GB2103958A - Nozzle units - Google Patents

Abstract

A nozzle unit for producing an air stream comprises a body portion 10 defining a rectangular opening in which is located a rectangular body 13 to define a pair of outlets 14. The opening communicates with an air inlet 12 and air in use flowing through the outlets 14 flows over inclined surfaces 16 and then declined surfaces 18 of slightly concave form. Air from the surroundings is entrained with the air flowing over the surfaces, and quiet operation results. <IMAGE>

Description

SPECIFICATION Nozzle units This invention relates to nozzle units for producing an airstream, the nozzle units having an inlet for connection in use to a compressed air source.

Such nozzle units are widely used in manufacturing industry for such tasks as assisting or effecting the ejection of a component from a press tool, and cooling or drying components. It is desirable that the nozzle unit should be as efficient as possible but since the nozzle unit is likely to be used in a situation where human operators are present, it should also be as quiet as possible.

The object of the present invention is to provide a nozzle unit in a simple and convenient form.

According to the invention a nozzle unit of the kind specified comprises a body portion having a substantially rectangular opening which communicates with said inlet, a rectangular body supported in said opening so as to define upper and lower transverse outlets, said body downtream of said outlets presenting to the air flowing in use through the outlets first inclined surfaces which extend to relatively sharp transversely extending edges respectively, and from said edges second declining surfaces, the air flowing through said outlets flowing over said surfaces and entraining air from the surroundings to produce the air stream.

An example of a nozzle unit in accordance with the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a sectional side elevation of the unit, Figure 2 is a plan view of the unit and Figure 3 is an end view, The nozzle unit comprises a body portion 10 which defines an inlet chamber 11 in which in the example is secured an inlet union 12 which in use is connected to a compressed air supply. The body portion 10 defines a rectangular opening in which is located a rectangular body 1 3 and which with the opening defines upper and lower transverse outlets 14 through which air from the inlet chamber can flow. The surfaces 1 2A of the body 10 decline towards the outlets.

The rectangular body 1 3 extends to the sides of the opening and also to the exterior where it forms a deflector body 1 5. The deflector body downstream of the outlets 14 defines first inclined surfaces 1 6 on the upper and lower portions of the body and which extend to relatively sharp edges 1 7 respectively. From the edges 1 7 the body defines declining surfaces 1 8 which terminate in a substantially flat end 1 9. Conveniently the surfaces 16 are flat whilst the surfaces 18 are slightly dished so that the edges 1 7 which when viewed in plan, are convex to the outlets 14.

In use, air flowing through the outlets 14 flows over the respective surfaces 1 6 and 1 8 and by virtue of the Coanda effect, surrounding air is entrained to produce an airstream having the required directional properties. The angles of the surfaces 1 2A and 1 8 relative to the horizontal axis is not particularly important; however, the angles of the surfaces 1 6 relative to the horizontal axis and the size of the outlets 14 are important for maximum performance with minimum noise. The angle of inclination of the surfaces 16 should be between 12 and 270 with the optimum value lying between 20 and 220.If the angle is reduced the amount of entrained air is reduced and if the angle is increased the air leaving the outlets tends to separate from the body. The angle of the surfaces 18 is less whilst the fact that the surfaces 1 8 are dished helps to prevent spreading of the resultant air stream so that an increased thrust is obtained over a small area at a given distance from the nozzle unit. The outlets 14 should have a width between 0.125 and 0.25 millimetres with the optimum width being between 0.175 and 0.2. If the width of the outlets is increased above the upper quoted limit the noise generated increases whilst if the width is decreased below the lower quoted limit the thrust is reduced.

The sharp edges 17 are also important since it is found that the performance is improved as compared with a nozzle unit in which there is a smooth transition between the surfaces 1 6 and 18.

1. A nozzle unit for producing an air stream comprising a body portion having a substantially rectangular opening, an inlet in communication with said opening for connection in use to a source of compressed air, a rectangular body supported in said opening so as to define upper and lower transverse outlets, said body downstream of said outlets presenting to the air flowing in use through the outlets first inclined surfaces which extend to relatively sharp transversely extending edges respectively, and from said edges second declining surfaces, the air flowing through said outlets flowing over said surfaces and entraining air from the surroundings to produce the air stream.

2. A nozzle unit according to Claim 1 in which said second declining surfaces are dished.

3. A nozzle unit according to Claim 1 or Claim 2 in which the angle of inclination of said first surfaces lies between 120 and 270.

4. A nozzle unit according to Claim 1 or Claim 2 in which the angle of inclination of said first surfaces lies between 200 and 220.

5. A nozzle unit according to Claim 3 in which the width of said openings is between 0.125 and 0.25 millimetres.

6. A nozzle unit according to Claim 4 in which the width of said openings is between 0.175 and 0.2 millimetres.

7. A nozzle unit according to Claim 1 in which

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Nozzle units This invention relates to nozzle units for producing an airstream, the nozzle units having an inlet for connection in use to a compressed air source. Such nozzle units are widely used in manufacturing industry for such tasks as assisting or effecting the ejection of a component from a press tool, and cooling or drying components. It is desirable that the nozzle unit should be as efficient as possible but since the nozzle unit is likely to be used in a situation where human operators are present, it should also be as quiet as possible. The object of the present invention is to provide a nozzle unit in a simple and convenient form. According to the invention a nozzle unit of the kind specified comprises a body portion having a substantially rectangular opening which communicates with said inlet, a rectangular body supported in said opening so as to define upper and lower transverse outlets, said body downtream of said outlets presenting to the air flowing in use through the outlets first inclined surfaces which extend to relatively sharp transversely extending edges respectively, and from said edges second declining surfaces, the air flowing through said outlets flowing over said surfaces and entraining air from the surroundings to produce the air stream. An example of a nozzle unit in accordance with the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a sectional side elevation of the unit, Figure 2 is a plan view of the unit and Figure 3 is an end view, The nozzle unit comprises a body portion 10 which defines an inlet chamber 11 in which in the example is secured an inlet union 12 which in use is connected to a compressed air supply. The body portion 10 defines a rectangular opening in which is located a rectangular body 1 3 and which with the opening defines upper and lower transverse outlets 14 through which air from the inlet chamber can flow. The surfaces 1 2A of the body 10 decline towards the outlets. The rectangular body 1 3 extends to the sides of the opening and also to the exterior where it forms a deflector body 1 5. The deflector body downstream of the outlets 14 defines first inclined surfaces 1 6 on the upper and lower portions of the body and which extend to relatively sharp edges 1 7 respectively. From the edges 1 7 the body defines declining surfaces 1 8 which terminate in a substantially flat end 1 9. Conveniently the surfaces 16 are flat whilst the surfaces 18 are slightly dished so that the edges 1 7 which when viewed in plan, are convex to the outlets 14. In use, air flowing through the outlets 14 flows over the respective surfaces 1 6 and 1 8 and by virtue of the Coanda effect, surrounding air is entrained to produce an airstream having the required directional properties. The angles of the surfaces 1 2A and 1 8 relative to the horizontal axis is not particularly important; however, the angles of the surfaces 1 6 relative to the horizontal axis and the size of the outlets 14 are important for maximum performance with minimum noise. The angle of inclination of the surfaces 16 should be between 12 and 270 with the optimum value lying between 20 and 220.If the angle is reduced the amount of entrained air is reduced and if the angle is increased the air leaving the outlets tends to separate from the body. The angle of the surfaces 18 is less whilst the fact that the surfaces 1 8 are dished helps to prevent spreading of the resultant air stream so that an increased thrust is obtained over a small area at a given distance from the nozzle unit. The outlets 14 should have a width between 0.125 and 0.25 millimetres with the optimum width being between 0.175 and 0.2. If the width of the outlets is increased above the upper quoted limit the noise generated increases whilst if the width is decreased below the lower quoted limit the thrust is reduced. The sharp edges 17 are also important since it is found that the performance is improved as compared with a nozzle unit in which there is a smooth transition between the surfaces 1 6 and 18. CLAIMS

1. A nozzle unit for producing an air stream comprising a body portion having a substantially rectangular opening, an inlet in communication with said opening for connection in use to a source of compressed air, a rectangular body supported in said opening so as to define upper and lower transverse outlets, said body downstream of said outlets presenting to the air flowing in use through the outlets first inclined surfaces which extend to relatively sharp transversely extending edges respectively, and from said edges second declining surfaces, the air flowing through said outlets flowing over said surfaces and entraining air from the surroundings to produce the air stream.

2. A nozzle unit according to Claim 1 in which said second declining surfaces are dished.

3. A nozzle unit according to Claim 1 or Claim 2 in which the angle of inclination of said first surfaces lies between 120 and 270.

4. A nozzle unit according to Claim 1 or Claim 2 in which the angle of inclination of said first surfaces lies between 200 and 220.

5. A nozzle unit according to Claim 3 in which the width of said openings is between 0.125 and 0.25 millimetres.

6. A nozzle unit according to Claim 4 in which the width of said openings is between 0.175 and 0.2 millimetres.

7. A nozzle unit according to Claim 1 in which said body portion has surfaces which decline towards said outlets.

8. A nozzle unit for producing an air stream comprising the combination and arrangement of parts substantially as hereinbefore described with reference to the accompanying drawings.