Spray nozzles & systems

What is the function of the spray nozzle and the spray process?

The first step when choosing the right spray nozzle is to define the function and application of the spray process, such as cooling a gas, washing a tank or flushing a conveyor belt. Type of spray nozzle, thus also spray pattern and droplet size, are important to consider in order to optimise the spray process.

Cooling product and objects BETE Knowledge Bank

 

Under Solutions our website lists a number of common applications and processes, as well as the nozzles that are recommended.

 

The full-cone nozzle creates a spray shaped like a cone and is the most common type of nozzle used in industry. There are three different types of full-cone nozzles - axial and tangential nozzles, and spiral nozzles.

Full cone nozzles

The most common type of spray nozzle used in industry is the full cone spray nozzle. Applications include gas cooling, gas scrubbing, demister flushing, absorption, liquid distribution and fire protection.

There are three different types of full cone nozzles - axial, tangential and spiral nozzles. Compared with the spiral nozzle, the axial and tangential nozzle creates relatively larger droplets with a very even fluid distribution within the cone and across the surface, compared to the spiral nozzle. Axial and tangential full cone nozzles have a higher volume flow in the outer part of the cone and an even, lower flow within the cone. The spiral nozzle produces multiple concentric cones. These cones form two to three bands of relatively coarse droplets iwth higher flow, surrounded by wider bands of relatively fine droplets and lower flow.

Spiral nozzle full cone. The spray pattern is created by the liquid cutting along the spiral, forming several concentric cones.

Spiral full cone nozzle

  • The spray pattern of the spiral nozzle is formed by the fluid shearing along with the turns of the spiral, which produce multiple concentric cones.
  • The cones form 2 to 3 bands of relatively large droplets, surrounded by wider bands of relatively small droplets. 

Axial full-cone nozzle creates a spray shaped like a cone. The incoming and outgoing spray directions are on the same axis.

Axial full-console nozzle

  • Spray exits on the same axis it enters
  • Internal disc or vane causes the liquid to spin, and the centrifugal force exerted upon the geometry of the exit creates the spray pattern.
  • Even distribution of droplets in the cone and across the surface
  • Wide range of flow rates
  • Large free passage

Tangential full-cone nozzle creates a spray shaped like a cone. The outgoing spray direction is 90° in relation to the input axis.

Tangential full cone nozzle

  • Spray exits 90° from the entry axis
  • Internal geometry creates the spray pattern by the liquid swirling around the body cavity before exiting the orifice
  • Even distribution of droplets in the cone and across the surface
  • Large free passage

The hollow cone nozzle creates a cone-shaped spray with a concentration of droplets in the outer part of the spray shaped like a ring. There are three different types of hollow cone nozzles - axial and tangential nozzles, and spiral nozzles.

Hollow cone nozzles

Hollow cone nozzles create relatively smaller droplets compared to full cone nozzles, which can be useful in for example gas cooling processes.

There are three different types of hollow cone nozzles - axial, tangential and spiral nozzles.

Spiral spray hole cone. The spray pattern is created by the liquid cutting along the spiral, forming a concentric cone with the spray concentrated to the outer part of the ring.

Spiral hollow cone nozzle

  • The spray pattern is created by the liquid shearing along the spiral, forming a concentric cone.
  • The spray is concentrated to the perimeter of the spray cone, which consists of relatively large droplets, whilst a fine mist is created within the cone.

Axial hollow cone nozzle creates a cone-shaped spray where the spray is concentrated to the outer part of the cone. Inlet and outlet spray direction are on the same axis.

Axial hollow cone nozzle

  • Spray exits on the same axis it enters
  • Internal disc or vane causes the liquid to spin, and the centrifugal force exerted upon the geometry of the exit creates the spray pattern.
  • Spray is concentrated on outer edges of the cone.
  • Relatively small droplets compared to axial full cone nozzles.
  • Large free passage

Tangential hollow cone nozzle creates a cone-shaped spray where the spray is concentrated on the outer part of the cone and forms a ring. The outgoing spray is 90° in relation to the input axis.

Tangential hollow cone nozzle

  • Spray exits 90° from the entry axis
  • Internal geometry creates the spray pattern by the liquid swirling around the body cavity before exiting the orifice.
  • Spray is concentrated on outer edges of the cone.
  • Relatively small droplets compared to tangential full cone nozzles.
  • Large free passage

The flat fan nozzle produces a spray that is shaped like a straight line. The droplets of the flat fan nozzle are relatively large compared to other nozzles and the spray is often compact and powerful.

Flat fan nozzles

Flat fan nozzles often create a high impact spray, with droplets that are relatively larger compared to other spray nozzles.

The flat fan nozzle is very effective for various flushing, rinsing and washing processes, but is also used to spray liquid over products and materials on conveyor belts.

Axial flat jet nozzle creates a spray that tapers towards the outer edges of the spray.

Axial flat fan nozzle

  • Uniform distribution with tapered edges

Deflector flat fan nozzle creates a spray with extra wide spray angle.

Deflector flat fan nozzle

  • The spray is deflected off an external surface and creates an extra-wide fan spray pattern

Misting and fogging nozzles create a spray consisting of very small droplets even at low pressures and are used for dust control, humidification, cooling, surface treatment, and for spraying oil mist.

Misting nozzles

Misting and fogging nozzles create a spray consisting of very small droplets even at low pressures and are used for dust control, humidification, cooling, surface treatment, and for spraying oil mist.

The higher the pressure, the smaller the droplets. Droplet size for misting nozzles ranges from 20 to 500 microns. Small droplets are ideal when full evaporation is required. It is important to note that the outlet opening is very small, which means that the nozzle can clog if the liquid contains solid particles. In order to prevent clogging, installing a pre-filter or using a misting nozzle with a built-in filter is recommended.

The mist nozzle forces the liquid through a small outlet hole, which atomises the liquid into very small droplets, creating a mist.

Small opening

  • Liquid is atomised by being forced through a very small opening
  • Narrower spray pattern at lower pressures

A mist nozzle with a small pin at the outlet hole. This type of fog nozzle atomises, i.e. atomises, the liquid when the laminar jet hits the pin at the outlet hole, thus creating a fine mist.

Impingement

  • Liquid is atomised into a fine mist or fog when the laminar jet impinges on the pin.
  • Spray angle 70° - 90°

Air atomising nozzles create a spray by mixing air with the liquid in the spraying process, thus creating relatively smaller droplets compared to other nozzles. The spray pattern is available as full cone, hollow cone, and flat jet.

Air atomising nozzles

Air atomising nozzles create a very fine spray of small droplets and are used for cooling, humidification, lubrication, surface treatment, etc.

The spray is created by mixing air with liquid in the spray process, thus creating relatively smaller droplets compared to other spray nozzles. The spray pattern is available as full cone, hollow cone, and flat fan.

This product group consists of a range of components, which can be combined in different ways to create the right drop size and flow for a particular application. Air atomising nozzles are also the best solution if you have a high viscosity fluid, where a 'regular' nozzle is undable to create small enough droplets.

Air atomising nozzle with internal mixing. Liquid and air are mixed inside the nozzle and leave the nozzle through the same outlet hole.

Internal mixing

  • Liquid and air are mixed in the nozzle and exit the nozzle through the same orifice.
  • The streams are not independent; airflow changes will affect the liquid flow
  • Not suitable for liquids with a viscosity above 200 cP.

Air atomising nozzle with external mixing. Air and liquid leave the nozzle through two separate orifice holes.

External mixing

  • Air and liquid exit the nozzle through two separate orifices.
  • Air and liquid flow rates can be controlled independently, allowing precise metering of the liquid flow rate
  • Suitable for all types of liquids, even above 200 cP.

Intermittent spray nozzles control spray and dosage using electric or pneumatic control.

Automatic nozzles

Spray nozzles and systems for intermittent spraying of liquids are used, for example, in the food industry and the pharmaceutical industry when high precision dosing is required or when a very expensive spray medium is used and spillage is to be avoided. The spray and dosage are controlled by means of electrical or pneumatic controls.

Pulse Width Modulation (PWM)

BETE's FlexFlow™ Spray Control System creates optimal spray precision by regulating the spray flow using Pulse Width Modulation (PWM). With traditional spray nozzles, the flow is adjusted by changing the fluid pressure, which in turn leads to a change in droplet size and spray pattern. PWM flow control creates a cyclical spray, i.e. on and off, up to 150 times per second. FlexFlow™ controls the fluid flow, with unchanged spray characteristics, without requiring a change in fluid pressure, creating a uniform, high-precision spray.

BETE's FlexFlow™ Spray Control System creates optimum spray precision by regulating the spray flow using Pulse Width Modulation (PWM). PMW flow control creates a cyclical spray, i.e. on and off, up to 150 times per second.

To clean tanks and vessels efficiently, different types of tank cleaning nozzles are used - static tank cleaning nozzles, rotating tank cleaning nozzles and larger tank cleaning machines,

Tank cleaning nozzles

Spray pattern of tank cleaning nozzles ranges from 90° to 360° depending on the shape of the tank and the purpose of the tank cleaning. Different tank cleaning nozzles create different droplet sizes, which will affect cleaning impact.