Which type of pump is generally not used for aquatic herbicide applications?

A roller pump is generally not used for aquatic herbicide applications primarily because of its design and the nature of the fluids it is intended to handle. Roller pumps operate by trapping fluid in a chamber and forcing it out as a roller moves over an opening. This design is better suited for transferring clean, non-abrasive liquids. Aquatic herbicide applications often involve the use of various herbicide mixtures, which may contain abrasive particles, chemicals, or foaming agents that could damage the pump or affect its functionality.

In contrast, diaphragm pumps, gear pumps, and centrifugal pumps are more versatile in handling the types of liquids involved in herbicide applications. Diaphragm pumps are effective for precise application and can handle a range of fluids with solid content without risk of damage. Gear pumps provide consistent flow and are suitable for thicker liquids, while centrifugal pumps efficiently move liquids, making them ideal for many pumping tasks in herbicide applications.