7 Costly Causes of Nozzle Wear
Jon Barber
Maybe you’re thinking to yourself that the waste and inefficiency caused by using worn spray nozzles just can’t be all that significant. If so, it’s time to change your thinking and determine if nozzle wear is a problem in your operations. Like many other processors, you may discover that you are wasting millions of gallons of water, thousands of gallons of chemicals and incurring many other unnecessary costs due to using worn nozzles.
Once you appreciate the magnitude of the issue, you should be motivated to take immediate corrective action.
They may look simple enough, but spray nozzles are highly engineered precision components that can wear over time or suffer damage during normal operations or even cleaning. These are the most common problems that cause sub-standard spray performance:
Causes of Spray Nozzle Troubles
Erosion/wear
Gradual removal of metal causes the spray nozzle orifice and internal flow passages to enlarge and/or become distorted. As a result, flow usually increases, pressure may decrease, the spray pattern becomes irregular and liquid drops become larger.
Corrosion
Spray nozzle material can break down due to the chemical properties of the sprayed material or the environment. The effect is similar to that caused by erosion and wear, with possible additional damage to the outside surfaces of the spray nozzle.
High temperature
Certain liquids must be sprayed at elevated temperatures or in high-temperature environments. The spray nozzle may soften and break down unless special temperature-resistant materials are used.
Caking/bearding
Build-up of material on the inside, on the outer edges or near the orifice is caused by liquid evaporation. A layer of dried solids remains and obstructs the orifice or internal flow passages.
Accidental damage
Damage to a nozzle orifice can occur if a spray nozzle is dropped or scratched during installation, operation or cleaning.
Clogging
Unwanted solid particles can block the inside of the orifice. Flow is restricted and spray pattern uniformity disturbed.
Improper re-assembly
Some spray nozzles require careful re-assembly after cleaning to ensure that internal components, such as gaskets, O-rings and valves, are properly aligned. Improper re-assembly causes leaking and inefficient spray performance.
To identify worn nozzles, look for these clues:
Quality control issues and increased scrap
Worn, clogged and damaged spray nozzles will not perform per specification, and can result in uneven coating, cooling, cleaning, humidifying and drying.
Increased maintenance time
Unscheduled spray system downtime, or an increase in cleaning frequency, is an indicator of spray nozzle wear.
Flow rate change
The flow rate of a spray nozzle will increase as the surfaces of the orifice and/or the internal core begin to deteriorate. In applications using positive displacement pumps, the spraying pressure will decrease as the spray nozzle orifice enlarges. Even small changes in flow rate can have a negative impact on quality, so routine monitoring can reveal potential problems. But in some instances, the spray pattern will look fine — so it will be necessary to actually collect and measure the spray fluid output in order to reveal wear.
Deterioration of spray pattern quality
When orifice wear occurs in hollow cone spray nozzles, spray pattern uniformity is destroyed. Streaks develop and the pattern becomes heavy or light in the circular ring of fluid. In full cone spray nozzles, the pattern distribution typically deteriorates as more liquid flows into the center of the pattern. In flat fan sprays, streaks and heavier flows will be visible in the center of the pattern and the effective spray angle coverage will decrease.
Spray drop size increase
Liquid flow will increase, or spraying pressure will decrease, as nozzles wear. The result? Larger drops and less total liquid surface area. This is tough to detect visually, so if you suspect a problem, arrange for drop size testing.
Lowered spray impact
Worn spray nozzles operate at lower pressure, generally resulting in lower spray impact. (Ironically, in applications with centrifugal-type pumps, impact may actually increase because of increased flow through the spray nozzle.) Special testing may be required.
More from Jon Barber on Nozzle Wear.
Related Articles
The following charts will give you multiple pathways to assist when you are attempting to troubleshoot AC Motors. The 4 problems covered are: Problem A - Motor won't start or motor accelerates too slowly, Problem B - Motor runs noisy, Problem C - Motor overheats, Problem D - Motor bearings run hot or noisy
The following charts will give you multiple pathways to assist when you are attempting to troubleshoot AC Motors. The 4 problems covered are: Problem A - Motor won't start or motor accelerates too slowly, Problem B - Motor runs noisy, Problem C - Motor overheats, Problem D - Motor bearings run hot or noisy
See More
Open impellers are frequently used in centrifugal pumps which pump liquids that contain suspended solid materials (slurries, paper stock, etc). They do not plug as easily as closed impellers and usually have a simple external adjustment to maintain the correct impeller clearance as internal parts wear.
Open impellers are frequently used in centrifugal pumps which pump liquids that contain suspended solid materials (slurries, paper stock, etc). They do not plug as easily as closed impellers and usually have a simple external adjustment to maintain the correct impeller clearance as internal parts wear.
See More
One of the important ingredients for making and keeping a reliable electrical connection is clean contact surfaces. When initial contact is made between electrical contact surfaces, no matter how smooth and level the surfaces, only a few high points touch. As the contact force increases, more points make contact until at optimum force most of the metal-to-metal contact has been accomplished. Contact theory tells us that these points are actually cold welds.
One of the important ingredients for making and keeping a reliable electrical connection is clean contact surfaces. When initial contact is made between electrical contact surfaces, no matter how smooth and level the surfaces, only a few high points touch. As the contact force increases, more points make contact until at optimum force most of the metal-to-metal contact has been accomplished. Contact theory tells us that these points are actually cold welds.
See More
Nowadays most everyone has a powerful computer in their pocket, their phone. Many of us are using them in maintaining our plants. Whether you are neutral or a devotee of the iPhone or Android devices, I think it’s safe to say we have only just scratched the surface of possibilities for using our smartphones to maintain our plants. Just think about how good it is to always have a great camera in your pocket with pictures viewable instantly. Does anybody remember the hassle of film? Waiting days to find out if an image was captured and how well it looked.
Nowadays most everyone has a powerful computer in their pocket, their phone. Many of us are using them in maintaining our plants. Whether you are neutral or a devotee of the iPhone or Android devices, I think it’s safe to say we have only just scratched the surface of possibilities for using our smartphones to maintain our plants. Just think about how good it is to always have a great camera in your pocket with pictures viewable instantly. Does anybody remember the hassle of film? Waiting days to find out if an image was captured and how well it looked.
See More
Contrary to popular opinion, a centrifugal pump is not designed to develop one head at a single capacity as requested by the pump purchaser. In fact a pump is designed and produced to supply a whole range of head-capacity conditions as identified on it’s performance curve. The pump will operate on that curve if it is driven at the particular speed for which the curve is drawn.
Contrary to popular opinion, a centrifugal pump is not designed to develop one head at a single capacity as requested by the pump purchaser. In fact a pump is designed and produced to supply a whole range of head-capacity conditions as identified on it’s performance curve. The pump will operate on that curve if it is driven at the particular speed for which the curve is drawn.
See More
The development of the electric motor has given us the most efficient and effective means to do work known to man. The electric motor is a simple device in principle. It converts electric energy into mechanical energy. Over the years, electric motors have changed substantially in design, however the basic principles have remained the same. In this section of the Action Guide we will discuss these basic motor principles. We will discuss the phenomena of magnetism, AC current and basic motor operation.
The development of the electric motor has given us the most efficient and effective means to do work known to man. The electric motor is a simple device in principle. It converts electric energy into mechanical energy. Over the years, electric motors have changed substantially in design, however the basic principles have remained the same. In this section of the Action Guide we will discuss these basic motor principles. We will discuss the phenomena of magnetism, AC current and basic motor operation.
See More
There has always been a debate on whether jack screws should remain tight against the side of the machine case after the machine has been moved into position or to back off the screws, so they do not touch. Should jack screws be tight or backed off? The answer is yes and no. In some situations you should leave the bolts tight against the machine and in other situations, it may be better to back off the jack screws.
There has always been a debate on whether jack screws should remain tight against the side of the machine case after the machine has been moved into position or to back off the screws, so they do not touch. Should jack screws be tight or backed off? The answer is yes and no. In some situations you should leave the bolts tight against the machine and in other situations, it may be better to back off the jack screws.
See More
