Irrigation

RAIN LING Air-Release Valves

RAIN LING's air-release valve lets trapped air out of irrigation pipelines and helps stop vacuum forming when the system starts and stops. RAIN LING lists air capacity up to 360 m³/h, an operating range of 0.3–15 bar and BSP or NPT male threads, in a UV-resistant PP body. Typical spots are high points, filter outlets and next to control valves. The 360 m³/h figure is air volume, separate from the water flow in your main. To size the valve, describe your filling, running and draining events and ask RAIN LING for the airflow curve of the size you order.

Lingxing Irrigation Technology (Ningbo) — RAIN LING ↗

Prepared by CropEquip Editorial · Sources checked 2026-10-12

Build my procurement brief

What 360 m³/h means

RAIN LING describes 360 m³/h as air-volume capacity. Main-line water flow, zone flow and any pressure setting are different figures. Ask whether the 360 m³/h is quoted at standard or actual air conditions.

The page gives no curve pairing airflow with pressure difference for each size, and no orifice size or test method. The 15 bar top limit and the 360 m³/h peak are best read as two separate catalogue limits. Ask for the expulsion and intake curves of the valve offered, with their reference conditions and direction of flow, then work out filling rate, protected length and draining time from those curves.

Sources [1] [2] [3]

Describe the air events in your system

RAIN LING mentions trapped-air release and vacuum prevention at startup and shutdown. Describe each event in your pipeline so the supplier can name the function and curve that applies. Emptying the line at shutdown is a separate job, handled by RAIN LING's automatic drain valve.

System event	What to ask RAIN LING
Filling	Send pipe volume, layout and filling rate, and ask for the air-expulsion curve that covers it.
Draining or shutdown	Describe how the line drains and ask for the air-intake and vacuum response. The 0.3–15 bar range covers positive pressure only.
Air during normal running	Ask whether the valve also releases small air pockets while the line is under pressure, and at what rate.
Valve and pump switching	Send your switching sequence and pipe details, and ask for the orifice and surge response of the valve.

Sources [1] [5]

Published specifications

Read each value with its stated conditions, and ask the manufacturer for any limit not listed here.

Specification	Published value	Meaning / limit
Function	Automatic release of trapped air; vacuum prevention at startup/shutdown [1]	Ask which of filling, draining and running-under-pressure the version you order handles.
Air capacity	Up to 360 m³/h of air [1]	Air volume. Ask for the reference conditions and the airflow-versus-pressure curve for each size.
Operating range	0.3–15 bar [1] [5]	Positive working pressure. Air intake under vacuum needs its own figures.
Connections	BSP or NPT male threads; gallery includes one-, 1.5- and two-inch labels and a 6-point image [1] [2] [3] [4]	State the thread standard and size on the order and request the full drawing.
Construction	UV-resistant PP body construction [1] [2]	Ask for seal materials and temperature and water-quality limits.

Thread, size and internal air path

The gallery shows several similar orange-bodied valves with different male connections. Order by full code with the thread standard, and get the internal air path from the drawing.

What RAIN LING shows	What to put on the order
BSP or NPT	Both are offered. State the standard, nominal size and sealing method, and request a mating drawing.
Gallery size labels	Images are labelled one, 1.5 and two inches, plus a 6-point image. Ask for the orifice diameter and capacity of each size.
Chinese VP codes	The Chinese parts directory lists VP75, VP100, VP150 and VP200. Ask RAIN LING how these codes relate to the English sizes and to the 360 m³/h figure.
Outlet and access	Request the outline, required orientation, clearance and outlet arrangement for your build.
Other limits	Temperature and water quality, seals, air reference conditions and maintenance instructions.

Sources [1] [2] [3] [4]

Placement and surge

UF/IFAS explains water hammer as the result of sudden changes in water velocity, and discusses valve closing time and choosing the right air-vent orifice. Assess surge for your own filling, draining and switching conditions with the valve you select. Compare the result with the pipe's working and burst pressure, which our guide to specifying irrigation hose and pipe explains.

RAIN LING suggests pipeline high points, filter outlets and places near control valves, and its gallery shows farm and greenhouse installations. Plan the exact locations from your pipe profile. If those control valves are the maker's EVA/EVD solenoid valves, mark each one on the profile; other makers' valves sit in our irrigation category.

For your order, keep the model, thread and orifice, the expulsion and intake curves, the pressure and surge response and the current instructions together. Ask RAIN LING separately about vacuum limits, frost protection and drainage if you need them.

Sources [1] [2] [3] [5]

Buyer questions

Is 360 m³/h the water flow the valve handles?

No. It is air volume. The valve sits on the line and does not carry the irrigation flow. [1]

Does the 0.3–15 bar range cover vacuum?

It covers positive working pressure. Ask RAIN LING for the air-intake curve and vacuum conditions. [1] [5]

Does the largest thread give the full 360 m³/h?

RAIN LING gives no size-by-size capacity table. Ask for the pressure and airflow curve of the size you buy. [1] [2] [3]

Will the valve drain standing water?

It is described as an air valve. If you need drainage, plan a drain point and ask RAIN LING what it recommends. [1] [5]

Prepare a model-specific brief

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Sources

Specifications come from the manufacturer's publications listed below, with the date each was checked.

RAIN LING official air-release valve description
manufacturer · Checked 2026-10-12
Air capacity up to 360 m³/h, 0.3–15 bar, UV-resistant PP, BSP/NPT male threads and the startup and shutdown air and vacuum function.
Original one-inch valve photograph
manufacturer · Checked 2026-10-12
Male connection and orange outlet and body.
Original four-profile and installed-view illustration
manufacturer · Checked 2026-10-12
Four valve profiles and installation views, including an outlet near pressure gauges.
Chinese official parts-directory air-valve identifiers
manufacturer · Checked 2026-10-12
Lists air-valve codes VP75, VP100, VP150 and VP200.
UF/IFAS Cir1425: surge and air-vent context
official disclosure · Checked 2026-10-12
Pages 5–6 cover velocity change, valve closing time and choosing an air-vent orifice to limit surge.

Report a correction through our contact form, quoting RAIN LING Air-Release Valves and the relevant specification.