This pump is used for hand lotions, i.e. thick (high viscosity) liquids.
There are two metal balls inside this pump. The large lower ball fits inside the first few turns of the spring. The middle turns of the spring are of reduced diameter so they act as a stop for the ball.
This particular version of hand pump is patented by Calmar, Inc. though many fairly similar pump mechanisms exist.
Impeller Mechanism, Basic
Probably this is the most versatile pump of all. Impeller mechanisms are the basis of thousands of types of pumps.
The number of blades can vary from 1 to 10 or more. They operate over a wide speed range — from less than 30 to more than 3000 RPM.
Impeller pumps are excellent for moving impure liquids since they do not clog very easily. For very impure liquids such as sludge, a single blade is sometimes used.
Impeller pumps range in diameter from less than a quarter inch to 10 feet or more. Sometimes they have diffusers to increase efficiency.
Sometimes the output of one impeller is fed directly into another impeller to increase the head. As many as six or ten might be linked together, or connected in two facing sets to double the output and even the pressures on the shaft and pump casing.
Impeller, Single Lobe
A single vane impeller is almost impossible to clog, therefore, it is commonly used for liquids that contain solid materials in suspension.
Impeller Mechanism, 2-Lobe
By having only two vanes, the risk of clogging from foreign matter in the fluid being pumped is reduced over a pump with more vanes. (For even messier fluids a single vane can be used.)
This type of pump might be used for pumping sludge or other contaminated liquids. It is also common for moving liquid paper stock.
All of the head in an impeller type pump is created by the impeller itself. The rest of the parts induce losses to the maximum head.
Losses are induced by friction of the fluid against the sides of the parts, by mechanical friction of the pump shaft, and from hydraulic efficiency losses such as fluid eddies and changes in direction (which takes energy).
Impeller Diffuser Pump
The efficiency of the Impeller Pump can be greatly increased by the addition of stationary Diffuser Vanes. Large Impeller-diffuser pumps can achieve efficiency ratings of 90 percent.
The number of diffuser vanes is always different than the number of impeller vanes. This is so that the edges of the rotating impeller vanes do not come close to all the ends of the diffuser vanes at the same time.
This prevents thumping or knocking, and excessive buildup of pressures.
In this drawing the innermost set of vanes revolves and the outer set is stationary.
Impeller Diffuser, Multi-Stage
Multi-stage impeller pumps have substantially increased heads over single-impeller types.
In the model shown, there are five rotating impellers in sequence, with the intake from the lower hole on the left and the outlet at the lower right. The upper two holes connect to the lower holes, balancing intake and outlet pressures on the shaft.
The liquid swirls with the rotation of the pump. As many as 12 separate impellers are often connected together to increase flow rates and head.
In many models the fluid enters at either end and works towards the middle, or enters one end and immediately after the first impeller, is sent to the opposite end to the second impeller, then back to the first end, and so on, exiting in the middle.
The advantages of such a system are improved pressure balance on the shaft and relatively low pressure around the seals. On the pump shown the right-hand seal has the pressure of four stages pushing against it.
Infusion Pumps are used to deliver very small quantities of drugs over long periods of time. They are also commonly called Syringe Pumps.
A worm gear (shaft) slowly turns, moving the plunger of the syringe in, and pushing the medication out. These can also be used in reverse to withdraw fluids.
Here the action is shown much faster than it usually would be. The injection might take place over a period of many hours.
A typical infusion pump might have a flow rate range from .2 cubic centimeters (cc) to 500cc per hour. At .2cc per hour, a 10cc syringe would require 50 hours to empty.