Environmental Benefits of Automated Systems from BARSTONE IRRIGATION SYSTEM

Simplicity: Saves time and effort. Proper hand watering is a part time job. It's also messy, inaccurate and wasteful. In most cases hand watering is not a feasible option. Once an automatic irrigation system is installed you never have to drag a hose around the yard, never have to figure out if you have applied enough or too much water.

Efficiency: Water is a precious resource and conserving it is everyone's' responsibility. With a custom-designed irrigation system from BARSTONE IRRIGATION SYSTEMS, each area of your landscape will be fitted with the proper water-saving sprinklers, a controller that will turn the system on (only when needed) and off automatically and on a precise schedule, resulting in the most efficient use of water.

Value: Attractive landscaping requires precise water management. An automatic irrigation system will protect your landscape investment by assuring healthier, longer living plants and turf. In addition, installing a system is a convenience upgrade that will measurably increase your property's appraised value and aesthetic appeal.

Beautiful landscaping increases aesthetic appeal as well as your property's value. In order to maintain this investment, regular and precise watering is essential. Environmental Irrigation Systems will provide you with an efficient and affordable solution to your landscape needs.



PUMP FACTS

Pump selection depends on two main criteria? Yes, once the type of pump has been selected for your application, i.e. borehole, centrifugal, piston etc, the size of the pump is critical. Every pump has a ‘pump duty’, and this will affect your pocket one way or another.

Pump duty is simply how much water the pump is required to deliver, and to what pressure, or ‘head’, as it is commonly referred to in pump jargon. Every pump is tested by the manufacturer and comes with a pump curve. The pump curve tells us all about the pump performance capabilities. It tells us the following important data. There are many irrigation and water engineers/technicians throughout the country who understand pumping systems. Unfortunately, there are many more unqualified persons in these industries, for one reason or another, who don’t understand pumps and the parameters in which they operate. Often, in the pursuit of saving a few rands, a customer purchases equipment unsuitable for his application, which costs him far more in the long run.

Here are the basics to pump systems.

Capacity

Together with head (see below), this determines the size of pump required. It is the delivery of the pump in litres per second, litres per minute or litres per hour, shown on the X-axis of the curve. Generally, we would aim to select a delivery that is close to the maximum efficiency point of the pump for the reasons mentioned below (see efficiency).

Efficiency

This is the curve on the graph showing us at which point the pump performs at its best efficiency. This guides us when selecting the size pump for the required duty, and has a direct impact on the cost of running the pump. Over a few years, a pump operating at a low efficiency will cost you a lot more than the saving you may have made by buying the cheaper one. Also, a pump running outside of its efficiency parameters can create many costly managerial and operational problems during its lifetime.

Head

This is the pressure that the pump delivers the liquid to, measured in metres (head) or kPa (kilopascals), and shown on the Y-axis of the pump curve. 100kPA is equal to a column of ten (10) metres of water. The required head will dictate at what speed the pump must operate at and the number of stages required to deliver the pressure.

NPSH

This refers to what is known as the Nett Positive Suction Head. This dynamic is probably the least understood factor in pump systems, and causes the most problems. When a pump is situated above the level of a body of water from which it is pumping, the water has to be lifted. This is known as the suction lift. Contrary to popular belief, pumps do not suck water from their supply in this instance. What in effect takes place, is that the pump creates a vacuum in the impeller housing and suction pipe, and water is lifted into that vacuum chamber as a direct result of atmospheric pressure being applied on the body of water, be it a dam, river or reservoir. At sea level, the positive suction head is close to ten metres absolute, and the NPSH of the pump guides us as to how far we can safely site the eye of the impeller before we start running into undesirable pump problems. With altitude, this positive suction head diminishes, and a pump practitioner needs to take cognisance of this factor when selecting a pump. Not taking this factor into account will create what is known as cavitation. This is the phenomenon whereby the liquid begins to sheer, creating bubbles that has just about the same effect as sand going through the pump, and sounds like it too, reducing impeller and shaft life enormously. A poorly designed and fitting suction system which allows air to get into the suction line also causes cavitation. Just about all pump problems emanate from improper suction design, pipes and fittings.

Power requirement

There is a direct relationship between the power required to deliver water, the head and efficiency of the pump. The flow rate has the most influence on required power (kW and amps). In the absence of making a power calculation, the pump curve also specifies the power (kW) required at the pump shaft.

Speed

The curve tells us at what speed the pump needs to operate at to perform the necessary duty (flow and head). The faster the speed of the pump, the greater will be the flow and head capability. There is a limit to how fast a pump can run, however, and this relates to material stresses. The downside of running a pump too fast is generally increased maintenance and decreased efficiency. A wide range of flows and heads can be achieved by combining increased speeds and the addition of stages (impellers).

Barstone Irrigation Systems (Pty) Ltd specialises in designing and supplying irrigation systems and equipment for agriculture, recreation/sports, mines and industry. In the irrigation and water distribution industries, the pump is the heart of the system. However, suffice to say, it is only one component of the system as a whole. Generally, a technical representative from a pump manufacturer will be able to supply a pump if his customer is able to give him all the relevant information, like flow rate, head and available power. However, this is often not the case, and a customer ends up with unsuitable equipment for his application. The same applies to the pipeline and sprinklers. Our responsibility to our customers is to design an irrigation or water distribution system by evaluating the customers’ requirements, selecting the most appropriate equipment to do the duty and to ensure that all the components are compatible with one another.