottle or container. It secures the pump in place and prevents leakage.

4. Chamber: The chamber is the key component of the foaming pump responsible for creating foam. It consists of several sub-parts:

a. Foamer Sleeve: The foamer sleeve is a cylindrical piece that surrounds the dip tube and fits inside the pump head. It contains small holes or slits that allow air to mix with the liquid as it is dispensed, creating foam.

b. Foamer Cap: The foamer cap is a cover or lid that encloses the foamer sleeve and provides support to the pump head. It typically has a plastic mesh or filter that further helps in producing a consistent and fine foam.

c. Piston or Plunger: The piston or plunger is a movable component inside the chamber. When the pump head is pressed or squeezed, it moves downward, forcing the liquid product to move up through the dip tube and into the foamer sleeve.

5. Spring: The spring is located inside the chamber and assists in the upward movement of the piston or plunger. It provides the necessary pressure to create the foam and also helps in resetting the pump after each use.

These are the basic components of a foaming pump. However, the exact design and structure may vary depending on the manufacturer and specific product requirements.