Description

Impact rain gun sprinkler 

Eunidrip irrigation systems stocks impact rain gun sprinkler that irrigates various diameters per farmer request or land acreage.

Impact rain gun sprinkler discharges water ranging from 10000 liters per hour to 32000 liters per hour.

The commonly used rain  rain gun sprinklers have a wetting diameter or water throw ranging from 48 meters to 72 meters but the commonly used diameter is 56 meters.

These diameters are very critical in designing the amount of water required at the source and the number of impact gun sprinklers the farm requires.

Uses of impact rain gun sprinkler

Impact gun sprinklers are normally applied in irrigating pastures, tall bushes orchards and maize plantations of large acreage.

This is because of their water usage and radius of throw which covers large distances within a single rotation.

Stocked rain gun sprinkler at Eunidrip

The available impact gun sprinklers in our stock are of internal diameters of one inch  (1”), one and a half inches (11/2”), two inches (2”)and three inches (3”).

The working components of these impact gun sprinklers require high pressure withstanding components like couplings and water pipes. This is because the most gun sprinklers operate at pressures of 40 psi to 120 psi which are considered to be high pressures.

Rain gun sprinkler installation

Rain gun sprinkler installation requires pipes of high operating nominal pressure of 8 bars and above. This is to avoid the rapture or breakages of the pipe.

Commonly pipes that are used are that   with high wear and tear resistance, resistant to weather conditions, high resistance to pressure, high resistance against voltage cracking, durable, corrosion resistance, easy and reliable, reduced friction losses  and lower flow noise

Normally the rain gun sprinklers have outside threaded ends thus needed the reducing couplings to make it joined to the main line.

Specifications of Rain gun available at Eunidrip Irrigation Shop

We stock various rain gun sprinklers that work under high pressures and low pressures. The low pressure rain gun sprinklers are for the small farm application like an acre while the high pressure sprinklers are normally used on large farms like four acres onward.

For efficiency on operations, most rain guns are accompanied by double nozzles that helps to break the water jets close the rain gun tripod however, the smaller nozzles placed at the top of the gun normally performs this task of water breaking

The table below shows the rain gun application in terms of diameter throw and the water discharge per hour (irrigation kings website)

Size of the rain gun(inches)	Wetting diameter(meters)	Water discharge(meter cubic per hour)
1.0	20	6-7
1.5	30	10
2.0	40	18
2.5	50	25

 Uses of impact rain gun sprinkler

Rain gun sprinklers are normally used on plants/crops that are not affected by the fungal diseases like Anthracnose; Botrytis rots; Downy mildews; Fusarium rots; Powdery mildews; Rusts; Rhizoctonia rots; Sclerotinia rots; Sclerotium rots which are brought about by excess water on the leaves or dumbness

Impact gun sprinklers are normally applied in irrigating pastures, tall bushes orchards and maize plantations of large acreage. This is because of their water usage and radius of throw which covers large distances within a single rotation.

 Application areas for rain gun

• Forestry for seedlings and mature trees
• Pasture crop like Lucerne, Rhode
• Herbs mint, lemongrass, chives
• Hedge plants. kei apple, bougainvillea
•  Horticulture such as cabbage, spinach and kales
• Broad acre crops. wheat, barley, canola, sugarcane and corn/ maize
• Fruit orchards. citrus (orange, tangerine, and lemon), avocado, macadamia, paw paw, guava, mango, tree tomato, and passion

The working components of these impact gun sprinklers require high pressure withstanding components like couplings and water pipes. This is because the most gun sprinklers operate at pressures of 40 psi to 120 psi which are considered to be high pressures.

   Rain gun sprinkler installation

Rain gun sprinkler installation requires pipes of high operating nominal pressure of 8 bars and above. This is to avoid the rapture or breakages of the pipe.

Commonly pipes that are used for the rain gun installation posses the following characteristics:

• High wear and tear resistance
• Resistant to weather conditions
• Resistance to pressure
• Voltage cracking resistance
• Durable
• Corrosion resistance,
• Easy and reliable,
• Reduced friction losses and lower flow noise

Normally the rain gun sprinklers have inside threaded ends enabling them to be effectively joined or coupled with other reducing couplings to make it compatible to the main line.

   Components of rain gun sprinklers

 

• Rain gun sprinkler steel tripod stand-use to hold the sprinkler upright and majority made of steel
• Pumping unit .i.e. normally a booster pump for small rain guns and water pumps for bigger rain guns
• Conveying pipes- also known as delivery pipes. These pipes may include polyvinyl chloride pipes (PVC), high density polyethylene pipes (Hdpe) and polypropylene random pipes (ppr) with pressure rating of at least 8 nominal (PN8) since rain guns operates at high pressures.
•  Filtration unit. Commonly used filtration unit is the use of screen filters to eliminate the debris from getting into mainlines which in turn can cause the blockages of the rain gun nozzles.

Rain gun irrigation design and installation

On the installation and design of the rain gun, the irrigation designer must understand the working pressure and the flow rate of the gun, plant water requirement per irrigation cycle, type of the plant, climatic conditions and the topography or the slope of the farm.

After considering these factors, proceed with the pump sizing. Pump sizing is the process of matching the pump water pressure and flow rate to that of the rain gun against a gradient to ensure the wanted quantity of water is discharged at the designated region.

Impact rain gun installation continuation

Pump sizing is the mother of all design of rain gun sprinklers since the pressure from the pump is what will exert pressure in the water to rotate the gun.

When sizing the water pump, first consider the head of the gun. Let’s say the gun has a head of 30 meters or 40 meters which is the normal working pressure of most guns with the working flow rate of 25 cubic meter per hour the water pump size one will require will be at least twice times the head of the gun (30mx2=60) and twice the water flow rate of the gun (40 cubic meter per hour).

After sizing of the water pump then proceed to rain gun installation. For installation of the gun, one will need, delivery pipe, pipe fittings e.g. tees, elbows and adapters of the required sizes, hacksaw and the blades, safety gears  and any other tool and good sound of mind hehehe

1. Connect the rain gun head to the tripod stand and ensure the stand is firm enough to avoid toppling when the gun is rotating
2. Attach a PVC, HDPE, or delivery pipe to the rain gun sprinkler inlet at the base. At this point consider the threads. From the thread positioning either internally or externally one is able to choose the pipe to gun adapter

• Adjust the water gun sprinkler to the desired angle of irrigation water delivery. This is done by adjusting clips below the gun head.

1. Start your irrigation water pump at 20 starting /hour then adjust the throttle with time.
2. Walk along the delivery pipes to the gun point to check for any leakages because leakages reduce the pressure of the water pumps therefore, resulting into lower efficiency.

The differences between rain gun and the sprinklers

1. Rain gun is a large area covering Sprinkler generally replacing 8 to 15 sprinklers as per the model chosen and thus reducing labor requirement to great extent in shifting the sprinklers in the farm area.
2. Rain gun also gives choice to use as full or partial circle rotation with droplet size management mechanism for optimum working under windy conditions
3. Turbine drive model are gear driven wherein its rotation speed is unaffected by changes in wind velocity and thus offering highest uniformity of rain all over the area and hence are more costly.
4. They are best under windy conditions at site, and preferred for high precision sprinkling.
5. Rain gun is suitable for most high crops like fodder, maize, vegetables like Onions, carrots, grains and, pulses, plantation crops such as coffee, tea, cardamom, sugarcane etc.,
6. An average a rain gun can irrigate nearly 1⁄2 acre per position in about 1.5 to 2.5 pumping hours depending on the soil type, season and crop being irrigated.
7. Minimum pump head requirement is 5 HP high pump set head (giving 30meters to 35 meters head) if water is very near to ground level to run the rain gun.

    Advantages of rain gun sprinkler

1. Highly energy efficient, Long lasting and trouble free
2. Since the jet sprinkles over a large area, it avoids the setting up a large number of smaller jets.
3. Reduces labor cost, because the pipeline within the estate is minimized so also the number of jets.
4. The precipitation varies with the nozzle size, but unlike conventional jets, overlapping is not necessary.
5. This reduces the time required for irrigation as well as the savings on diesel.
6. Time is the essence in Robusta sprinkling and in the eventuality of an insufficient natural rain, more are can be covered with the help of these jets.
7. The jets are rugged and only require periodic greasing. Ease of installation, assembly and maintenance
8. The trajectory of the throw of water is such that the damage to pepper vines is negligible.
9. Part circle adjustments, saves water from going into neighboring plantations.

 Disadvantages of rain gun sprinkler

1. The rain gun and the raiser pipes are very heavy.
2. High day time temperatures result in evaporation loss.