Pulse Width Modulation (PWM) Enables Flow Rate Control Without Changing Spray Pressure

Benefits

• Flexibility: Achieve a wide range of flow rates with a single nozzle
• Immediate flow adjustments: Using AutoJet spray controllers, response time of electrically-actuated PulsaJet spray nozzles is almost instantaneous
• Reduced clogging: Maintain low flows even with large spray orifices for improved reliability and reduced maintenance
• Reduced misting: Low flow operation using larger orifices at low pressures reduces the misting common at higher pressures and improves transfer efficiency and safety
• Uniform coating/improved quality: Constant pressure operation prevents variations in spray angle and drop size for more even coating over a wide range of flow rates

PWM Food Processing

Examples of PWM Flow Control Applications in Food Processing:

• Spraying flavors or oils onto bread, pastries and rice cakes
• Surface coloring with egg coating, milk protein, or caramel
• Moistening dough with water to maintain proper consistency
• Misting bread with water to improve seed adhesion
• Spraying food ingredients onto products or into trays
• Spraying water on hamburger patties, vegetables and pizza prior to freezing to maintain proper weight
• Spraying antimicrobial agents onto meat & poultry for food safety
• Spraying sunflower oil on peanuts
• Spraying aroma onto coffee and other food products

What You Need for PWM Flow Control

A fast spray nozzle
Electrically-actuated PulsaJet nozzles achieve speeds up to 10,000 cycles per minute and are ideal for PWM flow control. PulsaJet nozzles also offer accurate spray placement, excellent spray pattern integrity and a choice of hydraulic or air atomizing spray tips.

A spray controller–plus software
AutoJet Technologies offers a wide range of spray control options for manual or automated PWM flow control
regulation. Basic versions offer PulsaJet nozzle control with manual flow adjustment and advanced versions
provide total automation, optional spray detection/verification and more.

Spray knowledge
Effective PWM flow control requires a strong knowledge of how liquids flow and how spray nozzles work. Turning a spray nozzle on and off very quickly is not enough.

Spraying Systems Co. is the global leader in spray technology. Spray nozzles, turnkey spray systems, custom fabrication and research/testing services comprise the company’s offering. Spraying Systems Co. has ten manufacturing centers and more than 90 sales offices around the world. More information is available at www.spray.co.za or by contacting the company directly on +27 11 6183860 or grant@monitorspray.co.za

Monitor Engineering based in Johannesburg, sole importers of Spraying Systems Co’s range of spray nozzles, spray controllers and custom spray systems has opened an office in Durban  and will no longer  soley be working through agents in the KZN region. Due to the changing nature of the company’s extensive product range from supplying just spray nozzles to sophisticated precision spraying equipment, the company feels that expert application assistance and product knowledge is required to assist customers in this region – specifically with the Autojet and Spray Analysis range of products. Autojet Technologies is the turnkey systems division of Spraying Systems Co. and supplies a  range of patented spray controllers and top quality spray products, high speed automatic spray guns ,spray lances and manifolds that are engineered for precision spraying ,saving chemicals and water , minimizing manual labour and improving product quality.

Our Spray Analysis division operates the industry’s most sophisticated spray research laboratory. We have the ability to conduct Computational Fluid Dynamics(CFD) ,proof of concept tests, quality control tests, and design prototypes for new product development.

Monitor Engineering has represented Spraying Systems Co. in Southern Africa for over 45 years, supplying spray solutions to industries like food and beverage, pharmaceutical, automotive, chemical, petro-chemical, refinery ,paper, steel, mining and general manufacturing. Our product range includes standard spray nozzles, tank wash and air nozzles, air knife blower packages, lubrication systems, heated systems for spraying viscous liquids like chocolate, custom made spray injectors and Quills for Refinery applications and shower nozzles and headers for the Pulp & Paper industry and a variety of other standard spray products. Our tank wash range of products has expanded so rapidly over that last 6 months that we felt the need to have a dedicated website just for the tankwash market, www.tank-cleaning.co.za

Spraying Systems Co. is the global leader in spray technology. It has the broadest product range in the industry, ten manufacturing facilities and sales offices in more than 85 countries. Spray nozzles, turnkey spray systems, custom fabrication and research/testing services comprise the 70-year-old company’s offerings.

For more information visit www.spray.co.za or contact us on grant@monitorspray.co.za

At the heart of all spray operations in your mill, is the spray nozzle. It is the component that determines performance in moisturizing, cleaning, lubricating, edge trimming, bleaching, knock-off, gluing and dozens of other applications . Worn nozzles can raise water consumption drastically.

The cost of using nozzles worn by only 15% in your mill can increase by thousands of Rands.

At Spraying Systems Co we have developed 6 strategies to help you save water, chemicals and energy in your mill.

Flow

Centrifugal pumps: Monitor the readings of your flow meter to check for increases in flow.
Use a calibration vessel to measure the flow of a nozzle for a specific time at a specific pressure.
Compare the readings with the manufacturers catalogue or compare them with the same tests conducted on a new nozzle.

Positive displacement pumps: In applications using positive displacement pumps, which provide the same capacity regardless of pressure, the spraying pressure will decrease as the nozzle orifice enlarges. Lower spray velocities and spray impact will result.

Pressure at showers and nozzles

Centrifugal pumps: Monitor for increases in volumes of liquid sprayed. The pressure of the spray could decrease.

Positive displacement pumps: Monitor gauges to detect any drop in pressure and reduction on the impact on surfaces sprayed. The volume of the sprayed liquid may remain the same. Also monitor for any increases in pressure which could be caused by blocked nozzles.

Drop sizes

As nozzle orifices wear, the liquid flow increases or the spraying pressure drops, resulting in larger drop sizes. Larger drops result in less total liquid surface area.
Actual drop size

Impact

Check for premature wear of the felt or any other related problems. In applications with centrifugal-type pumps, impact may actually increase because of the increased flow through the nozzle.

Spray Pattern

Visually inspect the spray pattern to detect any changes in uniformity.
Streaks and heavier flows in the centre of the pattern, accompanied by a decrease in the effective spray angle coverage typify deterioration.
Measure the width of the spray over the surface sprayed.
If the nozzle wears gradually, you may not be able to detect any changes until a significant increase of flow is evident.

Spray patterns of both tips show little difference. Spray collection in tubes gives dramatic evidence of 15% increase in capacity.

Contact us for complementary paper machine and nozzle audits in your plant and for a copy of our new paper catalogue.

WindJet Air Knives powered by energy-efficient regenerative blowers provide excellent performance in drying and blow-off operations and eliminate the need for costly compressed air. Operating costs can be reduced by as much as 95 percent when the packages are used in a wide range of operations including debris and dust blow-off, removal of excess water and moving products.

WindJet Air Knives feature a unique 1/8″ leading edge along the length of the knife to direct a consistent and controlled air stream that retains its integrity further downstream and eliminates spotting and blotching. The air stream produced by the knives entrains ambient air to increase the total volume of air and maximize drying and blow-off efficiency.

Unlike other blower types, the regenerative blowers included with the packages are rugged, reliable and require infrequent, minimal maintenance. Plus, no sound enclosure is needed because the blowers provide low noise operation. Each air knife package is customized for the application. Air knives are available in lengths from 6” to 36” and two air slot sizes, .040” and .060”. Regenerative blower assemblies are available from 5.5 to 30 HP. Packages include pressure relief valve, pressure gauge, air inlet filter, filter monitoring gauge, vibration dampener, fittings and mounting adapter.

Spraying Systems Co. is the global leader in spray technology. Spray nozzles, turnkey spray systems, custom fabrication and research/testing services comprise the company’s offering. Spraying Systems Co. has ten manufacturing centers and more than 90 sales offices around the world. More information is available from your local office.

Pulp and Paper Industry Catalog, 66A, has just been published by Spraying Systems Co. This 108-page catalog includes detailed information, including performance data, on a wide range of showers and spray nozzles widely used by paper mills around the world.

In addition to product information, the catalog includes a technical reference section and specification guidelines to help users select the best products for specific applications. Another section addresses spray optimization and provides tips to ensure trouble-free operation once equipment is installed.

Showers, shower nozzles, web trimming nozzles, air atomizing and automatic nozzles, black liquor nozzles, stock chest cleaning equipment, air nozzles and air knife packages are just a few of the product lines included in the catalog.

Pulp and Paper Industry Catalog can be requested or downloaded at www.spray.com/papermaking

Spraying Systems Co. is the global leader in spray technology. It has the broadest product range in the industry, ten manufacturing facilities and sales offices in more than 85 countries. Spray nozzles, turnkey spray systems, custom fabrication and research/testing services comprise the 70-year-old company’s offering.. More information is available at http://www.spray.co.za or by contacting the company directly at grant@monitorspray.co.za or +2711 6183860.

Our AutoJet® Lubrication Systems provide a highly efficient method of applying lubricants and corrosion protection fluids on bands (coils) and blanks as well as wire or other type of materials in pressing and stamping operations.

Reducing production costs and operating efficiently are important considerations. So is finding the right lubrication system. As the world leader in spray technology, we can help you find the system for your process.

The L210 AutoJet Lubrication System is designed for low-viscosity solutions and is typically used with hydraulic spray nozzles.

The Type P400 System is used in processes with high-viscosity lubricants up to 600 centistokes (mm2/sec) being sprayed with air-atomized spray nozzles, the unique features of the systems ensure that you will not run any risk of polluting or creating any oil mist.

Features & Benefits

• Exact metering of the lubricant guarantees absolute repeatability:
  L210: precise indexing of pumps
  P400: precise air pressure control
• Optimum distribution of the lubricating fluid on the coil (top, bottom, both sides)
• Easy to maintain due to pneumatic lifting cylinders
• Quick and easy assembly
• No misting or pollution of the work environment
• Optional installation of additional nozzles for spot lubrication of critical points
• Solenoid valves direct the return flow of different lubricants to the proper container
• Surplus amounts of lubrication oil remain in the coil lubricator and are returned to the supply container
• Containers are non-pressurized and can be filled during operation
• Effective full-flow filters guarantee that no contaminants are allowed to enter the pump or the nozzles
• Easy change-over between various lubricants

If tank cleaning in your facility involves filling and draining or manual cleaning, there’s an unneces-sary profit leak in your plant. There are dozens of ways to automate cleaning of tanks of all sizes and all of them will significantly reduce:

• Cleaning time
• Manual labor
• Water, chemical and energy use
• Wastewater disposal costs

Tanks will be cleaner and returned to service more quickly enabling increases in production time. Operating costs will be lower and profits will be higher.

Savings of $50,000 per tank aren’t uncommon. Most plants have multiple tanks, so it is easy to see how automating cleaning of multiple tanks can save hundreds of thousands of dollars per year by reducing operating costs and increasing production time.

Selecting the right automated tank cleaning product primarily depends on:

• Tank size
• Level of impact required to remove the residue in the tank
• The chemicals used for cleaning and the temperature of the cleaning liquid

Options include spray balls, stationary tank cleaning nozzles, high-impact fluid-driven units, motorized tank cleaners and fully automated tank cleaning systems. Ask your tank clean¬ing equipment supplier for a no-obligation on-site evaluation to determine which solution is best for your application and to provide a pay-back analysis. The evaluation is usually free and is an efficient way to get the automation process started.

If variations in your spray operations affect the quality of your product or process, you can reduce your operating costs by adding a spray controller. Adding spray control usually yields these benefits:

• Reduced use of costly chemicals, water and energy
• Reduced manual operation and monitoring, freeing workers for other tasks
• Reduced maintenance time by minimizing or eliminating overspray and misting
• Reduced scrap through improvements in quality
• Reduced downtime for set-up and batch changes

There are many spray control options available:

• Fluid delivery systems that include standard pump and motor sets provide can optimize the performance of a wide range of nozzles including tank cleaning nozzles
• Basic spray controllers provide precise on/off liquid and air control for automatic spray nozzles
• More sophisticated controllers provide advanced timing control to optimize the performance of automatic spray nozzles, electronically monitor pre-set spray variables in real-time and offer advanced fault monitoring to alert operators to problems. Some can be pre-programmed to monitor and automatically adjust spray performance based on process variables such as conveyor speed, temperature and batch control
• Fully automated systems are available for advanced spray operations such as gas cooling, lubrication, panel board spraying, antimicrobial application, coating with viscous fluids and more.

Reductions in operating costs will obviously depend on your spray application and the level of spray control selected. Often, the cost of adding spray control or a fully automated system can be recouped in just a few months.

Here are just a few examples of how manufacturers are using spray control to lower operating costs:

Meat processors are applying precise doses of antimicrobials onto meat and/or into packaging prior to vacuum sealing. A spray controller uses a trigger signal from an indexing conveyor to activate the spray. Chemical consumption is dramatically reduced without compromising food safety.

Bakery and snack food manufacturers coat conveyors with grease to prevent products from sticking to the belts. Instead of pouring grease on the conveyors, a simple automated system is used to pull grease directly from a container and coat the conveyor uniformly without any waste or mess. Considerably less grease is used and downtime for maintenance to clean up the excess lubricant is eliminated.

Manufacturers of engineered wood products use automated spray systems to apply release agents to boards and conveyors during processing to prevent boards from sticking to belts, variations in board thickness and bursting. The even application of the release agent has resulted in scrap reduction by as much as 95% and release agent consumption has been cut by at least 50%

Enclosing nozzles in a header or manifold is a simple, cost-effective way to minimize maintenance downtime and extend nozzle life.

If you’ve ever struggled with connecting air and liquid lines or been faced with a tangled mess of tubes, you will immediately understand the value manifolds can bring to your operation. Set-up and maintenance time can go from hours to minutes and result in increases in production time. Downtime due to performance problems caused by bends or kinks in the tubing is eliminated and the added protection of the man¬ifold keeps nozzles operating at peak efficiency longer.

There are many types of manifolds readily available:

• Channel manifold: Basic spray nozzle manifold incorpo¬rated in a C-channel for easy mounting and maintenance
• Pipe-in-pipe manifold: Conventional spray manifold mounted inside a slotted pipe to protect nozzles from the external environment. Nozzles and tubing are enclosed in the manifold
• Modular manifold: Lightweight and easy-to-assemble, this manifold keeps tubing organized
• Compact manifold: Service nozzles while keeping tubing in place with lightweight, compact manifolds

Manifolds are available for both hydraulic atomizing and air atomizing nozzles. The cost for standard manifolds is typically low and easily recouped.

Installing spray manifolds above and below conveyors can save hours of labour and thousands of litres of water and cleaning chemicals. Automating conveyor cleaning also enables workers to be deployed to other projects.

Manifolds are typically equipped with flat spray nozzles to cut through debris and sticky build-up. Nozzles are positioned to ensure cleaning of the entire belt width and edges. Full cone nozzles with extra large free passage are often used to minimize clogging when recirculated water is used for cleaning. A basic spray controller can be used for precise on/off control, activate cleaning cycles based on pre-determined schedules and ensure nozzles are only spraying when needed.

The specifics of your application will determine how much you can save by automating conveyor cleaning, but most processors report water and chemical reductions in the 50 to 60% range.

When was the last time you checked your spray nozzles or took the time to measure the capacity?

If the answer is “never” or “I don’t remember”, you may be surprised at how much that oversight may be costing. Using nozzles that are spraying just 15% over the rated capacity could be adding almost $200,000 per year to your operating costs.

A quick look at your nozzles will only reveal obvious problems such as clogging, corrosion or damage. Wear of the nozzle orifice isn’t visible but it can be very costly. Here’s just one example:

Nozzles spraying 15% over capacity; total system flow of 379 l/min:

The cost of increased electricity or pump wear is not in¬cluded in this example. Water is estimated at $2.75 per gallon; chemicals at $1.00 per gallon with a 10:1 dilution ratio and the system is in operation 2,080 hours per year. This is a conser¬vative estimate and is based on one spray system.

Most plants have many spraying operations so $182,800 in waste could easily become $500,000 or $1,000,000 if multiple systems are in use.

You can prevent this waste from occurring. Measuring flow rate is a quick and easy process and well worth the small effort required.

If you are using centrifugal pumps:

• Monitor flow meter readings to detect increases. Or, collect and measure the spray from the nozzle for a given period of time at a specific pressure
• Then, compare these readings to the flow rates in the manufacturer’s catalog

If you are using positive displacement pumps:

• Monitor the liquid line pressure for decreases. The flow rate will remain consistent

The cost to replace nozzles is usually far less than continuing to use worn nozzles. It is recommended that you do a simple analysis like the one above, determine the cost to replace nozzles and pre-determine a replacement interval. Most us¬ers elect nozzle replacement when nozzles are spraying 10 to 15% over capacity.

Paper highlights:

• A detailed look at the difference between dust prevention and dust suppression and how to determine which strategy is right for you
• What you need to know about matching liquid drop size to dust particle size and what happens when there is a mismatch
• Tips on choosing the correct nozzles for optimal dust control

Paper highlights:

• How nozzles wear and the impact of worn nozzles on water, chemical and energy use, wastewater costs, pump life and product quality
• How to detect nozzle wear when it isnÕt visible
• Steps you can take to extend spray nozzle life
• How to develop a proactive nozzle inspection/maintenance program

Paper highlights:

• The costly consequences of clogging in spray operations
• An in-depth look at the most common causes of clogging
• Three ways to detect clogging instantly
• Seven approaches to minimizing or eliminating clogging

Paper highlights:

• Five reasons why you should reduce compressed air use in addition to the cost-savings
• Three options for reducing your compressed air use by 25 to 90% and how to determine the feasibility of these approaches in your operations
• How to eliminate the use of compressed air completely

Paper highlights:

• The primary causes of water waste in spray operations
• How to calculate the true cost of water waste in your applications .
• Specific steps you can take to maintain nozzles for optimum performance .
• Water-saving alternatives to open hoses for manual cleaning and sanitation.

Paper highlights:

• How to shore up cleaning operations to minimize waste and reduce cleaning time.
• The role headers and manifolds play in spray system operational efficiency and how using the right header can ensure optimal performance and significantly reduce maintenance time
• A look at the benefits of spray system automation and the quick payback of spray control.
• Case studies documenting the savings realized by other manufacturers.

Eliminate open hoses for clean-up and sanitation. Use spray guns instead.

Did you know that you can reduce water consumption by as much as 50% by using low-pressure spray guns instead of open hoses? Ensuring that water is “on” only when needed can cut water use in half. It’s a small change that can yield big savings.

Here is just one example:
A food processor was using 15 open hoses for sanitation. The hoses were in use eight hours per day, five days per week, 50 weeks per year. 1,892 kiloliters of water were used daily.

Using hoses equipped with spray guns, water use decreased by 30% per hose. Water use dropped 65,411 litres by per day.

The processor saved $30,240 annually on water and disposal costs. The cost of the spray guns was recouped after approximately 30 days of use.

See our Spray Guns page for more information.