Apparatus and method for producing foam-containing cement slurries, and channels of such apparatus

Abstract

An apparatus (100) for producing a cement slurry containing foam comprises: a mixing chamber (101) for mixing a cementitious material and water to produce a cement slurry; and a channel (103) fluidly connected to the mixing chamber (101) at a first end (111) for receiving the cement slurry from the mixing chamber (101), the channel (103) extending from the first end (111) and terminating at a second end (112), the channel (103) comprising a mixing zone, the mixing zone having a first dimension and a second dimension, the first dimension being perpendicular to the second dimension and longer than the second dimension, the foam inlet (106) configured to introduce the foam into the channel (103). A channel (103) and a method for producing a cement slurry are also provided.

Description

[Technical Field]

[0001] The present invention relates to an apparatus for producing a cement slurry containing foam. The present invention also relates to a method for producing a cement slurry containing foam using the apparatus. [Background technology]

[0002] Gypsum occurs naturally as a raw material in the form of calcium sulfate dihydrate (CaSO₄·2(H₂O)). Gypsum-containing products, such as plasterboard, are manufactured by mixing calcined or dehydrated gypsum, i.e., calcium sulfate hemihydrate (CaSO₄·0.5(H₂O)), with water to produce a settable slurry, which is then cast into desired shapes. The calcium sulfate hemihydrate reacts with water and rehydrates to form dihydrate crystals, which are then set or dried to a solid state.

[0003] Due to their versatility, desirable mechanical properties, and the possibility of achieving a high level of finish, gypsum products are commonly found throughout buildings. Therefore, there is a desire to produce lightweight gypsum products. Reducing the amount of gypsum used would substantially reduce the resource demands of the manufacturing process and reduce material costs. Therefore, the weight of these gypsum products is very important. Summary of the Invention [Problem to be solved by the invention]

[0004] Foam is sometimes added to settable slurries to provide lightweight gypsum products. One method of combining the foam and slurry is to mix them in a mixing chamber. However, the mixing process can shear and destroy air bubbles, causing the foam to become unstable as the air bubbles disperse. Such dispersion can result in significant foam loss, creating an inefficient process and limiting the amount of density reduction that can be achieved using this method. [Means for solving the problem]

[0005] According to a first aspect of the present invention, there is provided an apparatus for producing a cement slurry including foam, comprising: a mixing chamber for mixing a cementitious material and water to produce a cement slurry; and a channel fluidly connected to the mixing chamber at a first end for receiving the cement slurry from the mixing chamber, the channel extending from the first end and terminating at a second end, the channel comprising a foam inlet for introducing foam into the channel, the channel comprising a mixing zone, the mixing zone having a first dimension and a second dimension, the first dimension being perpendicular to the second dimension and being longer than the second dimension, the foam inlet configured to introduce foam into the channel in a direction generally parallel to the second dimension.

[0006] The present invention provides an apparatus and method for efficiently and consistently combining foam with a cement slurry, such as a stucco or gypsum slurry. In the prior art, mixing means within a mixing chamber can create very high shear rates within the slurry. These high shear rates can collapse air bubbles and destabilize the foam within the mixing chamber. Therefore, introducing foam into the cement slurry within the mixing chamber can result in high levels of foam loss. The present invention addresses this issue in the prior art because the relative dimensions of the channel and foam inlet location ensure that foam is mixed uniformly throughout the cement slurry with low levels of foam loss.

[0007] More preferably, the first dimension of the mixing zone is greater than 1.1 times the second dimension of the mixing zone. Even more preferably, the first dimension of the mixing zone is greater than 1.2 times the second dimension of the mixing zone. Even more preferably, the first dimension of the mixing zone is greater than 1.4 times the second dimension of the mixing zone. Most preferably, the first dimension of the mixing zone is greater than 1.5 times the second dimension of the mixing zone.

[0008] Preferably, the first dimension of the mixing zone is at most 12 times the second dimension of the mixing zone. More preferably, the first dimension of the mixing zone is at most 10 times the second dimension of the mixing zone. Even more preferably, the first dimension of the mixing zone is at most 8 times the second dimension of the mixing zone. Most preferably, the first dimension of the mixing zone is at most 6 times the second dimension of the mixing zone.

[0009] Preferably, the channel portion between the foam inlet and the second end has a length of 400 mm to 1200 mm, more preferably, the channel portion between the foam inlet and the second end has a length of 400 mm to 600 mm.

[0010] This feature can be advantageous because the channel length between the foam inlet and the second end ensures that the foam is evenly mixed throughout the cement slurry with low levels of foam loss. Furthermore, this channel length prevents unnecessary increases in back pressure experienced by the fluid within the device, which occurs when the channel length is longer than those described herein. Furthermore, shortening the channel length facilitates easier installation of the device and provides a more compact solution.

[0011] Preferably, the foam inlet is configured to introduce foam into the mixing zone. Alternatively, the foam inlet is configured to introduce foam into a channel upstream of the mixing zone.

[0012] Preferably, the mixing zone extends over at least 50% of the distance between the foam inlet and the second end. More preferably, the mixing zone extends over at least 75% of the distance between the foam inlet and the second end. Even more preferably, the mixing zone extends over at least 90% of the distance between the foam inlet and the second end. Most preferably, the mixing zone extends between the foam inlet and said second end.

[0013] Preferably, the mixing zone extends over at least 50% of the distance between the first end and the second end. More preferably, the mixing zone extends over at least 75% of the distance between the first end and the second end. Even more preferably, the mixing zone extends over at least 90% of the distance between the first end and the second end. Most preferably, the mixing zone extends between the first end and said second end.

[0014] Preferably, the foam inlet is located closer to the first end of the channel than to the second end of the channel, and more preferably, the foam inlet is located such that the distance between the first end of the channel and the foam inlet is less than 25% of the distance between the first end of the channel and the second end of the channel.

[0015] Preferably, the mixing chamber comprises a mixing element, the mixing element being configured to rotate. Preferably, the first end of the channel is arranged such that, in use, the cement slurry exits the mixing chamber tangentially to the mixing element.

[0016] Preferably, the second end of the channel is connected to a distribution hose. Preferably, the second end of the channel is connected to a secondary chamber. Preferably, the foam inlet is positioned so that foam is injected laterally into the slurry flow in the channel. Preferably, the channel is substantially straight. Alternatively, the channel comprises a curve, a kink, or a bend.

[0017] Preferably, the cementitious material comprises at least one of calcium sulfate hemihydrate and calcium sulfate dihydrate, more preferably the cementitious material consists essentially of calcium sulfate hemihydrate.

[0018] Preferably, the foam inlet has a substantially circular cross section. Alternatively, the foam inlet has a substantially square cross section.

[0019] According to a second aspect of the present invention, there is provided a cement slurry channel configured to be in fluid connection with a cement slurry mixer, the cement slurry channel comprising a mixing zone having a first dimension and a second dimension, the first dimension being perpendicular to the second dimension and the first dimension being longer than the second dimension, and a foam inlet configured to introduce foam into the channel in a direction generally parallel to the second dimension.

[0020] In this way, a cement slurry channel is provided that provides the advantages previously described.

[0021] According to a third aspect of the present invention, there is provided a method of producing a cement slurry containing foam, the method comprising providing an apparatus as described above; introducing cementitious material and water into the mixing chamber to form a cement slurry; and introducing foam into the cement slurry via a foam inlet.

[0022] Preferably, the foam is introduced into the cement slurry at a velocity no greater than 3-5 times the velocity of the cement slurry. More preferably, the foam is introduced into the cement slurry at a velocity no greater than 3.5-4 times the velocity of the cement slurry. The velocity considered here is the average flow velocity of the foam and cement slurry through the device, not the local flow velocity.

[0023] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0024] [Figure 1] 1 shows an apparatus according to a first embodiment of the present invention; [Figure 2] FIG. 2 is a schematic diagram of a method according to a third embodiment of the present invention. [Figure 3] 1 is a graph of density deviation versus length showing the mixing uniformity of foam and cement slurry mixtures at various channel lengths. [Figure 4]1 is a graph of density deviation versus length showing the mixing uniformity of foam and cement slurry mixtures at various channel lengths. [Figure 5] 1 is a graph of pressure versus length showing back pressure within a channel. DETAILED DESCRIPTION OF THE INVENTION

[0025] 1 shows an apparatus 100 for producing a cement slurry containing foam. The apparatus 100 comprises a mixing chamber 101 and a secondary chamber 102 for mixing the cement slurry from the mixing chamber 101 with the foam. The mixing chamber 101 is connected to the secondary chamber 102 by a channel 103. The secondary chamber 102 contains a canister.

[0026] The mixing chamber 101 includes a cementitious material inlet 104 for introducing at least one cementitious material, such as calcium sulfate hemihydrate or stucco, into the mixing chamber 101, and a first water inlet 105 for introducing water into the mixing chamber 101. In this manner, the cementitious material and water can be introduced into the mixing chamber 101. The mixing chamber includes a mixing element, which includes a plurality of blades or teeth. In use, the mixing element rotates within the mixing chamber 101 to combine the water and the cementitious material to produce a cement slurry. After its production, the cement slurry can exit the mixing chamber 101 and enter the channel 103 via the mixing chamber outlet 111. The mixing chamber outlet 111 ensures that the channel 103 is in fluid communication with the mixing chamber 101 so that the cement slurry can freely pass from the mixing chamber 101 to the channel 103. The mixing chamber outlet 111 represents a first end of the channel 103.

[0027] The channel 103 comprises a foam inlet 106 for introducing foam into the channel 103. The foam inlet 106 is fluidly connected to the channel 103 to ensure that, in use, foam can freely flow into the channel 103 through the foam inlet 106. In use, foam is injected into the channel 103 via the foam inlet 106. In this way, the mixture of cement slurry and foam becomes more uniform in the channel downstream of the foam inlet 106.

[0028] In the illustrated embodiment, the foam is an aerated aqueous foam generated in a foam generator 107. The foam generator includes a second water inlet 108 for introducing water into the foam generator 107, a soap inlet 109 for introducing soap into the foam generator 107, and an air inlet 110 for introducing air into the foam generator 107. The paths of the second water inlet 108 and the soap inlet 109 meet and combine before entering the foam generator 107. Air, water, and soap are introduced into the foam generator 107 to generate foam.

[0029] The channel 103 extends from the mixing chamber outlet 111 and is substantially linear. The channel 103 terminates at a second end, which is the secondary chamber inlet 112. Thus, the cement slurry exiting the mixing chamber 101 via the mixing chamber outlet 111 and the foam entering the channel via the foam inlet 106 are combined and mixed as they flow along the channel 103. The mixed foam and cement slurry then exit the channel 103 and enter the secondary chamber 102 via the secondary chamber inlet 112. Within the secondary chamber 102, the cement slurry and the foam are further mixed. If the foam were injected directly into the mixing chamber 101, the movement of the mixing arm and the shear forces present within the mixing chamber 101 would reduce the stability of the foam. Therefore, to reduce foam damage, the foam inlet 106 is positioned in the channel 103 downstream of the mixing chamber outlet 111.

[0030] The foam inlet 106 is positioned such that the distance between the first end of the channel 103, i.e., the end located adjacent to the mixing chamber outlet 111, and the foam inlet 106 is less than 25% of the distance between the first end of the channel 103 and the second end of the channel 103, i.e., the end of the channel adjacent to the secondary chamber inlet 112.

[0031] The secondary chamber 102 is connected to a distribution hose 113. The cement slurry and foam flows exiting the channel 103 and entering the secondary chamber 102 via the secondary chamber inlet 112 are further mixed as they pass through the secondary chamber 102 before exiting the secondary chamber 102 via the distribution hose 113. Thus, there is a continuous fluid connection between the mixing chamber 101 and the distribution hose 113, which continues through the mixing chamber outlet 111, the channel 103, the secondary chamber inlet 112, and the secondary chamber 102. In this embodiment, the distribution hose 113 bifurcates at a point along its length to comprise a pair of elongated sections, each with a distribution hose outlet. While in this embodiment the distribution hose 113 is connected to the secondary chamber 102, in alternative embodiments it is contemplated that the distribution hose 113 could be connected directly to the channel 103, omitting the secondary chamber 102 from the apparatus.

[0032] The present invention further relates to a method 300 for producing a cement slurry containing foam, as shown in Figure 2. The method includes a step 301 of providing an apparatus, where the apparatus described above is provided. This is followed by a step 302 of introducing a slurry additive, where cementitious material and water are introduced into a slurry chamber through respective inlets. Next, a step 303 of introducing foam may be performed, where foam is introduced into the cement slurry in the channel through the foam inlet.

[0033] Computer modeling was performed to demonstrate the advantages of the above-described apparatus and method.

[0034] density deviation To assess the uniformity of the slurry-foam mixture, and therefore the quality of the cement slurry-foam mixture, the calculated density variation of the slurry-foam mixture at various locations within the channel is considered. In these calculations, a higher degree of density variation measured at a given point indicates a lack of uniformity in the slurry-foam mixture. Therefore, a lower degree of density variation is desirable.

[0035] To calculate the uniformity of the cement slurry and foam mixture, the flow of the cement slurry, foam, and slurry and foam mixture was modeled. Cross sections of the channel were taken and the average density and standard deviation of the density within each cross section were calculated. The average density was taken over the volume or cross section, not the average density over time. The density deviation was then calculated and was defined as:

number

[0036] If the foam is completely uniform within the slurry stream, the density deviation will be zero.

[0037] Figure 3 shows the calculated density deviation at the outlet of the distribution hose. The length of the distribution hose was modeled as 900 mm. To obtain the data in Figure 3, the foam inlet was modeled in a channel at a fixed distance of 136 mm from the mixing chamber. Furthermore, the channel was modeled as having a square cross section with dimensions of 39 mm x 39 mm.

[0038] Here, numerical modeling of the slurry and foam blend was performed using a continuous single-phase model using the ANSYS Fluent computational mechanics software package. Within the model framework, the foamed cement slurry was modeled as an effective incompressible fluid with non-Newtonian rheology depending on the local air fraction. The cement slurry was modeled as an effective fluid with 0% air fraction, while the foam was modeled as an effective fluid with 100% air fraction. In this model, Herschel-Bulkley rheology was used to describe the foam, slurry, and foamed slurry, and the coefficients used in the model were based on measurements performed with a laboratory rheometer.

[0039] As can be seen from Figure 3, when the distance between the foam inlet and the second end of the channel is short, i.e., less than 400 mm, the density deviation measured at the outlet is high. Therefore, when this distance is less than 400 mm, the slurry / foam mixture leaving the device will vary greatly, resulting in inconsistent properties of the product produced thereafter.

[0040] Figure 3 further shows that the longer the distance between the foam inlet and the second end of the channel, the less density variation is seen at the outlet. Thus, increasing the distance between the foam inlet and the second end of the channel reduces the variability in the density of the slurry and foam mixture, and concomitantly, reduces the variability in the final product produced from the slurry and foam mixture.

[0041] Figure 4 shows a model of a channel with a total length of 2000 mm, a square cross section, and dimensions of 39 mm x 39 mm. Here, a foam inlet was modeled 136 mm from the first end of the channel, introducing foam into the cement slurry. Numerical modeling of the slurry and foam blending was performed using a continuous single-phase model using the ANSYS Fluent computational mechanics software package. Within the model framework, the foamed cement slurry was modeled as an effective incompressible fluid with non-Newtonian rheology depending on the local air fraction. The cement slurry was modeled as an effective fluid with 0% air fraction, while the foam was modeled as an effective fluid with 100% air fraction. The model uses Herschel-Bulkley rheology to describe the foam, slurry, and foamed slurry, and the coefficients used in the model are based on measurements performed with a laboratory rheometer.

[0042] As can be seen in Figure 4, there is a significant increase in the calculated density deviation where the foam is introduced, after which the density deviation exhibits an exponential decrease along the length of the channel. Thus, Figure 4 confirms that increasing the length between the foam inlet and the second end of the channel reduces the observed density variation within the slurry and foam mixture.

[0043] Back pressure in the channel Back pressure is the force or resistance to flow through a system. In the present invention, both the cement slurry and the foam experience a back pressure that opposes their flow as they flow through the channel to its second end.

[0044] Therefore, the length between the foam inlet and the second end of the channel cannot be optimized solely by considering the density deviation of the slurry / foam mixture. Such optimization must also consider the back pressure on both the foam and the cement slurry as the distance between the foam inlet and the second end of the channel increases.

[0045] Figure 5 shows the change in back pressure as the length between the foam inlet and the second end of the channel increases. It can be seen that the back pressure in the channel increases as the distance between the foam inlet and the second end of the channel increases. The linear increase in back pressure with channel length on the slurry stream can be mathematically determined using the following equation, known in the literature as the Hagen-Poiseuille equation:

number

[0046] Cross-sectional profile The cross-sectional profile of the channel also affects the mixing characteristics of the slurry. To evaluate this, we numerically investigated the density deviation of several cross-sectional profiles, each with the same channel length. The cross-sectional profile variations are shown in Examples 1–4. Examples 1 and 4 have rectangular cross sections, Example 2 has a square cross section, and Example 3 has a circular cross section. Numerical modeling of the slurry and foam blending was performed using a continuous single-phase model using the ANSYS Fluent computational mechanics software package. Within the model framework, the foamed cement slurry was modeled as an effective incompressible fluid with a non-Newtonian rheology depending on the local air fraction. The cement slurry was modeled as an effective fluid with a 0% air fraction, while the foam was modeled as an effective fluid with a 100% air fraction. The model uses Herschel-Bulkley rheology to describe the foam, slurry, and foamed slurry, and the coefficients used in the model are based on measurements performed with a laboratory rheometer.

[0047] Each of Examples 1-4 has a similar cross-sectional area, and therefore the only substantial difference between each channel is the cross-sectional shape of the channel. The dimensions of each of Examples 1-4 and their cross-sectional areas are detailed in Table 1. [Table 1]

[0048] Table 2 details the height-to-width ratio and density deviation at the outlet of the distribution hose for each example. The distribution hose length was 900 mm. The channel length was 360 mm, and the foam was modeled as being injected in a direction substantially parallel to the channel width and substantially perpendicular to the channel height. [Table 2]

[0049] The model predicted similar foam penetration depths for each of Examples 1 to 4. Therefore, the ratio of foam velocity to cement slurry velocity was calculated to be similar in each case. However, differences in cross-sectional shapes for Examples 1 to 4 resulted in differences in density deviations, as shown in Table 2.

[0050] Table 2 shows that the foam is better dispersed within the slurry flow when the channel height between the foam inlet and the second end is greater than the channel width between the foam inlet and the second end, as can be seen in Example 4. Example 4 has the lowest density deviation, indicating the best uniformity of the slurry and foam mixture. Thus, this modeling indicates that the properties of the slurry and foam mixture are improved when the first dimension of the mixing zone is greater than the second dimension of the mixing zone.

[0051] The examples show that increasing the channel height relative to the channel width reduces the density deviation, but increasing the channel height beyond a certain limit can make practical integration into a plant more difficult because the channel dimensions are no longer compatible with other aspects of the equipment.

[0052] That is, the mixing chamber height determines the maximum effective height of the mixing chamber outlet, which in turn determines the maximum channel height. The foam inlet diameter in turn determines the minimum channel width. The minimum channel height is then determined to maintain the desired channel height-to-width ratio.

[0053] In the simulations described herein, the foam inlet diameter is 15 mm, and therefore, considering the maximum height of the mixing chamber, the maximum channel height is 100 mm, maintaining a height to width ratio of 6.7:1.

[0054] The advantage of limiting the minimum channel width by the foam inlet diameter is that the maximum channel height to width ratio can be calculated regardless of the line speed or size of the plant. The ratio of foam velocity introduced into the slurry to cement slurry velocity is preferably between 3 and 5. The maximum channel height to width ratio can be determined using the following calculation:

[0055] First, the velocity ratio of foam to cement slurry is

number

[0056] The velocity ratio is a function of the volumetric flow rate of the cement slurry and foam (Q), the cross-sectional area of ​​the foam inlet (A), and the cross-sectional area of ​​the channel (A). foam ), and the cross-sectional area of ​​the cement slurry (A slurry )) can be taken into consideration.

number

[0057]

number

number

[0058] The maximum channel height-to-width ratio imposed on an apparatus with a foam to cement slurry velocity ratio of 5 is 12:1. That is, a small amount of foam with a high inlet foam velocity is introduced into the cement slurry. Further calculations must be performed to ensure that the maximum channel height-to-width ratio does not exceed the channel height constraint imposed by the maximum height of the mixing chamber.

[0059] The present invention will now be described in the following terms.

[0060] Clause 1: An apparatus for producing a foam-containing cement slurry, comprising: a mixing chamber for mixing the cementitious material and water to produce a cement slurry; a channel fluidly connected at a first end to the mixing chamber for receiving the cement slurry from the mixing chamber; the channel extending from the first end and terminating at a second end, the channel including a foam inlet for introducing foam into the channel; the channel comprises a mixing zone, the mixing zone having a first dimension and a second dimension; the first dimension is perpendicular to the second dimension; the first dimension is greater than the second dimension; the foam inlet is configured to introduce foam into the channel in a direction generally parallel to the second dimension; Device.

[0061] Clause 2: The apparatus of clause 1, wherein the channel portion between the foam inlet and the mixing chamber has a length of 400 mm to 1200 mm.

[0062] Clause 3: The apparatus of clause 1 or clause 2, wherein the foam inlet is configured to introduce foam into the mixing zone.

[0063] Clause 4: The apparatus of any one of clauses 1 to 3, wherein the mixing zone extends between the foam inlet and the second end.

[0064] Clause 5: The apparatus of any one of clauses 2 to 4, wherein the mixing zone extends from the first end to the second end.

[0065] Clause 6: An apparatus according to any one of the preceding clauses, wherein the foam inlet is positioned closer to the first end of the channel than to the second end of the channel.

[0066] Clause 7: The apparatus described in Clause 6, wherein the foam inlet is positioned so that the distance between the first end of the channel and the foam inlet is less than 25% of the distance between the first end of the channel and the second end of the channel.

[0067] Clause 8: The apparatus of any one of the preceding clauses, wherein the mixing chamber comprises a mixing element, the mixing element being configured to rotate.

[0068] Clause 9: The apparatus of clause 8, wherein the first end of the channel is positioned such that, in use, the cement slurry exits the mixing chamber tangentially to the mixing element.

[0069] Clause 10: An apparatus according to any one of the preceding clauses, wherein the second end of the channel is connected to a distribution hose.

[0070] Clause 11: The device of any one of the preceding clauses, wherein the second end of the channel is connected to a secondary chamber.

[0071] Clause 12: The device of any one of the preceding clauses, wherein the channel comprises a curve, a kink, or a bend.

[0072] Clause 13: A cement slurry channel configured to be in fluid communication with a cement slurry mixer, a mixing area; the mixing zone having a first dimension and a second dimension; the first dimension is perpendicular to the second dimension; the first dimension is greater than the second dimension; the foam inlet is configured to introduce foam into the channel in a direction generally parallel to the second dimension; Cement slurry channel.

[0073] Clause 14: A method of producing a cement slurry containing foam, the method comprising providing an apparatus as claimed in any one of the preceding claims, introducing cementitious material and water into the mixing chamber to produce a cement slurry, and introducing foam into the cement slurry via the foam inlet.

[0074] Clause 15: The method of clause 14, wherein the foam is introduced into the cement slurry at a velocity that is at least three times and not more than five times the velocity of the cement slurry.

Claims

1. 1. An apparatus for producing a foam-containing cement slurry, comprising: a mixing chamber for mixing the cementitious material and water to produce a cement slurry; a channel fluidly connected at a first end to the mixing chamber for receiving the cement slurry from the mixing chamber; the channel extending from the first end and terminating at a second end, the channel including a foam inlet for introducing foam into the channel; the channel comprises a mixing zone, the mixing zone having a first dimension and a second dimension; the first dimension is perpendicular to the second dimension; the first dimension is greater than the second dimension; the foam inlet is configured to introduce foam into the channel in a direction generally parallel to the second dimension; the first dimension of the mixing zone is greater than 1.5 times the second dimension of the mixing zone; Device.

2. 2. The apparatus of claim 1, wherein the channel portion between the foam inlet and the mixing chamber has a length of between 400 mm and 1200 mm.

3. 3. The apparatus of claim 1 or claim 2, wherein the foam inlet is configured to introduce foam into the mixing zone.

4. The apparatus of any one of claims 1 to 3, wherein the mixing zone extends between the foam inlet and the second end.

5. The apparatus of any one of claims 2 to 4, wherein the mixing zone extends from the first end to the second end.

6. 10. The apparatus of claim 1, wherein the foam inlet is located closer to the first end of the channel than to the second end of the channel.

7. 7. The apparatus of claim 6, wherein the foam inlet is positioned such that the distance between the first end of the channel and the foam inlet is less than 25% of the distance between the first end of the channel and the second end of the channel.

8. 10. An apparatus according to any one of the preceding claims, wherein the mixing chamber comprises a mixing element, the mixing element being configured to rotate.

9. 9. The apparatus of claim 8, wherein the first end of the channel is positioned such that, in use, the cement slurry exits the mixing chamber tangentially to the mixing element.

10. 10. The device of claim 1, wherein the second end of the channel is connected to a distribution hose.

11. 10. The apparatus of claim 1, wherein the second end of the channel is connected to a secondary chamber.

12. 10. The device of claim 1, wherein the channel comprises a curve, a kink, or a bend.

13. a cement slurry channel configured to be in fluid communication with a cement slurry mixer, a mixing area; the mixing zone having a first dimension and a second dimension; the first dimension is perpendicular to the second dimension; the first dimension is greater than the second dimension; a foam inlet configured to introduce foam into the channel in a direction generally parallel to the second dimension; the first dimension of the mixing zone is greater than 1.5 times the second dimension of the mixing zone; Cement slurry channel.

14. 1. A method for producing a foam-containing cement slurry, comprising: Providing an apparatus according to any one of the preceding claims; introducing cementitious materials and water into the mixing chamber to form a cement slurry; introducing foam into the cement slurry via the foam inlet; A method comprising:

15. 15. The method of claim 14, wherein the foam is introduced into the cement slurry at a velocity that is at least three times and not more than five times the velocity of the cement slurry.

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