RU2825299C1 - Hose - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to a hose for use in making a construction article from gypsum mortar. Method of making a gypsum article comprises steps of kneading gypsum mortar in a mixer, removing said gypsum mortar from said mixer through a hose onto a moulding table and curing said gypsum mortar. Hose comprises a first section, a second section and a third section located between said first section and said second section. First section has cross-section area A₁. Second section has cross-section area A₂. A₁ is at least twice more than A₂. Said first section is hydraulically connected to said second section, and when used, said first section is located upstream of said second section. Third section has cross-section area A₃. Said first section is connected to said third section by means of an elbow, At that, said first section features maximum dimension d₁ in plane perpendicular to its lengthwise axis. At that, said elbow has outer radius of curvature equal to at least half of d₁. Longitudinal axis of said first section lies perpendicular to longitudinal axis of said third section and longitudinal axis of said second section, and longitudinal axis of said second section lies parallel to longitudinal axis of said third section.

EFFECT: increased uniformity of distribution of gypsum solution on moulding table, increased homogeneity of solution flow.

9 cl, 6 dwg

Description

Field of technology to which the invention relates

The present invention relates to a hose, and more particularly to a hose for use in the production of a gypsum mortar building product.

State of the art

The production of building products such as gypsum plasterboard involves mixing gypsum mortar in a mixer. Various types of mixers are well known in the art, with the most common types being tangential outlet mixers and bottom outlet mixers. In cases where a bottom outlet mixer is used, a hose is connected to the bottom of the mixer to direct the gypsum mortar from the mixer to the molding table. Alternatively, a tangential outlet mixer may be used. The gypsum mortar exits the side of the tangential outlet mixer before being discharged into the hose through a container.

Disclosure of the essence of the invention

The applicant found that when using a mixer with a bottom outlet, the rotational motion of the gypsum slurry in the mixer is transmitted through the hose, resulting in a significant rotational component in the flow of gypsum slurry within the hose.

The applicant also found that a rotational component occurs within a hose connected to a mixer with a tangential outlet. In this case, the container introduces a rotational component into the flow of gypsum slurry. Thus, regardless of whether a mixer with a bottom outlet or a tangential outlet is used, the gypsum slurry entering the hose has a rotational component in its flow.

The rotational component associated with the flow of gypsum can create problems in the production of building products. In cases where the gypsum slurry exits the hose onto the molding table through a single outlet, the rotational component of the fluid flow can cause uneven distribution of the gypsum slurry across the molding table. In cases where the gypsum slurry exits the hose onto the molding table through multiple outlets, the rotational component present in the flow of gypsum slurry can cause even more problems. In this case, different volumes of gypsum slurry can exit each individual outlet, creating difficulties when uniform distribution of gypsum slurry across the molding table is required.

In view of the above, it is advisable to reduce the rotational component in the flow of gypsum mortar inside the hose. The applicant has come to the understanding that reducing the rotational component of the gypsum mortar inside the hose can lead to a more uniform distribution of the gypsum mortar on the molding table. The present invention is aimed at solving at least this problem.

According to a first aspect of the present invention, a hose is provided for use in the production of a building product from gypsum mortar, wherein the hose comprises a first section having a cross-sectional area A ₁ and a second section having a cross-sectional area A ₂ , wherein the first section is hydraulically connected to the second section, wherein in use the first section is located upstream of the second section, wherein A ₁ is at least twice as large as A ₂ , wherein the hose comprises a third section having a cross-sectional area A ₃ , located between the first section and the second section, wherein the first section is connected to the third section by means of an elbow, wherein the first section has a largest dimension d ₁ in a plane perpendicular to its longitudinal axis, and wherein the elbow has an outer radius of curvature equal to at least half of d ₁ .

Thus, a hose is proposed that increases the homogeneity with which a fluid, most often a gypsum solution, is distributed over a surface. The applicant has conducted numerical simulations and physical experiments that show that providing a hose with the above features improves the flow characteristics. The applicant believes that these improved flow characteristics are due to a number of phenomena in the claimed hose, the most significant of these features being the creation of a recirculation zone within the hose body that acts to break up the rotational component of the fluid flow as it enters the hose. Typically, in the production of a gypsum mortar building product, this rotational component is introduced into the gypsum flow through a bottom-outlet mixer or a tangential-outlet mixer container.

Preferably, A ₁ is the maximum cross-sectional area of the first section. Preferably, A ₂ is the minimum cross-sectional area of the second section.

A ₁ is at least twice as large as A ₂ . More preferably, A ₁ is at least three times as large as A ₂ . When the hose is sized to these extremes, the recirculation zone within the hose becomes larger and more significant, providing for more efficient destruction of the rotational component of the gypsum flow, increasing the uniformity of any flow leaving the hose.

Preferably, A ₁ is no more than 4 times A ₂ . While the applicant's modeling work shows that the beneficial effect of increasing the ratio of A ₁ to A ₂ continues above this value, this upper limit is often preferred because it allows the hose to be installed into existing gypsum board manufacturing systems without adding unnecessary bulk.

The hose comprises a third section having a cross-sectional area A ₃ located between the first section and the second section. Preferably, A ₁ has the same size or is larger than A ₃ . Preferably, A ₁ is no more than 4 times larger than A ₃ . In the case where A ₃ ≤ _{A 1} ≤ 4 A ₃ , the fluid flow in the hose causes vortex flows when it encounters the restriction of the third section. These vortex flows effectively counteract the rotational component of the fluid when it enters the restriction, which results in a balanced flow leaving the hose. Preferably, A ₃ is the minimum cross-sectional area of the third section.

Preferably, the longitudinal axis of the first section lies generally perpendicular to the longitudinal axis of the third section. Preferably, the longitudinal axis of the first section lies generally perpendicular to the longitudinal axis of the second section. Preferably, the longitudinal axis of the second section lies generally parallel to the longitudinal axis of the third section.

The first section is connected to the third section by means of a knee. The first section has the largest dimension d ₁ in a plane perpendicular to its longitudinal axis. More preferably, d ₁ is the largest dimension of the first section in a plane perpendicular to its longitudinal axis, wherein said plane is the plane of the first section closest to the knee. The knee has an external radius of curvature equal to at least half of d ₁ . Preferably, the external radius of curvature of the knee is no more than twice as large as d ₁ . Advantageously, the radius of curvature within this range increases the size of the recirculation zone inside the hose.

Preferably, the elbow has a constant outer radius of curvature. Alternatively, the elbow has a variable outer radius of curvature.

Preferably, the knee has an inner radius of curvature, wherein the inner radius of curvature is equal to the outer radius of curvature minus d ₁ . When the outer radius of curvature is less than or equal to d ₁ , the inner radius of curvature is zero. Preferably, the inner radius of curvature is in the range 0≤R _In ≤d ₁ . More preferably, the inner radius of curvature is zero.

Preferably, the second section comprises at least two subsections, wherein the total cross-sectional area of the subsections is equal to A ₂ . If the second section comprises a plurality of subsections, A ₂ is taken as the combined total cross-sectional area of all subsections. If the second section comprises a plurality of subsections, then the non-uniform distribution of the fluid exiting the hose can often be visualized as different volumes of fluid exiting each individual outlet. If the second section comprises a single outlet with no subsections, then the non-uniform distribution of the fluid exiting the second section can often be observed by a preferential distribution of the fluid over a mold table or the like.

Preferably, the subsections diverge as they move away from the first section. Preferably, the cross-sectional area of each subsection in the plurality of subsections is substantially the same.

Preferably, the first section has a substantially circular cross-section. Preferably, the second section has a substantially circular cross-section. Preferably, the third section has a substantially circular cross-section. Preferably, the subsections in the plurality of subsections have a substantially circular cross-section. Any combination of the disclosed cross-sections is envisaged.

Preferably, the first section has substantially the same cross-sectional area along most of its length. More preferably, the first section has substantially the same cross-sectional area along at least 75% of its length. Even more preferably, the first section has substantially the same cross-sectional area along at least 90% of its length. Most preferably, the first section has substantially the same cross-sectional area along its entire length.

Preferably, the second section has substantially the same cross-sectional area along most of its length. More preferably, the second section has substantially the same cross-sectional area along at least 75% of its length. Even more preferably, the second section has substantially the same cross-sectional area along at least 90% of its length. Most preferably, the second section has substantially the same cross-sectional area along its entire length.

Preferably, if the second section comprises a plurality of subsections, each subsection has substantially the same cross-sectional area along most of its length. More preferably, each subsection has substantially the same cross-sectional area along at least 75% of its length. Even more preferably, each subsection has substantially the same cross-sectional area along at least 90% of its length. Most preferably, each subsection has substantially the same cross-sectional area along its entire length.

Preferably, the third section has substantially the same cross-sectional area along most of its length. More preferably, the third section has substantially the same cross-sectional area along at least 75% of its length. Even more preferably, the third section has substantially the same cross-sectional area along at least 90% of its length. Most preferably, the third section has substantially the same cross-sectional area along its entire length.

Preferably, the second section extends below a plane that contains the longitudinal axis of the third section. Preferably, the second section is longer than the first section. Preferably, the hose comprises plastic. More preferably, the hose essentially consists of plastic.

Preferably, the hose has a plane of mirror symmetry. More preferably, the longitudinal axis of the first section, the second section or the third section lies in the plane of mirror symmetry.

A second aspect of the present invention is the use of a hose as previously disclosed in the manufacture of a building product.

According to a third aspect of the invention, a method for dispensing a gypsum solution is proposed, including providing a hose with a plurality of distribution sections, wherein the hose comprises at least two sections with corresponding cross-sectional areas A ₁ and A ₂ , wherein the ratio of A ₁ to A ₂ is such that the flow asymmetry in said distribution sections is below 1%.

Preferably, the method is a method for dispensing a gypsum solution for producing a gypsum-based product.

Preferably, the method further includes providing a mixer, providing a molding table, and dispensing gypsum mortar from the mixer through a hose onto the molding table.

Preferably, the hose is a previously opened hose.

According to a fourth aspect of the present invention, a method for producing a gypsum article is provided, comprising the steps of mixing a gypsum solution in a mixer, discharging the gypsum solution from the mixer through a hose, as previously disclosed, onto a molding table, and curing the gypsum solution.

Preferably, the step of curing the gypsum mortar includes heating the mortar.

Preferably, the step of mixing the solution comprises mixing the solution in a mixer with a tangential outlet or in a mixer with a bottom outlet.

Preferably, the gypsum solution contains a foaming agent. More preferably, the method includes adding the foaming agent to the gypsum solution in a container of a mixer with a tangential outlet. The foaming agent is used to reduce the density of gypsum products. Lightweight gypsum products are made by adding an increased amount of foaming agent.

Brief description of the drawings

Embodiments of the present invention will be disclosed by way of example only and with reference to the accompanying drawings, in which:

Fig. 1 shows an image of a prior art hose used in the production of a construction product;

Fig. 2 shows an illustration of a hose according to the present invention used in the production of a building product;

Fig. 3 shows a graph illustrating the heterogeneity of the right/left flows of numerically simulated hose systems;

Fig. 4 shows a graph illustrating the effect of changing the ratio of A ₁ to A ₂ on the simulated flow rate deviation;

Fig. 5 shows a graph illustrating the effect of changing the ratio of A ₁ to A ₃ on the simulated flow rate deviation; and

Fig. 6 shows a graph illustrating the effect of changing the outer radius of curvature of the elbow section on the simulated flow rate deviation.

Implementation of the invention

Fig. 1 shows a sleeve or hose 100, as known in the art. As can be seen from the inset in Fig. 1, the hose comprises a first section 110 and a second section 120 comprising two subsections 121. The first section 110 and the second section 120 are hydraulically connected, wherein the first section 110 is connected to a container (not shown) of a mixer with a tangential outlet (not shown).

As can be seen from Fig. 1, the hose 100 is used to dispense gypsum mortar 160 onto the molding table 170 as part of the process of producing a building product. In this case, the building product being formed is a lightweight gypsum board.

Fig. 1 further illustrates the uneven nature of the delivery of gypsum solution 160 by the prior art hose 100 onto the mold table 170. The flow of gypsum solution 160 from the right subsection 121 of the second section 120 is much greater than the flow of gypsum solution 160 exiting the left subsection 121 of the second section 120, as can be seen from the distance that the gypsum solution 160 from each subsection 121 travels along the length of the mold table 170. The distance between the ends of the gypsum solutions exiting each subsection is designated as X ₁ in Fig. 1.

Fig. 2 shows a hose 200 according to the present invention. As can be seen from the inset in Fig. 2, the hose comprises a first section 210, a second section 220 comprising two subsections 221 and a third subsection 230 located between the first section 210 and the second section 220. The first section 210, the second section 220 and the third section 230 are hydraulically connected to each other, wherein the first section 210 is connected to a container (not shown) of a mixer with a tangential outlet (not shown). The hose further comprises an elbow that connects the first section 210 to the third section 230.

As can be seen from Fig. 2, the sleeve or hose 200 is used to dispense gypsum mortar 260 onto the molding table 270 as part of the process of manufacturing a building product. In this case, the building product being formed is, similar to the above, a lightweight gypsum board with the same composition that was used in the manufacturing example shown in Fig. 1.

In contrast to Fig. 1, Fig. 2 illustrates a hose 200 that delivers gypsum slurry 260 much more uniformly across the mold table than the hose 100 of the prior art shown in Fig. 1. While the flow of gypsum slurry 260 from the right subsection 221 of the second section 220 is still greater than the flow of gypsum slurry 260 exiting the left subsection 221 of the second section 220, the difference between the two subsections 221 is significantly reduced. The length X ₂ is much shorter than the length X ₁ , indicating that the hose 200 significantly increases the uniformity of the flow through the two subsections 221.

While the hose 200 has a clear advantage over the prior art hose 100, the two hoses differ from each other in a number of design features. Therefore, in order to identify design features that contribute to improving the flow characteristics of the hose 200, numerical simulations were performed.

Numerical modeling

Basic model

In order to provide reliable data, as a first step, numerical models were developed to reproduce the physical results observed in Figs. 1 and 2. For this purpose, numerical simulations were performed using a continuous single-phase model using the ANSYS Fluent computational dynamics software package. Within the framework of the model, the foamed gypsum mortar used in the tests shown in Figs. 1 and 2 was modeled as an effective incompressible fluid with non-Newtonian rheological properties. In addition, the Herschel-Bulkley rheological law was used in the model, with the coefficients used in the model being based on experimental measurements made using a laboratory rheometer.

In addition, to reproduce the test conditions used to obtain the images in Fig. 1 and Fig. 2, the numerical model is based on a system using a tangential outlet mixer and a container. In such a system, the rotational component of the flow is introduced into the gypsum slurry by the container. In alternative systems using a bottom outlet mixer, the mixer itself is responsible for the rotational component of the flow in the gypsum slurry as it enters the hose. Thus, while the numerical models considered in the present application are based on the use of a tangential outlet mixer, the results are also valid for bottom outlet mixers, since both mixer options introduce equivalent rotational components into the flow of gypsum slurry within the hose.

In order to compare the performance of the prior art hose 100 shown in Fig. 1 and the hose 200 shown in Fig. 2, both hoses were modeled and simulations of their performance were performed. The results of these simulations are shown in Fig. 3.

Fig. 3 shows the non-uniformity of the flow exiting the right and left sub-sections in both the prior art hose 100 and the hose 200 shown in Fig. 2. In calculating the non-uniformity of the flow rate, the flow rate through each sub-section was calculated using the equation given below:

where u _t is the local velocity transverse to the cross-sectional area, and Ω is the integration domain of the cross-section. The right/left flow non-uniformity was then determined as the percentage difference between the flow rates in the left and right subsections.

As can be seen from Fig. 3, the numerical model was able to reproduce the results observed during use of the prior art hose 100 and the hose 200 shown in Fig. 2. Since the baseline model was successfully created, a parametric study was conducted to identify the design features of the hose 200 that led to the observed reduction in flow rate non-uniformity.

Parametric study

In the parametric analysis, the prior art hose 100 shown in Fig. 1 was taken as a base case. Various dimensions and design features of the prior art hose 100 were varied individually and sequentially to identify those that influenced the right/left flow non-uniformity of the hose.

During the parametric study, the following design features were identified that affect the heterogeneity of the right/left hose flows.

The first section and the second section are the ratio of the cross-sectional areas

A parametric study showed that the ratio of the cross-sectional area of the first section (A ₁ ) to the cross-sectional area of the second section (A ₂ ) has the greatest influence on the right/left hose flow homogeneity. In these calculations, A ₁ was taken as the total cross-sectional area of the first section. A ₂ was taken as the total cross-sectional area of the second section, in this case the sum of the cross-sectional areas of both hose subsections.

As can be seen from Fig. 4, the improvement in right/left flow non-uniformity can be seen when the ratio of A ₁ to A ₂ reaches one. However, the greatest improvement in right/left flow non-uniformity can be seen when the ratio of A ₁ to A ₂ is two or higher.

The ratio A ₁ to A ₂ has a very strong effect on the right/left flow non-uniformity of the hose and adjusting this ratio alone is sufficient to reduce the right/left flow non-uniformity of the hose to an acceptable level. Based on the analysis of the numerical data, the applicant hypothesizes that the reduced non-uniformity observed with an increase in the ratio A ₁ to A ₂ is due to the creation of a recirculation zone inside the hose. The applicant believes that this recirculation zone destroys the rotational component of the gypsum slurry flow as it enters the hose. This destruction of the rotational component of the fluid flow effectively reduces vortex flows of the gypsum slurry, regardless of its source: either directly from the mixer (as in a mixer with a bottom outlet) or as a result of the use of a container (as in a mixer with a tangential outlet). Thus, increasing the ratio of A ₁ to A ₂ improves the uniformity of the flow leaving the hose for both the tangential outlet mixer and the bottom outlet mixer.

The first section and the third section are the ratio of the cross-sectional areas

The parametric study also showed that the ratio of the cross-sectional area of the first section (A ₁ ) to the cross-sectional area of the third section (A ₃ ) also affects the right/left flow homogeneity of the simulated hose. In these calculations, A ₁ was again taken as the total cross-sectional area of the first section. In addition, A ₃ was taken as the total cross-sectional area of the third section.

The parametric study showed, as illustrated in Fig. 5, that an improvement in the right/left flow uniformity of the simulated hose is observed when the ratio of A ₁ to A ₃ reaches one. A more significant improvement in the right/left flow uniformity of the simulated hose can be seen when the ratio of A ₁ to A ₃ is in the range of two to three. Finally, the numerical simulations performed showed that the right/left flow uniformity of the simulated hose decreased again as soon as the ratio of A ₁ to A ₃ exceeded four.

While the adjustment of the ratio A ₁ to A ₃ has a strong effect on the right/left flow homogeneity of the hose, the adjustment of this ratio is not as significant as the adjustment of the ratio A ₁ to A ₂ . Based on the analysis of the numerical data, the applicant hypothesizes that the changes in the right/left flow non-uniformity observed with the adjustment of the ratio A ₁ to A ₃ are the result of changes in the recirculation observed in the hose elbow. As already indicated, the gypsum slurry entering the hose from the container of the tangential mixer has a rotational component in its flow. The same is true if the gypsum slurry enters the hose directly from the mixer with a bottom outlet.

If A ₃ is less than A ₁ or has the same value as A ₁ , the gypsum slurry flow creates vortex flows when it encounters the restriction of the third section. Within the range highlighted in Fig. 5, the applicant believes that this vortex flow effectively counteracts the rotational component of the gypsum slurry when it enters the restriction, resulting in a balanced flow. If the ratio of A ₁ to A ₃ increases beyond that highlighted in Fig. 5, the right/left flow non-uniformity increases again, presumably due to the large change in cross-sectional area upon entry into the third section, introducing its own rotational component into the flow.

Knee - outer radius of curvature

Some embodiments of the present invention include an elbow or transition section that either (1) connects the first section to the second section if there are only two sections, or (2) connects the first section to the third section if there are three sections. In these embodiments, the elbow has a direct effect on the right/left flow non-uniformity of the hose.

The shape of the knee and the transition section between the first section and the third section can be described by the outer radius of curvature R _Ex of the knee. The outer radius of curvature of the knee is measured as the maximum radius of curvature of the knee, as shown in Fig. 6.

In cases where an elbow was present, a parametric study showed that varying R _Ex could improve the right/left flow homogeneity. These results are also illustrated in Fig. 6. If the first section was taken as having the longest internal dimension in the plane perpendicular to its longitudinal axis d ₁ , numerical simulations were performed showing that improvements in the right/left flow non-uniformity were observed when R _Ex was equal to half of d ₁ . Numerical simulations showed that these improvements remained valid when R _Ex was equal to twice d ₁ , before decreasing. These obtained results are illustrated in Fig. 6.

Again, the numerical model illustrates that adjusting R _Ex relative to d ₁ affects the right/left hose flow homogeneity. However, this effect is less pronounced than either changing the ratio of A ₁ to A ₂ or changing the ratio of A ₁ to A ₃ . Furthermore, the applicant's analysis suggests that adjusting R _Ex relative to d ₁ does not affect the right/left hose flow non-uniformity unless adjusting the ratio of A ₁ to A ₂ has already created a recirculation zone in the hose.

Numerical simulations carried out by the applicant suggest that the improvement in right/left flow non-uniformity observed in the range

is due to the increase in the recirculation zone inside the hose. This increase in the recirculation zone ensures that the rotational component of the gypsum solution flow entering the hose is destroyed before the gypsum solution reaches the second section, which improves the homogeneity of the flow.

Aspects, embodiments and design features of the present invention may also be defined by the following statements.

1. A hose for use in the production of a gypsum mortar building product, comprising: a first section having a cross-sectional area A ₁ , and a second section having a cross-sectional area A ₂ , wherein said first section is hydraulically connected to said second section, wherein in use the first section is located upstream of said second section, wherein A ₁ is at least twice as large as A ₂ .

2. A hose according to statement 1, in which the A ₂ is not more than four times greater.

3. A hose according to claim 1 or claim 2 comprising a third section having a cross-sectional area _A3 located between said first section and said second section.

4. A hose according to statement 3, in which A ₁ is equal to or greater than A ₃ .

5. A hose according to statement 3 or statement 4 in which A ₁ is not more than four times greater than A ₃ .

6. A hose according to any one of statements 3-5, wherein the longitudinal axis of said first section lies generally perpendicular to the longitudinal axis of said third section.

7. A hose according to any of statements 1-2, wherein said first section is connected to said second section by means of an elbow.

8. A hose according to any one of statements 3-6, wherein said first section is connected to said third section by means of an elbow.

9. A hose according to claim 8, wherein said first section has its greatest dimension in a plane perpendicular to its longitudinal axis, and wherein said elbow has an outer radius of curvature equal to at least half of d ₁ .

10. A hose according to statement 9, in which the outer radius of curvature of said elbow is not more than twice d ₁ .

11. A hose according to any of the preceding statements, wherein said second section comprises at least two subsections, the total cross-sectional area of said subsections being equal to A ₂ .

12. The hose according to claim 11, wherein the cross-sectional area of each subsection in a plurality of subsections is substantially the same.

13. A method for manufacturing a gypsum product, comprising the steps of

mix the gypsum solution in a mixer,

removing said gypsum solution from said mixer through a hose according to any of statements 1-12 onto a molding table,

harden the specified gypsum solution.

14. A method for dispensing a gypsum solution, including providing a hose with a plurality of distribution sections, wherein the hose comprises at least two sections with corresponding cross-sectional areas A ₁ and A ₂ , wherein the ratio of A ₁ to A ₂ is such that the flow asymmetry in said distribution sections is below 1%.

15. The method according to statement 14, which is a method for dispensing gypsum mortar for the manufacture of a gypsum-based product.

16. The method according to claim 15, comprising the steps of:

provide the presence of a mixer,

provide the presence of a molding table, and

dispense said gypsum solution from said mixer through said hose onto said molding table.

17. The method according to claim 15, wherein said hose is a hose according to any of claims 1-12.

Claims (25)

1. A hose for use in the production of a building product made from gypsum mortar, comprising: a first section having a cross-sectional area A ₁ , and the second section having a cross-sectional area of A ₂ , wherein said first section is hydraulically connected to said second section, wherein in use said first section is located upstream of said second section, where A ₁ is at least twice as large as A ₂ , wherein said hose comprises a third section having a cross-sectional area A ₃ , located between said first section and said second section, wherein said first section is connected to said third section by means of a knee, wherein said first section has a largest dimension d ₁ in a plane perpendicular to its longitudinal axis, and wherein said knee has an outer radius of curvature equal to at least half of d ₁ , characterized in that the longitudinal axis of said first section lies perpendicular to the longitudinal axis of said third section and the longitudinal axis of said second section, and the longitudinal axis of said second section lies parallel to the longitudinal axis of said third section. 2. A hose according to item 1, wherein A ₁ is no more than 4 times greater than A ₂ . 3. A hose according to claim 1 or 2, wherein A ₁ is equal to or greater than A ₃ . 4. A hose according to any of the preceding claims, wherein A ₁ is not more than four times greater than A ₃ . 5. A hose according to any of the preceding claims, wherein the outer radius of curvature of said elbow does not exceed a value equal to twice d ₁ . 6. A hose according to any one of the preceding claims, wherein said second section comprises at least two subsections, the total cross-sectional area of said subsections being equal to A ₂ . 7. The hose of claim 6, wherein the cross-sectional area of each subsection in the plurality of subsections is the same. 8. A method for manufacturing a gypsum product, comprising the steps of mix the gypsum solution in a mixer, remove said gypsum solution from said mixer through a hose according to any of paragraphs 1-7 onto a molding table, harden the specified gypsum solution. 9. A method for dispensing a gypsum solution for the manufacture of a gypsum-based product, which includes providing a hose according to any one of paragraphs 1-7, wherein the method comprises the steps of: provide the presence of a mixer; provide the presence of a molding table, and dispense said gypsum solution from said mixer through said hose onto said molding table.