COMPONENTS OF IRRIGATION SYSTEMS

Emitters

Click icon to add pictureThis may include popup sprinklers, micro emitters, drip emitters, swivel emitters, gear driven emitters or impact driven emitters.

Depending on the design specifications, size, and landscape conditions, there could up to 20 or more emitters in any one system.

PVC PIPE

PVC pipe: this is available in various sizes and class categories from 20mm up to 200mm. Most pipes are six metres in length (generally).PVC pipe is an integral part of the irrigation system and supplies (carries) water to all of the various parts of the system: be it valves or emitters.

There could be up to 30 or more PVC pipes in a standard irrigation system

PVC FITTINGS

PVC fittings are used to join PVC pipes together.They are available in many different sizes and configurations and specific purpose PVC fittings are also available if required.

When installing a system most fittings are slip joint fittings and require priming fluid and PVC cement to enable joining.

Low Density (LD) pipe (commonly known as poly pipe)

for domestic purposes LD pipe is available in 13mm, 19mm and 25mm sizes. It is available in various lengths from 25 metres to 200 metre rolls.

It is important not to exceed the manufacturers' specifications when using LD pipe as most applications are for small garden beds only with either micro sprays or drip irrigation.

Low Density (LD) fittings (commonly known as poly fittings)

These are the most common fittings available at specialised irrigation shops, department stores and most hardware outlets. They come in a range of different sizes and configurations to suit individual applications.

LD fittings must always be secured with suitable clamps so that the LD pipes do not break apart.

Electric valves (also known as solenoids)

Electric valves are available in a range of sizes and are commonly used to automatically control the water sent to various outlets.

25mm threaded valves are often used for domestic purposes and offer the benefits of size and price. Sometimes they have large water flow paths depending on the models. Always check manufacturers specifications for further information

Master valves

Master valves are required to ensure that at the end of the watering cycle the water is turned off at a central valve, which is normally located close to the water meter.This ensures that: 1)The water in the rest of the system is at rest and not under pressure.

2) If, for some reason (e.g. faulty fittings/components, damage, or faulty workmanship), there is a leak in the irrigation system, the mains water will not leak continuously into the ground and be wasted.

Electrical wiring

Most control units transmit 24 Volt current to the solenoid via copper wire which is available in many colours and gauges.Generally, for domestic purposes 0.5mm multi-strand wire is used rather than single core. Single core is not as flexible and can break easily.

A run of 0.5mm gauge controller wire should not exceed 100m as electrical conductivity is reduced.

Control unit

'Control units are used to set and control the amount of time that an emitter is on or off.A control panel is used to set the:1)days to be watered

2)time to be watered

3)watering duration.

Most control units offer these basic features and more.

Manual valves

Manual valves in a domestic irrigation system are usually of a gate valve type or a ball valve type.Manual valves are required to ensure that the maintenance of the system can be carried out with the water turned off. It is also used for throttling the amount of water passing through the system.

There are many manual valves to suit the various density and size pipes the market place has to offer.

Rain sensors

: rain sensors are devices that can be set to predetermined water application rates so that over-watering does not occur.

These simple devices collect water when it rains and in turn, expand small leather washers. These temporarily disconnect the electricity to the control unit.

A N E W WAY T O WAT E R L A N D S C A P E S I S T O U S E D R I P I R R I G AT I O N . D R I P F E D I R R I G AT I O N H A S M A N Y A D VA N T A G E S :

1. I T I S M O R E E F F E C T I V E T H A N A S T A N D A R D I R R I G AT I O N S Y S T E M B E C A U S E T H E R E I S N O WAT E R L O S T T H R O U G H E VA P O R AT I O N A S T H E I R R I G AT I O N

S Y S T E M I S B E L O W G R O U N D .

2. C O N S E Q U E N T LY, D R I P I R R I G AT I O N I S WAT E R S AV I N G A S L E S S WAT E R I S U S E D T O I R R I G AT E L A R G E R A R E A S .

3. T H E R E I S R E D U C E D VA N D A L I S M A S A L L O F T H E I R R I G AT I O N C O M P O N E N T S A R E B E L O W G R O U N D .

4. W E E D G R O W T H I S R E D U C E D .

5. T H E S Y S T E M O N LY R E Q U I R E S L O W P R E S S U R E T O O P E R AT E .

6. T H E R E A R E A R E D U C E D N U M B E R O F C O N T R O L VA LV E S .

7. I N S T A L L I N G D R I P I R R I G AT I O N I S R E L AT I V E LY E A S Y.

A D O M E S T I C D R I P I R R I G AT I O N S Y S T E M M AY C O N T A I N   O N E O R M O R E   O F T H E F O L L O W I N G C O M P O N E N T S :

Drip irrigation

Tech filters

These filters have Teflon Injected Cartridges that deliver small amounts of a herbicide to the root zone of the plant.

This prevents root intrusion into the drip line.

Pressure devices

pressure devices are used to stabilise or maintain pressures within the drip irrigation

Inline drip tube

an inline drip tube contains drippers which are built into the irrigation tube and are incorporated during the manufacturing process.Drippers have evolved in their design and are now very technically advanced. They include measured watering rates from 1 litre to 20 litres per hour.These inline drippers are often placed at equal distances and come in various diameter low-density poly pipe.

Drippers of this nature can be compensated or non-compensated

Ground water sensors

These sensors use a series of probes that are placed in the ground where the best results may be obtained. They automatically monitor the amount of water in the soil and in turn control the water delivered to the area.

They are very useful for saving water.

Air release valves

Air release valves are incorporated into drip irrigation systems to release air trapped within the system.If this air is not allowed to escape quickly it may impair the delivery of water to the irrigation system and can contribute to the reduced life of the system.

Like most other products, air release valves come in a range of sizes.

Flushing valves

These clever units allow the system to flush and remove any debris which has not been captured by the main filter at the start of a watering cycle.

They ensure that the system lasts longer and is not damaged

W H E N I N S TA L L I N G C O M M E R C I A L O R I N D U S T R I A L I R R I G AT I O N S Y S T E M S Y O U W I L L

U S E T H E S A M E E Q U I P M E N T A S C O N TA I N E D I N A D O M E S T I C S Y S T E M B U T Y O U M AY A L S O I N C L U D E

T H E F O L L O W I N G :

Commercial / Industrial systems

Large pumping equipment

Large irrigation projects rely on pumps that draw water from a source such as a dam, lake or underground body of water.1)Large pumps are used for two main reasons:larger quantities of water

may be obtained from these water sources thus increasing the number of emitters which can be used in an irrigation area.

2)The water taken from these sources is usually of low grade quality and therefore suitable for irrigation purposes, without putting a strain on drinking supplies.

Pressure and flow monitoring equipment

May include high and low pressure cut out switches and flow monitoring devices.This type of equipment is usually found on expensive golf courses, parks and gardens where system integrity is crucial.

Monitoring equipment can be linked to many other devices that control pumps and sensors or fill water tanks. Any equipment that is useful in streamlining the irrigation process. This may include an array of electrical voltage stabilisers, relay switching gear and electrical management systems.

Large pipes

Given that large volumes of water are drawn from the water sources mentioned above, large diameter pipes are required to transport the water to the various parts of the irrigation system.

Pumping station sub stations

Sometimes there is a requirement on especially large projects or installations, to have secondary pump stations acting as a booster to ensure water is carried the required distance and the required operating pressure is maintained.

An example of this is where water is required to first fill a holding tank that fills over a few days at a slow pace. This water is then pumped through a secondary pump to its required areas.

Satellite controllers

: Satellite controllers are used by large organisations such as shires to monitor irrigation systems remotely

O T H E R I R R I G AT I O N S Y S T E M S M AY I N C L U D E A G R I C U LT U R A L S Y S T E M S U S E D I N V I N E YA R D S ,

N U R S E R I E S A N D G R E E N H O U S E S .

T H E S E S Y S T E M S M AY U T I L I S E A L L O F T H E E Q U I P M E N T M E N T I O N E D A B O V E I N T H E D O M E S T I C O R C O M M E R C I A L

S Y S T E M S , B U T M AY A L S O I N C L U D E T H E F O L L O W I N G P I E C E S O F E Q U I P M E N T

Other systems

Upside down emitters/Emitters

These are often used in greenhouses. Almost all green houses that are used to propagate plants require some form of watering from above to maintain the humidity of the greenhouses and aid the moisture being made available to the plants.

There are a large range of emitters available with all sorts of specifications to suit almost every type of situation and condition.

Filters

Filters are used to remove debris from large or small irrigation systems. They may be banks of automated filtering systems that are used in almost all irrigation projects, especially in the nursery industry.Sprinkler emitters are prone to clogging from fertilisers, dirt and sand, which occurs when they are transported through the irrigation system. That's why filters are so important and necessary.Generally there are four types of filters available:Screen Filter

Disk Filter

Sand Filter

Valves

These are used to control the flow of water. There are various types of valves ranging from manual, electric and special purpose valves, which are used in the horticulture/irrigation industry.Different sizes and flow rates are required with the large watering variation that exists in these industries.

These could include flow control valves, gate valves, ball valves, butterfly valves, taps, plastic, brass and steel constructed water control devices.

Pumps

: there are a range of various pumps used in agriculture today including:• small chemical

injection pumps

submersible pumps

centrifugal pumps

fertigation pumps and

chlorinators.

Fertigation systems

These may be incorporated into irrigation systems to help deliver fertiliser to irrigated areas.

As there is a large variety of equipment available further information may be obtained from individual manufacturers.

Timers

a water timing device ranging from simple clock timers to computer scheduling programs are incorporated in many irrigated situations.

Weather stations

Some applications may require the use of weather station units to help control the watering schedule.

These stations monitor rainfall, humidity and wind conditions. Some controllers have built in weather stations that can be programmed to adjust the watering cycle to the weather conditions.

PRESENTATION PREPARED BY CARLOS HOLDER

WITH PERMISSION FROM J IRAHLEE BOTANTICAL GARDENS

THE END