# Does the height of the water column on top of this pump matter?

• alingy1
In summary, the conversation discusses the use of a pump and special tube to measure strain, as well as the potential complications when moving the apparatus to a different location. The orientation of the water column is also addressed, with the suggestion to maintain the same head in all testing locations. Alternative solutions, such as simulating the water column or using a pre-pressurized vessel, are also mentioned. Ultimately, maintaining the same water height above the horizontal measuring tubes is crucial for accurate measurements.

#### alingy1

We are using the following pump to measure the strain on a special tube.
http://www.instechlabs.com/Support/manuals/HABP.pdf

This special tube is connected on each side to another tube that is connected to one of the two connectors on the pump. (The two connectors of the pump were put parallel to the floor, not like the picture where they are perpendicular.)

One of the tubes that connects the special tube to the pump has a tube attached to it with a column of water in it. We fill the column of water and we are able to put water through the whole system.

We reached a problem in our project: we need to redo the experiment in another setting across the city. So we will have to move the whole apparatus and redo our measurements.

Now, inevitably, the column of water won't be at its same place (it's just a flexible plastic tube that you hang on the ceiling and connects to the other special-tube-pump-connector tube). The column is hung on the ceiling and depending the tables we have there and where we can hang the tube on the ceiling, the column could be bent with an "s" shape or be more horizontal.

Because we want the strain to be the same between the first set of data and the second set of data obtained, does the orientation of the water column matter? I feel we are doomed... But I am no expert in fluid mechanics. Please help.

I think you've got it right. "Head" is the vertical distance from the measurement point to, in your case, the free surface of the liquid.
If you MUST have the same head, put the assembly on the floor, move to a room with a higher ceiling, move outdoors and string it up in a tree!

As a technical alternative, you could simulate your water column by terminating the tube in a pressure vessel with the appropriate pressure maintained by other means; or a pre-pressurized vessel large enough so the that volume difference from the pump flow is irrelevant.

Angling or S shaping the flexible tube will make no difference as long as the height of the water level is maintained at the same height above the horizontal measuring tubes. Your best practical approach would be to determine the minimum head clearance at all of your planned test locations and use the acceptable water height for the lowest head clearance location for all of your tests.

## 1. What is the purpose of the water column on top of a pump?

The water column on top of a pump serves as a buffer between the pump and the water source. It ensures that the pump is always primed and ready to pump water, preventing the pump from running dry and potentially causing damage.

## 2. How does the height of the water column affect the pump?

The height of the water column directly affects the amount of pressure that the pump needs to generate in order to pump water. The higher the water column, the more pressure is required, and the harder the pump needs to work.

## 3. Is there an ideal height for the water column on top of a pump?

Yes, there is an ideal height for the water column on top of a pump. This ideal height is typically determined by the manufacturer and can vary depending on the type and size of the pump. It is important to follow the manufacturer's guidelines to ensure optimal performance and prevent damage to the pump.

## 4. Can the height of the water column be adjusted?

Yes, the height of the water column can be adjusted by adding or removing water from the column. However, it is important to follow the manufacturer's guidelines and not exceed the maximum recommended height, as this can put unnecessary strain on the pump.

## 5. What happens if the water column is too low or too high?

If the water column is too low, the pump may not be able to generate enough pressure to pump water effectively. If the water column is too high, the pump may have to work harder, leading to increased wear and tear and potentially causing the pump to overheat. It is important to maintain the recommended water column height for optimal pump performance.