Irrigation Emitters

What an emitter does

An emitter releases water from the line at a controlled rate — the "L/h" (litres per hour) figure on every drip line specification. It's a tiny hydraulic component: an internal channel or labyrinth that turns line pressure into a steady drop rate. Two properties matter most: its flow rate (how much water) and its uniformity (how consistently it delivers across the system, and through its life).

Emitters are usually inline — built into the drip line at fixed spacing — which is the standard for Kenyan drip systems. Separate, point-source drippers (1/2″ or 3/4″ fittings with a single emitter) are used per plant or per pot where you want independent application.

Types

Flow rates — the numbers on the bag

Common inline flows in Kenyan systems: 1.6, 2.2, 2.7 and 4 L/h, with orchard and point-source emitters going to 8 L/h and above. The choice is hydraulic, not preference:

• The crop's daily water demand per plant ÷ the emitter flow = the run time per day (or the sessions needed). A tomato wanting ~5–10 L/day in the hot season takes 2–4.5 hours on a 2.7 L/h emitter — reasonable. On a 1.6 L/h emitter, the same day takes 3–6+ hours — the system starts asking for more lines or longer runs.
• Soil type shapes it too: sandy soils benefit from shorter, more frequent runs; a higher-flow emitter on the same crop suits clay where water moves slowly and long runs waste pressure to infiltration.
• Line length and pressure set what the flow can actually be at the far end — which is why the flow is chosen with the line diameter and layout, never before them.

That's the design calculation in miniature — the full method is in the system design guide.

Uniformity — the number that doesn't get printed

A well-matched system delivers within a few percent between emitters, start to end. Two things break uniformity: pressure variation (slopes, long lines, pump drift — the case for PC emitters or better zoning) and partial clogging (each clogged orifice shifts flow to its neighbours, and the pattern degrades invisibly until a row starts to lag). The common problems guide shows what degraded uniformity looks like in the crop — because that's usually how it's first noticed.

Orifice size and clogging

Every emitter has an inlet orifice — typically 0.8mm to 1.4mm on common inline emitters. Anything in the water smaller than that orifice goes in and stays. That's the entire reason filtration exists: the filter's mesh or media is specified against the emitter orifice size (a common rule of thumb keeps filtered particles well under a quarter of the orifice). Two further notes: flush regularly (sediment settles in the line, not just the filter) and check line ends first when a row underperforms — the end emitters take the worst of it.

Choosing emitters

The sequence mirrors the line choice: crop demand → flow rate → spacing from in-row spacing → PC or standard from the layout → orifice size confirmed against the filter. It all lives in one design document, because changing one number moves the others. For your farm's specification: request a quote, or read the drip irrigation guide to follow the logic yourself.