Sustainable Village Accumulator Tanks
Sustainable Village offers three models of accumulator tanks. They differ by their volumes, which in turn are appropriate for applications depending on the size of the garden, greenhouse, or facility. These tanks are used together with pumps to keep a constant pressure in a Blumat or other irrigation system. While the pumps are designed to operate intermittently, the accumulator tanks maintain pressure in irrigation systems when the pump is resting.
How They Work
These tanks are more than meet the eye. The interior of these pressure accumulator tanks feature an air bladder. This bladder envelops the actual water/nutrient solution (in a membrane) in the tank. When the pump/nutrient solution begin to lose pressure in the tubing following the tank, the pressurized air bladder squeezes down on the membrane of water/solution, maintaining pressure in the tubing. When the bladder reaches its limit, a pump (preceding the tank) will turn on and restore pressure both to the tank as well as irrigation tubing.
The accumulator tank is in essence a buffer, allowing the pump to turn off and rest without sacrificing pressure in the tubing. This allows for tubing (or irrigation line) with a constant pressure, which is exactly what Blumat Watering Systems need to work properly.
These tanks are included with the Basic Pump Kit. These pressure accumulator tanks are intended for gardens with smaller canopy-size and/or smaller. They can hold up to one quart are are manufactured by Shur-Flo.
They go by the following code on the Sustainable Village website: WP15688
The tank features 1/2″ NPT ports, and a working pressure of up to 125PSi.
These tanks are included with the High-Flow Pump Kit. They are intended for commercial-scale gardens or greenhouses, and can supply gardens with up to about 400-600 Blumat sensors. They hold 4 gallons of water or nutrient solution.
They go by the following code on the Sustainable Village website: WP16130
These tanks are included with the Ultra High-Flow Pump Kits. They are intended for commercial-scale gardens and multiple greenhouses or rooms in the same facility. They can also be used in the high-flow kits, and increase the lifespan of the pump.
They go by the following code on the Sustainable Village website: WP16907
These tanks feature a Schroeder valve. A pressure gauge can be used to check the pressure of the air bladder inside the tank. This should be beetween 5-10PSi, and should not exceed 10PSi. The tank can be manually charged using a bike pump up to roughly 7PSi, the preferred pressure if pressure is lost for some reason.
A standard pressure gauge can be used to get an accurate reading from the Schroeder valve.
Why are they Necessary in Blumat Systems?
Pressure accumulator tanks are necessary to use with Blumat systems, since tropf Blumat sensors require a constant and steady pressure. The initial calibration process for Blumat sensors calibrates the sensor to a certain pressure–if the pressure is increased, the flow rate will increase and the calibration won’t be accurate. The opposite occurs if the pressure is decreased–so a static pressure is ideal.
One might wonder–why can’t a pump simply be integrated that outputs a steady pressure?
Pumps can be configured to output a steady pressure–however, this is generally coupled with either a steady flow rate (this will not work with Blumat systems, because the flow rates are changing moment-to-moment). The other problem with pumps with a constant pressure output is that they generally require a rest time. All of the pumps featured in kits from Sustainable Village have a 2:1 Rest:Work ratio.
This means the pumps need to rest for two units of time for every single unit of time the pump is working. Blumat systems need a constant supply of water–so, we are at a conundrum! The pumps supply a constant pressure, but cannot do so 24/7.
This is why accumlator tanks are necessary with Blumat systems–they maintain a constant pressure in the irrigation tubing, even when the pump turns off. So as the pump is resting, the accumulator tank picks up the slack–the air bladder squeezes down on the membrane of water or nutrient solution, keeping adequate/constant pressure in the tubing, and giving the Blumat sensors water as they call for it. In essence, accumulator tanks are buffers between a pump and an irrigation system. They allow for a pump to turn off, while keeping pressure in the tubing and allowing for continuous flow. They are the perfect solution for integrating pumps with Blumat Watering Systems.