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Low water hardness and low TDS (Total Dissolved Solids) are critical for proper cleaning and reduction of water spotting in car and truck wash applications. Water hardness is measured in grains of hardness. Typical drinking water can range from 100-250 grains of hardness. However, water hardness under 5 grains is usually best for the most efficient use of detergents or soaps in vehicle cleaning.

A water softener is usually required to get hardness down to zero grains which is necessary to, in turn, get TDS down to zero. The size of the softener required is a function of the quality of the incoming water, as well as, the gallons required in a typical day for a specific facility. Left untreated, high mineral content in a plumbing system can tremendously affect the efficiency of the plumbing system, as well as, reduce the life of pumps, valves, and other equipment.

TDS (Total Dissolved Solids) is the makeup of minerals, salts, metals, etc. that are present in a volume of water. This can include any inorganic element that is present in water other than pure (H20) water molecules. Typically TDS is measured in PPM, (Parts per million). The EPA allows up to 500 PPM for human consumption in water but vehicle washes need to be in the range of 0-50 PPM to rinse and dry without spotting.

Therefore; typical reverse osmosis, spot free rinse vehicle system will produce zero parts per million (PPM) of TDS when the filter/membranes in the system are new. Thin-film Composite or Cellulose Acetate membranes are designed to reduce zero grain water to zero TDS water. As membranes provide the filtering process over time, they will begin to plug or foul. The amount of time for this to occur depends on water usage and flow.

Typical testing will show TDS increasing, with spotting occurring about 40PPM. At this point, membranes should be replaced which will bring the TDS back to zero and the process begins again. Membrane material differs and is specifically designed for tap water, brackish water and seawater. Tap water membranes are used with typical city supplied water.

There are many simple devices available to test for water hardness and TDS to ensure your softeners, spot-free rinse system and filters are operating properly and efficiently. If you have further questions about reducing the amount of total dissolved solids in your business plumbing system give us a call at 1-888-677-5054 or visit us here. Take care!

Have you ever wondered how to quickly and accurately solve the problem of correctly sizing the horsepower for a pumping application? In this post we offer a short lesson in yet another technical application that our Sales Team deals with on a daily basis. We practice the principle of horsepower sizing almost every day at Dultmeier Sales.

In order to correctly size the horsepower for an application one must perform the following equation(s) in order to calculate. For positive displacement pumps we use the output pressure & flow rate required to determine the required horsepower. Centrifugal pump horsepower sizing is calculated using different methodology. We will elaborate on centrifugal pumps later in this post.

For positive displacement pumps, such as plunger, piston, diaphragm, or roller pumps we want to take the pressure (psi) x flow rate (gpm) divided by the constant for the particular type of pump, (which is based on the general efficiency of the pump type).

Determine the Type of Pump & Drive Option

For Piston and Plunger pumps, the constant factor is 1460. Roller pumps we use 1030. Lastly, Diaphragm pumps we use a factor of 1370. These constant factors are used for pumping water solutions - if we get heavier or more viscous solutions than water - our factors will need to be altered.

Centrifugal and Gear pumps can vary greatly and must be engineered to the specific application. That being said, we can look at some examples further down the line in this post.

We also need to consider the type of drive option that will be used. For instance, when using an electric motor versus a gas or diesel engine, there are varying drive constant factors, as well. More on this below in the post.

Horsepower Sizing Examples Explained

Example 1: Plunger pump rated flow is 4 gpm at 2000 psi. "EBH" or Electric Brake Horsepower required would be 4 x 2000 = 8000 divided by 1460 = 5.48. This equation shows us that we would require an electric motor with at least 5.48 horse power output to allow the pump to operate at peak performance. In this instance you would most likely need to use a 7-1/2 HP electric motor as most motor brands are generally 1HP, 1.5HP, 2HP, 3HP, 5HP, 7.5HP, 10HP, 15HP, 20HP, 25HP, etc.

It is important to note that electric motors have a rated horsepower and your specific application will have a required horsepower. Required specifies the horsepower needed to produce the desired output flow and pressure. While, rated horsepower defines the horsepower at which the motor is rated. For instance, if the application requires a 13 HP motor, one would need to select a motor that is rated for 15 HP (there is not an electric motor rated for 13 HP or 14 HP). Best practice is to select a motor that has a rated horsepower which exceeds your required application horsepower.

Example 2: Diaphragm pump rated flow is 12 gpm at 500 psi. The EBH would be calculated as such: 12 x 500 = 6000 divided by 1370 = 4.38 This would require an electric motor with at least 4.38 horsepower output to allow this pump to operate at peak performance.

Specialty Applications - Diesel Transfer Horse Power Sizing

For calculating gas or diesel engine horsepower requirements, a general rule is to take EBH required x 2.0. Example 1 above would require 5.48 EBH x 2. 0 = 10.96 engine horsepower requirement. Therefore you would need a gas or diesel engine that will develop at least 10.96 horsepower to allow the pump to operate at peak performance.

You can look at some diesel transfer units (centrifugal pump) that we have sized specifically for flow rates at the nozzle. We have multiple offerings that are designed to produce flow rates through a plumbing system. When calculating, we figure in the Total Dynamic Head of the plumbing system. In the case of our Diesel Transfer Skids, that means the pressure loss through the hose reel, 32ft of hose (inside diameter varies based upon specific unit) and a discharge nozzle. We use a self-priming centrifugal pump in these skid systems. When dealing with self-primer centrifugal pumps a safe efficiency factor to use is 50% efficiency.

When using gas or diesel engines to power pumps, depending on specific brands, "engine" horsepower requirements could be reduced slightly in some instances. For instance, some engines may have a higher compression or provide more torque as a result of enhance production practices. This is generally a smaller factor but something to consider when powering a pump with an engine.

Centrifugal Pump Horsepower Sizing

A major difference in sizing centrifugal pumps lies in the size, or trim, of the impeller. Based upon the solution, desired flow rates, and TDH in the plumbing system - we will size a pump to have a certain impeller trim and this directly correlates to the required horse power.

Generally speaking, we use pump curves to assist in sizing a centrifugal pump for a specific application. A pump will ALWAYS operate on it's curve. That's why it is vital to accurately determine our desired output flow rate, TDH, and solution being transferred. All of these factors, and actually many more like temperature and viscosity can, and will, affect the required horse power and impeller size of a centrifugal pump.

We have multiple tools at our disposal to assist with this process. One of them comes from a supplier of ours, Wilo. Dultmeier Sales' expertise paired with the expertise of Wilo helps us to provide a value-added service for our customers in pump/motor sizing for many applications.

Standard Efficient vs. Premium Efficient Electric Motors

Another important note to make is the difference between a standard efficient motor and a premium efficient motor. With the passing of Department of Energy regulations in January 2020 - many pumps (specifically straight centrifugal pumps) are now held to a certain degree of efficiency standards. The main goal being power consumption. Premium efficient motors are designed to be just that...much more efficient than a standard efficient motor.

Many pump manufacturers have since, or are in the process of switching, to premium efficient motors to assist in ensuring their pump products meet the mandated efficiency standards. Some manufacturers were able to re-engineer their pumps to meet the regulations - while others needed to redesign the pumps and upgrade to premium efficient motors.

Be aware, in some larger NEMA frame motors, the premium efficient option can boast a larger footprint. If your motor footprints do not match, this could cause an issue when you go to install the replacement motor. This is an important thing to consider when replacing standard efficient motors.

Service Factor in Electric Motors

Lastly, we want to consider the service factor in an electric motor of choice. A common service factor that many motor manufacturers use is 1.15. This means if your horsepower is rated to 20 HP then you actually have some leeway to go slightly beyond the rating - if necessary. 20 HP x 1.15 Service Factor = 23 HP. If our application had a required horsepower of 22.25 HP we could select this example motor with a service factor of 1.15.

While it's certainly not advised to select the example 20 HP motor in this instance - it could work. We would always caution on the side of error and advise the end user to select a rated 25 HP motor.

We certainly hope that this post provided useful content. As always, should you have any questions about pump sizing - don't hesitate to call us at 888-677-5054. Be good out there.