The frictional line loss due to a 1-inch line exceeds the maximum operating pressure of most AODD pumps (120 psi / 8.3 bar). To calculate the TDH of the entire system, both the total static head and the discharge frictional line loss must be determined. For pump longevity, AODD users should strive to design systems that operate in the mid-range of the pump’s capabilities. If the air inlet pressure exceeds the system’s TDH, then fluid can be transferred in the pump system. To meet the desired flow rate, the suction line diameter may have to be increased to 2 inches, which will reduce the suction line loss to within the operating capabilities of the AODD pump.ī) Can the pump overcome the system’s total dynamic head (TDH)? In practical terms, this means the pump cannot operate in systems where suction line loss exceeds 6.5 psi / 0.45 bar. It is not uncommon to increase the diameter of the suction line to overcome suction line loss.Ī typical 1-inch AODD may have dry lift capabilities of 4.6 m / 15 ft of water or 6.5 psi / 0.45 bar. Pipe diameter and flow rate impact line loss greatly. To determine if the pump can draw in the process fluid, it is necessary to calculate the suction line loss for the desired flow rate. In other words, check whether the pump’s dry-lift capability exceeds the suction line loss at the desired flow rate. For example, when considering using a 1-inch AODD pump to transfer high-viscosity fluid, three questions are relevant:Ī) Can the pump draw fluid at the desired flow rate through the suction line?Īn approximate answer can be found by comparing the pump’s dry-lift rating to the suction line loss. Also important is the piping system to which the pump is connected. However, this is only part of the answer. Neoprene, stainless steel and PTFE ball checks have the highest specific gravity, or weight, allowing ball checks to seat reliably through high-viscosity fluids.
A rule of thumb is the denser the fluid, the heavier the ball check. If the ball is too light, it will hang up in the slurry and will not seat, leading to poor pump performance that includes viscosity issues and cavitation. A 30% slurry, on the other hand, has a higher viscosity and therefore requires a heavier ball to move through the slurry so the ball seats properly. Only to reduce noise, one should work with a soft seat and hard ball configuration or vice versa.
If a low-viscosity fluid is being transferred, the weight of the ball is not of critical importance because the fluid is not restrictive during the ball seating process. Understanding how this weight relates to the fluid has an influence on the material specified. Each of these materials has a different weight, or specific gravity. Ball checks come in a whole range of metal and elastomer configurations. Fluid density is an important factor to consider because diaphragm pumps utilize ball checks that rise and fall as pressure changes occur within the fluid chambers of the pump.