What is the purpose of the in-line orifice in a direct metering system?

The purpose of the in-line orifice in a direct metering system is to ensure that the correct amount of herbicide is metered into the system. The orifice acts as a precise measuring point that regulates the flow rate of the herbicide as it is introduced into the main water stream. This is crucial because applying the right dosage of herbicide directly affects the efficacy of the treatment and helps to prevent over-application or under-application. By providing an accurate and consistent way to inject the herbicide, the orifice contributes to both effective weed control and environmental stewardship.

The other options do not accurately describe the function of the in-line orifice. While a pump may be necessary for other types of systems, the orifice does not eliminate the need for one; rather, it works alongside or within those systems. The in-line orifice does not directly mix the herbicide with water; mixing typically occurs downstream where turbulence is created as water flows. Lastly, it does not serve to strengthen the suction line; an orifice is focused on flow measurement rather than structural integrity of the piping system.