WaStop Headloss
The Problem
To move a given volume of liquid through a pipe requires a certain amount of energy. An energy or pressure difference must exist to cause the liquid to move. A portion of that energy is lost to the resistance to flow. This resistance to flow is called head loss due to friction. Estimating head loss for a system, it’s usually divided in losses for the pipe itself called Major losses and losses in pipe fitting and valves etc. called Minor losses. It is important to minimize the loss of energy to avoid upstream flooding. During periods of high rainfall there is a significant need to evacuate water as quickly as possible to avoid ponding and flooding on streets, car parks or other areas.
The Solution
WaStop achieves the lowest headloss on the market by having a smooth ridged housing, a membrane with low co-efficient and a flexible membrane that adapts to the amount of water moving through the valve. Low headloss decreases the risk of upstream flooding caused by resistance in the system.
Headloss Importance
Low Headloss – Why Is It Important
WaStop has the lowest headloss amongst similar valves on the market. Low headloss decreases the risk of upstream flooding caused by resistance in the system. A pipe system operates on differential pressure. A higher upstream pressure relative to downstream, enables flow in the right direction. An increase in resistance increases the collection of water upstream. All systems contain losses due to resistance, but the aim is usually to minimize the losses to enable maximum flow through the system. When a restriction occurs, there is an accumulation of water upstream that can cause flooding. During the design phase of a storm water system the losses are considered. Anything added to the system after the original design has been made will change these dynamics. Therefore, it is desirable to keep the additional resistance of any part added to the system to a minimum. Using the WaStop check valve will introduce a small restriction to the system, but the additional head loss is minimal compared to other check valves available. Below we have a collection of information and films about head loss from both WaStop and other check valves.
Head loss through WaStop is lower than other check valves due to the following:
- Thin valve body
- Smooth valve body
- Smooth membrane material
- Flexible membrane which takes the shape of the water
If you want to move something, there will be resistance. If you try to push a heavy box along the ground, it will require a certain amount of effort to do it. Since the weight and the size of the box will not change, the work required should be the same regardless of the surface it is resting on. However, the box will be much easier to move on a smooth linoleum floor than trying to move it on a deep pile carpet. The difference in the required effort is due to friction. The carpet has a higher resistance to the movement of the box than the smooth floor.
To move a given volume of liquid through a pipe requires a certain amount of energy. An energy or pressure difference must exist to cause the liquid to move. A portion of that energy is lost to the resistance to flow. This resistance to flow is called head loss due to friction. Estimating head loss for a system, it’s usually divided in losses for the pipe itself called Major losses and losses in pipe fitting and valves etc. Minor losses. Learn more about minor losses through valves in our webinar - even though they are called minor losses they can sometimes be fairly substantial.
To learn more about headloss in general, and in relation to check valves in stormwater or sewer systems please download our webinar and whitepaper.
Headloss Tests
Low Headloss – Utah State Tests
Utah State University was contracted by Wapro to perform flow tests at the Utah Water Research Laboratory (UWRL) in Logan, Utah on 4 different sizes of WaStop check valves manufactured by Wapro. A coldwater test was performed to determine the discharge coefficient (Cv) for the valves at nine different flow rates.
The methodology and results are compiled in the documents below. These tests have been performed on standard membranes. WaStop can be fitted with different durometers of membrane material along with different types of elastomers depending upon the demand and application. This alters the open pressure, closing pressure and headloss. Contact Wapro for more information.
Headloss Competitors
Low Headloss Competitor Analysis
Differences between similar looking valves can be hard to understand just by looking with the naked eye. To help visualize the difference Wapro contracted Utah State University to perform a flow test on other inline check valves available on the market (competitor X). One particular valve was chosen due to the fact that to the untrained eye it can be deemed ’similar’ to WaStop. Wapro’s goal was to find out the difference between WaStop’s headloss and Competitor X headloss based on the same test scenario.
A coldwater test was performed to determine the discharge coefficient (Cv) for the valves at nine different flow rates..
The results, are compiled in the documents below, show the headloss for Competitor X, and the differences in headloss between WaStop and Competitor X.
- Competitor X DN200 (NPS 12") Headloss Testing
- WaStop vs Duckbill Headloss Tests DN750
Headloss User Experience
Customer Experience
Testing and proving a function works as intended doesn't replace the need to hear other like-minded people discussing the issues and solutions. Wapro's customers are the ones who really know if a particular functions works as intended or not. Below you'll find a few of the testimonials we have collected from customers. You can also read some of our case studies to see where WaStop has been used and the results of the projects.
