[0001] The invention relates to nozzles and has particular application to pumping apparatus
for mineral fibre at least when used as insulation, such a nozzle comprising a body
member that substantially reduces in cross-section between an input part of a first
constant cross-section and an exit part of a second constant cross-section.
[0002] We have experienced difficulties in achieving entirely satisfactory filling of cavity
walls with mineral fibre as insulation. We prefer to use mineral fibre, such as available
commercially as Rockwool, because of its high insulation value coupled with excellent
physical and chemical stability. Our preferred pumping apparatus, see our copending
British patent applications Nos. 81/08008 and 81/08009, is highly effective in producing
a smooth and regular stream of gas, usually air, with a substantially even entrainment
of mineral fibres. The latter is important in that it is desirable for resulting insulation
(in loft spaces, cavity walls, or elsewhere to be insulated) to be in a fluffed and
relatively uncompacted condition, both to achieve best insulation values and to avoid
problems that can arise, particularly for cavity walls, by reason of compaction leading
to transmission of damp through the compacted insulation.
[0003] Output is usually taken from our preferred pumping apparatus through a flexible tube
or pipe and we have found it to be advantageous for such a tube or pipe to be terminated
by a nozzle that substantially reduces in cross-section from said tube or pipe to
final exit from the nozzle. Such provision aids maintenance of an air stream with
well and evenly distributed entrained mineral fibre. However, it will be evident that
the stream must speed up through the nozzle, which leads to a tendency for unwanted
compaction of the delivered insulation material, especially when a cavity to be filled
substantially entirely nears its full state. For cavity walls, that can even lead
to localised damp transmission between its skins at least in regions adjacent to delivery
positions.
[0004] We have now found, and thus propose as an aspect of this invention, that these problems
are capable of solution by venting a delivery nozzle, preferably of the aforementioned
reducing cross-section motive, and preferably vented at a cross-section less than
its input, further preferably at its exit cross-section.
[0005] Venting from a side of the nozzle has been found to be particularly effective when
done at an acute angle of the nozzle axis and directed forwardly thereof, preferably
downwardly, and preferably at an angle substantially equal to that of a cut-off of
the end of the nozzle further preferably substantially parallel thereto. By "substantially
parallel" we intend to include both close correspondence of angles and also tolerable
variations, for example the nozzle end at about 45° and the vent angle at about 50°
for a range of about 45° to 50° for both.
[0006] It is also advantageous for the venting to be via a variable orifice, such as a suitable
valve, preferably a gate valve. Then, operators can set the vent orifice to suit particular
conditions on site and/or as desirable to suit different lengths of nozzle ends depending,
for cavity wall filling, on the thickness of the wall skin to be penetrated, usually
via a suitable sealed coupling or other sealing arrangement.
[0007] In preferred embodiments hereof, there is a cross-section reduction, preferably as
a smooth taper, of 50% or more, typically about 80%, say from nominal 50 mm diameter
to 22 mm diameter. At least then, it is ap
proproate to vent via an acutely inclined branch of equal cross-section to the nozzle
end and carrying a gate valve of the same nominal size rating. Such branch need not
exceed in length the inlet diameter or equivalent for the nozzle.
[0008] We find that, even with a forwardly directed vent, normal operation of pumping apparatus
does not cause significant loss of insulation material through the vent. Some dust
may be expelled via the vent, but significant quantities of mineral fibre appear only
when the cavity is full, thus acting as an indicator so that pumping can be stopped
before undesirable compaction can occur.
[0009] Particular preferred nozzles hereof have removable, tubular, substantially constant
section, end parts and clamping means associated with the reduced end of the remainder
of the nozzle for securement purposes and ready replacement with different length
end parts to suit particular site conditions.
[0010] In view of the above-mentioned preference for substantial parallelism of the nozzle
end and the vent, we find it advantageous to fabricate end parts complete with fixed
branches for gate valves that will also normally be attached permanently thereto.
[0011] One specific embodiment of this invention will now be described, by way of example
with reference to the accompanying diagrammatic drawing, in which:
Figure 1 is a side view of a nozzle;
Figure 2 is an end view of the same nozzle; and
Figure 3 shows a detail section at X of Figure 1.
[0012] In the drawings, a nozzle 10 comprises a main part 11 having an entry section 12
of substantially constant cross-section, actually 50 mm circular, for securement thereto
of flexible tube or pipe (not shown), say by clamp means such as Jubilee clips. Beyond
the section 12 the nozzle part 11 tapers 13 at a constant rate to a coupling 14 for
a nozzle end part 15 also of substantially constant cross-section, actually 22 mm
circular, matching the end of the tapered section 13 of the main part 11.
[0013] The coupling 14 comprises a sleeve 20 welded to the end of section 12 at its inner
end 21 which has a continuous periphery, and a split outer end 22 carrying confronting
plate-like upstands 23, 24 having registering apertures (25 shown) by which they are
interconnected via bolt-and-nut 27, 28 in order to clasp into a nozzle end part 15
that will butt neatly up to the reduced end of the section 12. Nozzle end parts 15
are, by these means, readily fitted, removed, and replaced.
[0014] The nozzle end parts 15 terminates in a sloped cut-off 30, preferably at an angle
of about 45° to 50°, actually 45° as shown.
[0015] Forwardly of its connection via the coupling 14, the nozzle end part has a vent arrangement
31 as a short branch 32 at a forward acute angle to the axis of the coupling. That
angle is also between about 45° and 50°, actually shown as 50
0, and the branch does not need to be long, in fact is shown as just less in length
than the diameter of the nozzle inlet. The angling of the vent branch 32 and the nozzle
end 30 are thus substantially parallel, i.e. within the tolerances represented by
the preferred ranges of those angles.
[0016] On the end of the branch 32 is a venting valve 40, shown diagrammatically but actually
a gate valve capable of adjustably varying the effective orifice of the vent.
1. A delivery nozzle for application to pumping apparatus for mineral fibre at least
when used as insulation comprising a body Member (10) that substantially reduces in
cross-section between an input part (12) of a first constant cross-section and an
exit part (15) of a second constant cross-section, characterised in that the exit
part (15) has vent means (31) arranged at a cross-section less than the first cross-section
of the body member.
2. A delivery nozzle as claimed in claim 1, wherein the vent means (31) is arranged
at the exit part cross-section.
3. A delivery nozzle as claimed in claim 1 or 2, wherein the vent means (31) is arranged
from a side of the nozzle at an acute angle to the nozzle axis, the vent means (31)
being directed forwardly of the nozzle.
4. A delivery nozzle as claimed in claim 3, wherein the vent means (31) is directed
downwardly, as well as forwardly, of the nozzle.
5. A delivery nozzle as claimed in any one of the preceding claims, wherein the vent
means (31) is arranged at an angle substantially equal to that of a cut-off (30) of
an end portion of the nozzle.
6. A delivery nozzle as claimed in claim 5, wherein the vent means (31) is arranged
substantially parallel to the cut-off (30).
7. A delivery nozzle as claimed in any one of the preceding claims, wherein the vent
means (31) comprises a gate valve (40) capable of adjustably varying the effective
orifice of the vent means (31), the gate valve being attached permanently to the vent
means.
8. A delivery nozzle as claimed in claim 1, wherein the cross-section reduction is
of 50% or more in a smooth taper.
9. A delivery nozzle as claimed in claim 1,7 or 8, wherein the vent means (31) further
comprises an acutely inclined branch (32) of equal cross-section to the exit part
(15), the branch having a length not exceeding the diameter of a circular section
nozzle input part.
10. A delivery nozzle as claimed in any one of the preceding claims, wherein the nozzle
comprises a removably, tubular, substantially constant cross-section, end part and
clamping means associated with the reduced end of the remainder of the nozzle for
securement purposes and ready replacement with a different length end part to suit
particular site conditions.