Spray Guns and Lances

A spray gun is the interface between a pressurised line and a human hand. Unlike a fixed nozzle, it has a trigger or valve the operator controls, which means the selection problem is as much about ergonomics and inlet as about the spray pattern. The lance is the extension that puts the pattern where the hand cannot reach.

This covers washdown guns, air-assisted guns and agricultural boom guns — the hand-held end of industrial and crop spraying.

Flow, Pattern and Inlet

Flow is set by the gun’s internal orifice and the supply pressure, and a wash gun can pull a lot of volume at line pressure — relevant wherever water or chemical is metered or shared.

Pattern follows the fitted tip: flat fan for even wash or boom coverage, jet or cone for targeted work. The gun is the valve; the tip is the nozzle, and the two are selected together.

Inlet — BSP thread size and type — must match the supply hose. A mismatch is a leak or a poor fit, not a spray problem.

Wash, Air-Assisted and Boom

Wash guns are built for high flow and a robust body that survives being dropped and hosed down. Flat or jet pattern, often with a variable tip.

Air-assisted guns add a stream of air to shape and project the pattern, useful where atomization or reach matters more than raw volume.

Boom guns are the hand-held end of agricultural spraying — high flow, flat-fan tip, built to push chemical across a row or a field edge.

The Lance Extends Reach

A lance is a rigid extension with the nozzle at the far end and the trigger at the hand. It puts the pattern into a vat, over a hedge, or down a pipe without the operator standing in the spray. The longer the lance, the more the pattern steadiness depends on supply pressure and a well-matched tip.

Reference Specifications

Flow quoted at 3 bar. Inlet thread must match the supply.

How to Select a Spray Gun or Lance

• Duty — washdown, crop spraying or targeted application sets the gun type.
• Flow versus supply — confirm the line can deliver the gun’s flow at pressure without sagging.
• Pattern via the tip — pick the flat / jet / cone tip for the job; the gun is the valve.
• Inlet thread — match BSP size and type to the hose; fit is decided here.
• Reach — add a lance where the hand cannot go; longer lances need steadier pressure.
• Build for the environment — PP and stainless for wash and chemical, lighter alloys for occasional crop use.

Frequently Asked Questions

Wash gun or boom gun for crop work? Boom gun — high flow, flat-fan tip, built to push chemical across a row. A wash gun wastes most of its volume outside the target.

Why does my lance pattern wander? Usually supply pressure sag under the longer column, or a tip not matched to the flow. Steadier pressure and the right tip steady the pattern.

What inlet do I need? Match the gun’s BSP thread to the supply hose. A mismatch leaks or fits poorly regardless of spray quality.

Can I change the pattern on a gun? Yes — by changing the tip. The gun is the valve; the nozzle tip sets the pattern.