This invention relates generally to apparatus for generating and injecting a foamed polymeric resin produced with foam-producing ingredients delivered to the apparatus and relates, more particularly, to the control of the foam-producing ingredients directed through the apparatus. Foamed polymeric resins have been found to be particularly well-suited for use as a thermal and/or acoustical insulation.
The apparatus with which this invention is concerned is in the form of an elongated foam, or spray, gun having a manifold section at one end of the gun through which foam-producing ingredients are introduced to the gun and a nozzle section at the opposite end of the gun through which the generated foam is discharged from the gun. The foam-producing ingredients used to generate a foam within the gun include a liquid solution of resin, a liquid solution of foaming catalyst and a compressed gas (e.g. air), and each ingredient is introduced to the gun through the manifold section thereof and forced to mix with the other ingredients as they are forced to flow toward the opposite, nozzle, end of the gun.
An example of a foam, or spray, gun which accepts foam-producing ingredients for generating foamed polymeric resin in the manner described above is shown and described in U.S. Pat. No. 4,213,936, the disclosure of which is incorporated herein by reference.
At a jobsite (at which the generated foam is injected in place for insulative purposes), an air compressor and associated equipment for delivering the foam-producing ingredients (e.g. resin solution, foaming catalyst and compressed air) to the foam gun are commonly mounted upon a parked trailer or truck, and a foam gun, such as is described in the referenced patent, is connected to the air compressor and the associated ingredient-delivering equipment by way of flexible hoses. With the foam gun connected to the air compressor and the ingredient-delivering equipment in this manner, the foam gun can be manually transported between different locations at the jobsite where the foamed plastic resin is desired to be injected or installed.
To ensure that the quality of the foamed polymeric resin generated with the foam gun is satisfactory, it is desirable that the foam-producing ingredients are mixed together within the foam gun in predetermined ingredient-to-ingredient ratios. Otherwise, the resulting foamed resin may, for example, be too resin-rich or too resin-poor and therefore fail to provide the insulative properties desired and, in some cases, can result in foamed resin that imparts a resin-rich stain or a foaming-catalyst-rich stain to a wall structure within which the foam ingredients are injected or can result in severe foam shrinkage (as in the case of foaming catalyst-rich-material) or poor product coverage or yield (as in the case of resin-rich foamed polymeric resin).
It will therefore be understood that unless the foam ingredients are mixed or blended in a predetermined ingredient-to-ingredient ratio, undesirable consequences can result. Examples of a resin solution and a foaming agent available from the assignee of the present invention are preferably mixed together with compressed gas (e.g. air) in a one-to-one ratio to form the desired foamed resin.
A commonly-utilized method of monitoring the ratio of foam-producing ingredients being injected into place involves the monitoring of the level of ingredients remaining within the containers (e.g. tanks) from which the ingredients are being withdrawn. For example, if the desired ratio of a resin solution to foaming solution in a foamed polymeric resin is one-to-one and the rate at which such foam-producing ingredients being withdrawn from the containers is about equal, it is presumed that the ratio of such foam-producing ingredients being mixed at the foam gun is about one-to-one. However, such a method of monitoring the ratio of ingredients being mixed at the foam gun is not known to be very accurate and are time-consuming.
In particular and within conventional foam-generating and injecting systems, the sources of foam-producing ingredients (e.g. an air compressor and reservoirs containing foaming catalyst and resin solution) are commonly equipped with pressure gauges and related flow-control items (e.g. pressure regulators), but these control-related items are disposed remotely of (i.e. far upstream of) the foam gun. Consequently, to monitor or adjust the flow and ratio of the ingredients flowing to the foam gun, an operator must monitor the level of the foam-producing ingredients remaining within the containers (e.g. tanks) and make adjustments, if necessary, to the control-related items at the sources of the foam-producing ingredients—that is to say, remotely of (i.e. far upstream of) the foam gun. Because of the remote disposition of the foam gun to the control-related items, the accuracy of an adjustment in the flow of foam-producing ingredients through the foam gun in response to an adjustment at the sources of the foam-producing ingredients is necessarily delayed until sufficient amounts of ingredients are removed from the containers (e.g. tanks) so that the operator can make a subsequent determination of the ratio of foam-producing ingredients being mixed at the foam gun.
Furthermore, if the operator who must monitor and make appropriate adjustments to the flow control items at a parked truck is also the individual who must operate the foam gun (which is typically the case), then the foam gun operator will necessarily have to travel from a location at which the foamed resin is desired to be injected each time that the reservoir levels and/or flow control items must be checked or adjustments to the flow of ingredients to the foam gun must be made. This method of monitoring the flow of the foam-producing ingredients can be both burdensome and time-consuming.
Furthermore, the portion of the flexible hoses extending between the flow control valves and the foam gun in conventional systems are typically large in capacity. Both the time delay involved between an adjustment in the flow rate of a foam-producing ingredient and a corresponding drop in the reservoir level of the ingredient at the foam truck, along with the relative difficulty in accruately measureing the reservoir levels to determine the precise consumption of each foam-producing ingredient present difficulties in accurately controlling the flow of the various foam-producing ingredients through the foam gun and also allow a portion of the building structure to be insulated with foam of undetermined quality since the ratio of foam ingredients cannot quickly be determined.
Accordingly, it is an object of the present invention to provide a new and improved apparatus of the aforedescribed class which obviates the need for an operator to monitor or make adjustments to the reservoir levels of foam-producing ingredients remote of (i.e. far upstream of) the apparatus.
Another object of the present invention is to provide such an apparatus for accurately monitoring and controlling the flow of foam-producing ingredients through the apparatus.
Still another object of the present invention is to provide such an apparatus which circumvents burdensome and time-consuming difficulties associated with the control of foam-producing ingredients in conventional systems for generating and injecting foamed resin.
Yet another object of the present invention is to provide such a foam gun which is uncomplicated in structure, yet effective in operation.
A further object of the present invention is to provide an improved method of regulating flow of various ones of the foam-producing ingredients.
A still further object of the present invention is to provide such an apparatus including means for monitoring the material flow with a much higher accuracy than can be achieved through the current techniques of visually inspecting tank levels of foam-producing ingredients during a foam-generating process.
This invention resides in an improvement in an apparatus for generating and injecting a foamed polymeric resin formed by the mixture of a plurality of foam-producing ingredients delivered to the apparatus from sources of foam-producing ingredients wherein the foam-producing ingredients include liquid ingredients and wherein the apparatus includes a manifold section into which the foam-producing ingredients are introduced to the apparatus.
The improvement includes means for monitoring the flow of at least one liquid foam-producing ingredient introduced to the manifold section of the apparatus and adjustable valving means for controllably regulating the flow of the at least one liquid foam-producing ingredient into the manifold section between two preselected flow rates. Each of the monitoring means and the adjustable valving means are associated with the manifold section of the apparatus so that the flow of the at least one liquid foam-producing ingredient introduced to the manifold section can be monitored and controlled at the apparatus.
Turning now to the drawings in greater detail and considering first
With reference still to
One passageway, indicated 34 in
The other two passageways 32 and 36 provide conduits in the head 30 which are adapted to accept the other two foam-producing ingredients (i.e. compressed gas and foaming catalyst) delivered, respectively, to the foam gun 20 from a compressed gas source 52 (e.g. an air compressor) and a source 54 of liquid foaming catalyst. The gun 20 further includes a cylindrical tube 46 which is threadably joined to the head 30 so that the interior of the tube 46 is in communication with the hollow interior 38 of the head 30. Consequently, the compressed gas and foaming catalyst which are delivered to the gun 20 by way of the passageways 32 and 36 are forced to flow through the tube 46 toward the nozzle section 28. As the foaming catalyst and gas are directed through the tube 46, the foaming catalyst and gas mix with one another to form a foamy substance comprised of spherical bubbles of gas surrounded by a film layer of liquid foaming catalyst. The foamy substance generated with the mixture of foaming catalyst and gas is eventually forced into the nozzle section 28 where it is mixed with the resin solution exiting the conduit 44 to thereby form the desired foamed polymeric resin. It follows that the space provided between the inside wall of the cylindrical tube 46 and the outer wall of the central conduit 44 provide a foaming chamber, indicated 50, for the foam gun 20, and it is within this space, or foaming chamber 50, that a filler material (e.g. glass beads or metal wool) can be positioned for enhancing the blend of the foaming catalyst and the gas flowing through the foaming chamber 50.
With reference still to
Mounted at opposite ends of the central conduit 44 are perforated screens 61, 62 (
The discharge end of the conduit 44 terminates at a spray tip 70 through which the resin solution is discharged in a spray pattern within the nozzle section head 56 for mixing of the resin solution with the foamy substance generated with the foaming catalyst and gas. Although a detailed description of the spray tip 70 and its componentry is not believed to be necessary, suffice it to say that the spray tip 70 includes a metering orifice of a size and shape to provide a hollow cone spray of resin within the mixing chamber for mixing with the foamy mixture of foaming catalyst and gas flowing through the head 56 of the nozzle section 28 so that the desired foamed polymeric resin is discharged through the discharge portion 68 of the nozzle section head 56. For a more complete description of a spray tip suitable for use in the foam gun 20, reference can be had to U.S. Pat. No. 4,213,936, the disclosure of which is incorporated herein by reference.
It is a feature of the foam gun 20 that its monitoring means 23 and its adjustable valving means 25 are associated with the manifold section 26 for enabling an operator to monitor the flow rate of each liquid foam-producing ingredient delivered to the foam gun 20 at the foam gun 20 and for enabling the operator to make adjustments, as needed, to the flow rate of each foam-producing ingredient delivered to the foam gun 20 at the gun 20. To this end, the monitoring means 23 includes two flow meters 82 and 84 which are each connected in flow communication with a corresponding one of the passageways 34 and 36 so that the flow rate of the liquid ingredients (i.e. the foaming catalyst and resin solution) entering the corresponding passageway 34 or 36 can be continually monitored. Each flow meter 82 or 84 has a display 86 which is adapted to provide the operator with a continuous readout of the flow rate of the liquid foam-producing ingredient entering the corresponding passageway 34 or 36 and, as is the case with the depicted foam gun 20, is preferably a digital flow meter whose display 86 is a digital display comprised of multiple groups of LEDs or LCDs. Such multiple groups of LEDs or LCDs of one flow meter 84 is indicated 90a-90c in
As far as the control of the air flow rate to the foam gun 20 is concerned, there is provided a needle valve 158 (
With reference still to
Unlike a shut-off valve which can only be used to alter the flow rate of a fluid flowing therethrough between a fully open and a fully closed condition, each valve 96 or 98 enables an operator to adjust the flow rate of fluid (i.e. a foam-producing ingredient) therethrough between a number of possible flow rates. In other words, by rotating a knob 102 of any of the valves 96 and 98 relative to its corresponding valve body in one rotational direction or the opposite rotational direction by an incremental amount, the flow rate of liquid permitted to flow through the valve 96 or 98 is adjusted by a corresponding, or incremental, amount. It follows that each valve 96 or 98 provides means by which the flow of each liquid foam-producing ingredient introduced to the foam gun 20 by way of the manifold section 24 can be controllably regulated between two rates for accurately controlling the foam-producing ingredients to the foam gun 20.
As best shown in
Because the flow monitoring means 23 and the flow adjustable valving means 25 are incorporated within the foam gun 20, an operator who operates the foam gun 20 need not return to the sources of the resin solution or foaming catalyst in order to check or make necessary adjustments to the flow rates of the liquid ingredients flowing to the foam gun 20. Such an advantage can be readily appreciated when compared to the conventional foam-generating and injecting systems in which the sources of foam-producing ingredients (i.e. resin solution, foaming catylst and compressed gas) are commonly stationed at a stationary location, indicated 120 in
Further still and because the adjustable valving means 25 are connected in relatively close flow proximity to the hollow interior 38 of the head 30 of the manifold section 26, any adjustment of the valves 96 and 98 of the adjustable valving means 25 results in a prompt adjustment of the flow rate of the liquid foam-producing ingredients entering the head 30. This is in sharp contrast to making an adjustment in the flow rate of a flow-producing ingredient with a flow control-related device disposed remotely of (flow-wise) the foam gun (such as at a parked truck) which necessarily results in a delayed response in the ingredient flow rate at the foam gun.
Furthermore, because the adjustable valving means 25 of the foam gun 20 enables the flow rate of each liquid foam-producing ingredient to the manifold section head 30 to be adjusted in small increments, the flow of the various foam-producing ingredients can be selected with a high degree of accuracy, and the foam gun 20 is further advantageous in this respect. One more advantage provided by the present invention relates to the size of the flexible hoses used to conduct each foam-producing ingredient to the foam gun 20 in relation to the volumetric flow rates of the ingredients involved. More specifically, the internal volume of the flexible hoses joining each source of foam-producing ingredient is relatively large in relation to the volumetric flow rates of the ingredient flowing into the foam gun 20, so that as long as adjustments are made to the volumetric flow rates of the various foam-producing ingredients remote of the foam gun, the flexible hoses provide, in effect, a reservoir which could permit seepage of the foam-producing ingredients to flow into the foam gun unchecked. Because the flow control valves 96, 98 of the depicted foam gun 20 are situated in relatively close proximity to the hollow interior 38 of the manifold section 26, there is no unwanted seepage of liquid foam-producing ingredients into the hollow interior 38 of the manifold section 26 upon adjustment of the flow or shut-off of the flow of foam-producing ingredients into the foam gun 20 by way of the valves 96 and 98.
It will be understood that numerous modifications and substitutions can be had to the aforedescribed embodiment without departing from the spirit of the invention. For example, although the aforedescribed apparatus 20 has been shown and described as including a manifold section 26 to which flow meters 82 and 84 and manually-operable valves 96 and 98 are directly connected, an apparatus in accordance with the principles of the present invention can include a manifold section within which flow meters and flow control valves are integrally mounted. For example, there is illustrated in
Accordingly, the aforedescribed embodiment 20 is intended for the purpose of illustration and not as limitation.