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(11) | EP 1 688 186 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Dispenser voor schuimende kunststoffen |
| (57) Dispenser for foaming plastics, such as polyurethane foam, with a foam channel (1)
that is provided at one end with an adapter (2) for connecting a pressurised container
(3) containing the foaming plastic and has an outlet opening (4) at the other end,
as well as a metering mechanism (5) for regulating the quantity of foam that passes
through the channel, wherein the foam channel (1) extending from the adapter (2) to
the outlet opening (4) is made straight and wherein the metering mechanism (5) has
a valve, especially a ball valve, in the straight foam channel (1), which valve can
move between a first fully closed position and a second fully open position.
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[0001] The invention relates to a dispenser for foaming plastics, such as polyurethane foam, with a foam channel that is provided at one end with an adapter for connecting a pressurised container containing the foaming plastic and has an outlet opening at the other end, as well as a metering mechanism for regulating the quantity of foam that passes through the channel.
[0002] Such a dispenser is disclosed, for example, in EP 0 255 060 in which a spray gun is described with a channel that is provided at one end with a connection for a pressurised container and has an outlet opening at the other end, as well as a control valve operated by means of a handle and a ball valve fitted in the channel close to said connection. This ball valve is used to replace the non-return valve known in the state of the art and has the advantage of providing an improved sealing effect, as a result of which hardening of the foam located in the channel between the control valve and this ball valve is prevented. A further advantage claimed is that the pressurised container can now be emptied to normal ambient pressure because the pressure from the pressurised container does not have to counteract the spring force of a non-return valve.
[0003] One disadvantage of said known dispenser is that it is relatively expensive because two valves are used, i.e. the control valve for metering and the ball valve for sealing the channel on the container side; in addition, the various components must be assembled with a housing. A further disadvantage of the embodiment shown is that this has a channel with a V-shaped bend, which makes it harder to clean hardened foam out of this channel.
[0004] The aim of the present invention to provide a dispenser for foaming plastics which is easy to clean, is reliable in operation and is, moreover, relatively economical to manufacture.
[0005] This aim is achieved in that the foam channel extending from the adapter to the outlet opening is made straight and in that the metering mechanism has a valve, especially a ball valve, in the straight foam channel, which valve can move between a first fully closed position and a second fully open position.
[0006] The term "ball valve" must be understood in a wide sense in this context, covering valves with a rotating body provided with a bore, whereby the valve is closed when the bore is oriented transversely relative to the channel and open when the bore connects sections of the channel located at each end of the bore. The rotating body can therefore just as easily be a cylindrical body as a spherical body.
[0007] The advantage of such an embodiment is that the ball valve has practically no influence on the foam channel passage in the fully open position which, in combination with the foam channel extending in a straight line from the adapter to the outlet opening, results in a dispenser which is very easy to clean. If foam has hardened in the channel, this can easily be removed by clearing the channel with a stick or rod. Such a stick or rod is preferably made of a material that will not damage the dispenser, such as a plastic.
[0008] In addition, a ball valve provides a very reliable seal and it can also be operated in the event that foam has hardened in the ball valve, because no material is displaced when the valve is operated.
[0009] Furthermore, it is very easy to construct the dispenser in that only one valve has to be provided and, because no separate housing with a handle has to be provided, the pressurised container can be held in the hand and manipulated together with the dispenser mounted on it.
[0010] A different type of valve other than a ball valve, for example a sliding valve, is also conceivable.
[0011] The metering mechanism preferably additionally has an operating handle for moving the ball valve between a fully closed position for halting the material flow and an at least partially open position for delivering foam.
[0012] The operating handle is preferably fixed to the ball of the ball valve and the dispenser is designed such that the operating handle can be pivoted between a first position corresponding to the closed position of the ball valve for halting the material flow and a second position corresponding to the fully open position of the ball valve to enable the foam channel to be cleaned.
[0013] Furthermore, the operating handle is preferably designed such that, with the dispenser mounted on the pressurised container, said handle can be pivoted from the first position to an intermediate position between the first position and the second position, which intermediate position is defined by the operating handle coming to a stop against the pressurised container, and that, with the dispenser detached from the pressurised container, said handle can be pivoted from the first position to the second position. It is possible in this way to prevent the ball valve from being accidentally fully opened with the dispenser mounted on the pressurised container, as this would result in excessively fast dispensing of foam, while the ball valve can still be fully opened for cleaning the foam channel with the dispenser detached from the pressurised container.
[0014] Furthermore, a spring element is preferably provided for pretensioning the metering mechanism in the state where the ball valve is in the closed position, so that a force must be exerted against this pretension to operate the metering mechanism for dispensing foam and that, in the absence of this operating force, the metering mechanism automatically returns to the state where the ball valve is in the closed position.
[0015] Furthermore, a releasable locking element is preferably provided for locking the metering mechanism in the state where the ball valve is in the closed position, so that it is possible to prevent accidental operation of the metering mechanism.
[0016] Furthermore, the outlet opening is preferably provided with connecting means for a hose, for example flexible or rigid, such as a disposable plastic tube, for directing the foam to the desired location. Such a plastic tube can, for example, be provided with a bend and can be of any desired length, so that even locations which are difficult to access can be reached.
[0017] Preferably, the section of the foam channel located between the adapter and the ball valve is made as short as possible to minimise the amount of foam exposed to the atmosphere when the adapter is detached from an empty pressurised container.
[0018] The invention will now be explained in more detail on the basis of an embodiment, with reference to the drawings, in which:
Figure 1 is a front view in section of a dispenser according to the invention, and
Figure 2 is a side view of the dispenser according to the invention, in which three positions of an operating handle are shown.
[0019] Figure 1 shows a section through the dispenser according to the invention. This comprises a foam channel 1 that is provided at one end with an adapter 2 for connecting a pressurised container 3 containing the foaming plastic and has an outlet opening 4 at the other end, as well as a metering mechanism 5 for regulating the quantity of foam that passes through the channel. The foam channel 1 extends from the adapter 2 to the outlet opening 4 and is made straight. A ball valve 6 which can move between a first fully closed position and a second fully open position is provided in the foam channel 1.
[0020] The metering mechanism has an operating handle 7 which is fixed to the ball 8 of the ball valve 6 and the dispenser is designed such that the handle can be pivoted between a first position p1 corresponding to the closed position of the ball valve and a second position p2 corresponding to the fully open position of the ball valve, see Figure 2. When the ball valve is in the fully open position, it is possible to clear the foam channel with a stick or rod or the like, so that contamination such as hardened foam can be removed mechanically. To this end, the handle has a widened section 9, so that, when the dispenser has been detached from the pressurised container, it can pass by the adapter 2 and can be moved into the second position p2. When the handle is in the second position p2, it is possible to connect a pressurised container or reservoir to the adapter, for example a container with a cleaning fluid such as acetone, to clean the foam channel.
[0021] In addition, the operating handle is designed such that, with the dispenser mounted on the pressurised container, said handle can be pivoted from the first position p 1 to an intermediate position p3 between the first position p1 and the second position p2, which intermediate position p3 is defined by the operating handle 7 coming to a stop against the pressurised container 3.
[0022] An extension spring 10 acts on the operating handle 7 and pretensions it in the position where the ball valve is closed, the spring 10 tensioning the operating handle 7 against stop 11.
[0023] A safety catch 12 is attached to the operating handle 7 such that it can hinge and can be moved between a folded position whereby the movement of the operating handle is not impeded and an extended position whereby the safety catch 12 is braced against a pressurised container 3 mounted on the adapter 2, thereby barring movement of the operating handle and locking the metering mechanism in the position in which the ball valve is closed.
[0024] The outlet opening 4 of the foam channel is provided with connecting means for a hose 13 in the form of a hose post 14 which is screwed into the ball valve housing. The hose post 14 is provided with corrugations for gripping a hose 13 slid over the hose post. The hose 13 shown is somewhat rigid and is provided with a bend, which enhances the usefulness of the dispenser for dispensing foam in locations with difficult access. If the hose becomes blocked with, for example, hardened foam, it can be thrown away.
1. Dispenser (16) for foaming plastics, such as polyurethane foam, with a foam channel
(1) that is provided at one end with an adapter (2) for connecting a pressurised container
(3) containing the foaming plastic and has an outlet opening (4) at the other end,
as well as a metering mechanism (5) for regulating the quantity of foam that passes
through the channel, characterised in that the foam channel (1) extending from the adapter (2) to the outlet opening (4) is
made straight and in that the metering mechanism (5) has a valve (6), especially a ball valve, in the straight
foam channel (1), which valve can move between a first fully closed position and a
second fully open position.
2. Dispenser according to Claim 1, wherein the metering mechanism (5) additionally has
an operating handle (7) for moving the ball valve (6) between a fully closed position
and an at least partially open position.
3. Dispenser according to Claim 2, wherein the operating handle (7) is fixed to the ball
(8) of the ball valve (6) and the dispenser (16) is designed such that the operating
handle can be pivoted between a first position corresponding to the closed position
of the ball valve and a second position corresponding to the fully open position of
the ball valve.
4. Dispenser according to Claim 3, wherein the operating handle (7) is designed such
that:
• with the dispenser (16) mounted on the pressurised container (3), said handle can be pivoted from the first position to an intermediate position between the first position and the second position, which intermediate position is defined by the operating handle (7) coming to a stop against the pressurised container (3), and
• with the dispenser (16) detached from the pressurised container (3), said handle can be pivoted from the first position to the second position.
5. Dispenser according to one of the preceding claims, wherein a spring element is provided
for pretensioning the metering mechanism in the state where the ball valve (6) is
in the closed position.
6. Dispenser according to Claim 5, wherein a spring (10) acts on the operating handle
(7) for pretensioning it in the position where the ball valve (6) is in the closed
position.
7. Dispenser according to one of the preceding claims, wherein a releasable locking element
is provided for locking the metering mechanism in the state where the ball valve (6)
is in the closed position.
8. Dispenser according to Claim 7, wherein a locking element (12) acts on the operating
handle (7) for locking it in the position where the ball valve (6) is closed.
9. Dispenser according to one of the preceding claims, wherein the outlet opening (4)
is provided with connecting means (14) for a hose (13).
10. Dispenser according to one of the preceding claims, wherein the section of the foam
channel located between the adapter (2) and the ball valve (6) is made as short as
possible.