Hydropneumatic Pumping in PLUMBER


One of the most used pumping systems in the water supply to buildings is the one that includes a hydropneumatic tank.

In this video you will see how PLUMBER offers all the necessary parameters so that you can select the pumping equipment to use when you opt for hydropneumatic pumping.

Transcription

In the case of supplying the buildings’ water supply networks using hydropneumatic systems, PLUMBER offers tools that will help you perform the calculation and selection quickly.

This project file corresponds to that of an auditorium made up of four water networks.

We have a main network, the floor level +1.80 m. In which two toilets are supplied to the north and south.

From this network, are supplied, through three interior risers the same number of networks located at the -1.8 levels.

And at the -1.53 level.

Let’s look the isometric view so you have a better idea of the distribution scheme.

We have the +1.8 Level Water Network

By clicking on this option, dependent networks are shown.

Here, those of the -1.8 levels.

And here, the -1.53 level.

Note that the network’s elevations, since they are formed by pipes that are below the finished floor, are lower than those of the corresponding floor level.

Well, to take care of these Water Networks, we have created in this project a riser plan.

In it, as you see, we have an underground tank, with a minimum suction level of -3 meters.

And a useful volume calculated from the water demand, in the order of 7000 liters.

This tank stores the water and serves as a suction tank to a pumping group. As we have seen in other videos.

The particularity in this case is that we have selected the type of Hydropneumatic Pumping in its properties.

Then enter the operating differential pressure, that is, the difference between start and stop of the pump.

As well as the unit in which we want to present the volume calculated for the pressure tank.

Since it is common to express it in gallons, it is the unit that we have specified here. But you can select the one that best suits your calculations.

Then, to select the pumping equipment that will feed the pressure tank, we have created two pumping pipes, each with a version, of a certain pump model.

Each version, as you will imagine by the name of the model, is associated with a rotational speed of the equipment, assuming that it is possible here to attend to the pump with a variable speed motor.

With this information, click OK to save the changes.

In this case, we are assuming that the pumping system as well as the top of the tank, are at elevation 0, so we have had to add here a vertical pipe that allows the rise to the network of the level +1.8.

And, another new addition in version 4: it is now possible to associate to the risers plan’s nodes, in addition to the typical risers, any water network supplied from a riser node.

That is why in this node, located at the level of the network of the level +1.8, we associate the corresponding water network.

With all this configured, we perform the calculation and design to be able to see results in the pumping group.

The first thing you’ll see in the results tab, when it comes to hydropneumatic pumping, is this box in the lower left.

In it we have the necessary parameters to be able to size the pressure tank.

You can choose to use the probable or simultaneous flow, calculated by the program in attention to the number and type of sanitary fixtures.

Or, if you prefer, enter the value of your preference by checking this box.

The number of pumping equipment’s starts per hour.

And the number of pumps feeding the pressure tank.

In this case, given the magnitude of the flow, we opted for a single pumping unit.

Thus, with the start and stop pressure values calculated from the differential pressure and clicking this button, you can obtain the total volume of the pressure tank which, for this example, is about 81 gallons.

Then, the most important part of all this: How do the pumps that we have pre-selected operate?

Note that the graph, in the form of resistance curves, will show you the position of the start and stop pressures with two horizontal lines.

The minimum operation point, calculated by the program to attend the project’s W.N’s, is shown here.

And, of course, in the Selection Values box above.

Then you will see the total head pumping curves for each pumping pipe or pumping equipment under analysis.

Of course, the intersection of these curves with the start and stop lines will tell you how the equipment is operating.

And this is what is summarized in the table at the top.

In the first line you can see the results for the model with 1100 revolutions per minute.

The values for stop and start pressures are presented, separated by the slash.

Thus, this equipment, would give between 4.41 and 6.84 liters per second when it is used to pump against the hydropneumatic tank.

Although, if we look at the efficiency values, we will have that, for the starting pressure, the deviation of the point from the pump’s BEP is very high.

And, in the case of the pumping pipe for the rotational speed of 900 rpm, we see that, since the pumping curve does not reach the position of the stop pressure, the initials of NOT AVAILABLE are shown instead of a value.

But we see that, at these revolutions, the pump would operate very well, in terms of efficiency, close to the starting pressure.

In any case, as you can see, with all this information you can easily try other models, at other speeds, to try to reach a selection of centrifugal pump for the hydropneumatic system.

So we hope that this and all the new features of PLUMBER, will be of great help to you in your plumbing systems projects.