Dosing Pump

Dosing Pump

A dosing pump, or chemical injection pump, is a pump used to inject or add a specific amount of chemical liquid into a larger volume of liquid (usually water). For example, injecting liquid chlorine into pool water as a disinfectant. Dosing pumps are a type of positive displacement pump, with common types used for chemical injection being diaphragm, piston, and plunger pumps. Unlike typical pumps, the flow of liquid pumped by a chemical injection pump is intermittent and in small doses. These pumps usually have a low flow rate but high pressure/head, and their flow rate can be adjusted as needed.

How Dosing Pumps Work:

A dosing pump operates by drawing a measured amount of liquid into its chamber and then injecting the chemical into a tank or pipe containing the target liquid. These pumps are powered by an electric motor or air actuator and are equipped with a controller that regulates the pump's on-off cycles and flow rate.

Types of Dosing Pumps by Action and Pumping Mechanism:

1. Diaphragm Pumps (Constant Injection):
• Mechanism: Uses a diaphragm, piston, and valves at the inlet and outlet to fill and empty the chamber.
• Operation: When the plunger retracts, a specific amount of chemical is injected at a preset rate, often as a percentage of the maximum flow rate.
• Adjustability: Some models allow for varying the dosage rate.
2. Diaphragm Pumps (Pulse Injection):
• Mechanism: Also uses a diaphragm mechanism but injects the chemical in pulses instead of a constant flow.
• Operation: A solenoid draws the chemical and injects it in pulses, with the flow rate determined by the time between pulses.
• Cost and Complexity: These pumps are simpler and more affordable but less precise than constant injection pumps.
3. Lobe Pumps:
• Mechanism: Rotary lobe pumps allow a specific volume of liquid to pass through gear-like impellers.
• Suitability: More suitable for high-viscosity liquids that can self-lubricate to reduce wear.
• Accuracy: Not as precise as diaphragm pumps and not designed for low flow rates, making accuracy challenging.
4. Peristaltic Pumps:
• Mechanism: Extremely precise in dispensing liquids, with a flexible curved tube allowing liquid to pass through while rollers move along the tube to push the liquid forward.
• Operation: The rollers' movement creates a stable primary flow.

Applications:

Dosing pumps are widely used in various industries due to their precision and versatility in controlling chemical injection rates. Common applications include:

• Water Treatment: Injecting chemicals like chlorine, coagulants, or pH adjusters.
• Chemical Industry: Dispensing chemicals accurately in production processes.
• Food and Beverage Industry: Adding additives, flavors, or preservatives.
• Pharmaceutical Industry: Producing medicines with precise dosages.
• Agriculture and Aquaculture: Delivering fertilizers or nutrients in irrigation or aquaculture systems.

Advantages:

• Efficiency: Reduces chemical waste and improves process efficiency.
• Safety: Minimizes the risk of overdosing or underdosing in critical applications.
• Flexibility: Suitable for a wide range of liquids and applications, with adjustable flow rates to meet specific needs.