JP2007147102A - Determining method for duct size - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of duct sizes to be used, and the number of necessary members following it, when constructing a duct. <P>SOLUTION: For example, after carrying out primary setting of duct sizes by an equal friction method, its total pressure loss is determined to set a total pressure loss design desired value. The maximum number of types of ducts with different sizes to be used is determined beforehand, and the primarily set respective duct sizes are replaced by the sizes of the duct of plural types determined beforehand. Then, a whole of a set duct module A of the largest size to be installed in a blower side is changed to that of a one rank smaller size, its total pressure loss is calculated, and the size of a unit duct or the set duct module of the blower side is sequentially changed until the total pressure loss approximates to the total pressure loss design desired value in the calculation result. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for determining a duct size for air conditioning.

  Conventionally, the “equal friction method” has been widely adopted as a method for determining the size of a duct to be used at the design stage in advance of constructing the duct (see Non-Patent Document 1). The “equal friction method” determines the duct size so that the friction loss per unit length of the duct is constant.

  Moreover, on the premise of the above equal friction method, furthermore, in order to equalize the pressure loss to the terminal air vents of all the branch air ducts, the farthest part of each of the furthest part of the branch duct from the branch duct to the basic duct path and the branch duct path A method has been proposed in which the distance to the air control port is measured, a correction value is obtained therefrom, and the duct size is determined by multiplying the pressure loss value obtained by the equal friction method by the correction value (see Patent Document 1).

Air Conditioning and Sanitary Engineering Association “Air Conditioning Sanitary Engineering Handbook 3 Air Conditioning Equipment Design 315p” (Japan) Air Conditioning and Hygiene Engineering Society 1995 Japanese Patent Laid-Open No. 10-82549

However, in the equal friction method, it is necessary to prepare many different sizes of ducts, and accordingly, many members for connecting ducts having different diameters called hoppers are required. As a result, it took time and effort for design and construction, and it was a cause of high cost.
On the other hand, although the thing of patent document 1 has the effect that the pressure loss to all the air vents of the end of a duct system is equal, the problem seen with an equal friction method still remains. .

  The present invention has been made in view of the above points, and the number of ducts to be used is reduced, thereby reducing the number of necessary hoppers, thereby determining the duct size that is easier to design and construct than before. It aims to provide a way to do that.

The total pressure loss of the duct is a set of friction losses including local resistance and blowout dynamic pressure, reducing the friction loss at the end of the duct, that is, the small air volume region, and increasing the friction loss at the beginning of the duct, that is, the large air volume region accordingly. Even if it is done, the same total pressure loss will result.
On the other hand, economically, increasing the duct size in the small airflow area has less impact on the price than increasing the duct size in the large airflow area. In other words, the price reduction effect by reducing the duct size in the large air volume region is higher than the price reduction effect by reducing the duct size in the small air volume region.
The thickness of the steel plate used for the duct is determined by the long side dimension of the duct. The price sensitivity to the amount of iron plate used by small size ducts is slow. The reason is that the influence of both material cost and processing cost is small. Therefore, the duct size per pressure loss is the lowest for the maximum size duct of the small size duct that can use the same plate thickness.
In addition, the price per iron plate usage of large size ducts is higher than that of small size ducts, so it is important to reduce the area of large size ducts.
The present invention provides a rational method for determining the duct size from such a viewpoint. Note that the size of the duct means the size of the diameter in the case of a round duct, and the size of long side × short side in the case of a square duct.

  In order to achieve the above object, according to the present invention, a predetermined pressure loss per unit length is first used as a first criterion for duct size determination. This is determined by the designer at the time of design, for example, 1 mmAq / m. Based on this, the duct size is primarily set, the total pressure loss is obtained, and this is determined as the total pressure loss design target value. For the primary setting, for example, a known equal friction method may be used. This “primary setting” is shown in design drawings and other design documents. Before starting construction, the duct route and duct size are reviewed from the standpoint of fit and other aspects, but the design target value of pressure loss is generally kept as it is.

  Next, the maximum number of types of ducts of different sizes to be used is determined in advance in a range smaller than the number of the primary set ducts. For example, this is arbitrarily determined by comprehensively taking into account the situation of the site to be constructed, the degree of fit, and the available ducts. Then, the primary set size of each duct is replaced with the predetermined duct size collective duct module within a range not exceeding a predetermined pressure loss per unit length. Here, “replacement” means standardizing the duct, and so to say, a header-like duct is formed. For example, when the ducts of 10 different sizes of 1 to 10 are primarily set by the existing equal friction method, the number of ducts is changed to a smaller number, for example, 4 or less. When changing, the position where the friction loss becomes the pressure loss friction loss per unit length (reference friction loss value) determined as the first reference is obtained from the end duct, and this reference friction loss value is sequentially calculated. Replace with 4 types of ducts as long as they do not exceed. At this point, the total pressure loss (temporary pressure loss) of the ducts replaced with the four types is smaller than the total pressure loss design target value. The collective duct module refers to a unit constructed by extending a plurality of unit ducts having the same length.

Next, change the entire duct module of the largest size (large passing air volume) to be installed on the blower side to one rank smaller, calculate the total pressure loss at that time, and based on the calculation result Then, any one of the following (1) to (3) is performed.
Such processing is actually performed using, for example, a personal computer. Therefore, for example, when processing is performed consistently with CAD input from a design drawing, internal data is used. Except for special cases such as air supply that merges from a plurality of fans installed in parallel, the duct installed on the fan side may be regarded as a duct having a large passing air volume. When the merging point from a plurality of blowers is a unit duct with the longest circumference (diameter), the duct is the “largest unit duct to be installed on the blower side”.

  In the present invention, the meaning of total pressure loss design target value≈total pressure loss means that the total pressure loss is within an error range of ± 10% of the total pressure loss design target value.

(1) When the total pressure loss design target value ≈ total pressure loss, the size of each duct at that time is determined as the adopted duct size.
(2) If the total pressure loss design target value is less than the total pressure loss, the unit duct constituting the largest-sized collective duct module at that time is changed to one that is one rank larger from the blower side. Calculate the loss and repeat the process until the total pressure loss design target value ≒ total pressure loss.
(3) If the total pressure loss design target value is greater than the total pressure loss, the total duct loss module of the largest size at that time is changed to one that is one rank smaller, and the total pressure loss is calculated.
(3-1) If the total pressure loss design target value ≈ total pressure loss, the size of each duct at that time is determined as the adopted duct size.
(3-2) When the total pressure loss design target value <the total pressure loss, the process (2) is performed.
(3-3) If the total pressure loss design target value> total pressure loss, the process of (3) is repeated until the total pressure loss design target value≈total pressure loss.

  By performing such a process, it is possible to determine the duct size of the total pressure loss that is smaller than the duct that has been initially set, and that is almost equal to the total pressure loss design target value.

  In the above, the entire largest duct module on the blower side of the primary set duct is temporarily changed to a size smaller by one rank. However, as described below, the largest duct module on the blower side of the primary set duct is the largest. In the large collective duct module, the size of the unit duct closest to the end may be reduced by one rank.

  That is, according to another aspect of the present invention, the sizes of individual ducts set primarily may be set to the predetermined plural types within a range not exceeding the first reference, that is, a predetermined pressure loss per unit length. After replacing the duct with the size of the unit duct, the unit duct on the end side constituting the largest-sized collective duct module to be installed on the blower side is first changed to one smaller in rank (ie, the “unit duct” (Reducing the size in units) and calculating the wind speed at that time (hereinafter referred to as “pre-processing”). And based on the said calculation result, the following A or B process is performed and it repeats until the employ | adopted duct size is determined.

  The wind speed is calculated for correction. In other words, even if the isofriction method is designed to be, for example, 1.0 Pa / m, the friction loss varies as the air volume increases or the wind speed increases. Therefore, if such correction is not performed, for example, the duct may vibrate even if it is constructed as designed.

A. When the calculation result of the pre-processing is equal to or less than the upper wind speed, the total pressure loss is calculated, and any one of the following (1) to (3) is performed based on the calculation result. Here, the upper limit wind speed refers to the wind speed determined in advance based on the size of the duct, and refers to the maximum wind speed at which vibration or the like does not occur in the duct.
(1) If the total pressure loss design target value ≈ total pressure loss, the size of each duct at that time is determined as the adopted duct size.
(2) If the total pressure loss design target value <total pressure loss, the size of each duct at that time is determined as the adopted duct size.
(3) If the total pressure loss design target value is greater than the total pressure loss, check whether there is still a unit duct that constitutes the collective duct module in the collective duct module of the largest size at that time.
(3-1) If there is no longer any remaining unit duct, the size of the duct installed at the most blower side at that time is lowered by one rank, and the presence / absence of a duct of a lower rank size is checked. as a result,
(3-1-1) If there is no duct of the lower rank size, the size of each duct at that time is determined as the adopted duct size.
(3-1-2) If there is a unit duct of the lower rank size, change the unit duct on the terminal side in the collective duct module after the rank has been lowered by one rank to a smaller one The wind speed is calculated, and the process returns to A above.
And, as a result of examining whether there is a remaining unit duct of the process (3),
(3-2) If unit ducts still remain, change the unit duct located at the most distal side among the remaining unit ducts to one that is one rank smaller, and calculate the wind speed at that time. Thereafter, the process returns to A.

  B. When the calculation result of the wind speed in the above-described pre-processing exceeds the upper limit wind speed, all of the sizes when the replacement with the collective duct module of the plurality of predetermined sizes of ducts are temporarily returned to the fan side at that time. Of the unit ducts that make up the next-largest size collective duct module to be installed, change the unit duct at the end most to one that is one rank smaller, calculate the wind speed at that time, and Return to process A.

  By following such a procedure, the duct size of the total pressure loss can be determined with fewer types of ducts to be used than the finally set ducts and substantially equal to the total pressure loss design target value.

  As described above, in the present invention, the largest duct size is sequentially changed so as to approach the total pressure loss design target value based on the preset primary setting, and the total pressure loss at that time is the total pressure loss. Since the duct size is determined so as to approach the design target value, the type of duct size to be used can be reduced as compared with the conventional one. Therefore, the number of duct sizes to be used can be reduced as compared with the conventional case, and the number of necessary hoppers is reduced. Therefore, design and construction are easier than before.

  Hereinafter, a preferred embodiment of the present invention will be described. FIG. 1 shows a process flow for determining a duct size according to the first embodiment. In reality, it is preferable that all or a part of these be performed by a computer such as a personal computer appropriately provided with input means such as a keyboard and mouse, display means such as a display device, and printing means in addition to the arithmetic unit. It is. First, a friction loss per unit length (hereinafter referred to as “reference friction loss value”) as a first reference is set (step S1). For example, a reference friction loss value is set such as 1 mmAq / m. In such a case, the wind speed per unit length may be set in consideration of the duct route.

  For example, when a construction drawing is created by reexamining a design drawing and the route is changed, the following calculation is performed for the route after the change. “Air volume” is the amount of air supplied (exhaust) to the duct system, and is usually the sum of the air volume at the outlet (suction port) of the route system and the air volume of the blower (exhaust air). This air volume is set (input) here because it is used for wind speed calculation described later.

  Next, the duct size is obtained based on the reference friction loss value per unit length determined in step S1, and the pressure loss of the entire route of the duct to be constructed is obtained, and this is set as the “total pressure loss design target value” ( Step S2). Such treatment is no different from the conventional isofriction method. This value does not necessarily have to be calculated each time by a computer, and may be used as it is if it is determined by a design drawing or the like. As a result, the duct size is set primarily. The image of the duct size set primarily is shown in FIG.

In FIG. 2, there are ten types of ducts A to J, for example, in the duct size set primarily. Note that hoppers 1 to 9 are arranged between the ducts even in the design stage. Also, in FIG. 2, the main duct is illustrated in a simplified manner among the duct routes that are subjected to calculation using the present invention. However, in practice, branch ducts are appropriately branched from the respective duct pieces (corresponding to unit ducts) A to J, and communicated with the air outlet (intake port when this duct system is an exhaust duct). In fact, the main duct may be bent, raised or lowered, but is shown as a straight line for convenience of explanation. A plurality of these duct systems are constructed in the building, and the calculation processing described later is performed for each duct system.

Next, n types of duct sizes to be used are selected with the above-mentioned reference friction loss value as an upper limit (step S3). For example, it is arbitrarily selected in consideration of the situation of the site to be constructed, the degree of fit, available ducts, cost, etc. For example, in the present embodiment, the following four types of ducts A, B, E, and G, which are square ducts, are selected and the types are collected. The brackets indicate the plate thickness.
A. 1200 × 300 (0.8mm)
B. 1000x300 (0.8mm),
E. 750x300 (0.6mm),
G. 450x300 (0.5mm),
That is, the size of each duct is duct A> duct B> duct E> duct G. By this consolidation, the ducts C and D before consolidation shown in FIG. 2 are aggregated into the duct B after consolidation, the duct F before consolidation is merged with the duct E after consolidation, and the ducts H, I, and J before consolidation are aggregated. Each of the sizes is replaced by the subsequent duct G.

  As described above, in this embodiment, since four types of duct sizes are selected, x in the flow of FIG. 1 is x = 4. For the convenience of explanation, the sizes of the selected ducts A, B, E, and G are selected from the ducts A to J of the duct size shown in FIG. 2 which are primarily set. Of course, the individual ducts to be selected are primarily set. There is no need to select from the selected duct size.

  Then, the primary set duct size shown in FIG. 2 is replaced with the selected four types of ducts A, B, E, and G. In replacement, first, replacement processing is performed from the end of the duct (in the case of FIG. 2, replacement is performed in order from the smallest duct G, which is located closest to the end, in order from the smallest duct G). In the replacement, the position (boundary position where the duct size changes) where the friction loss becomes the reference friction loss value (for example, 1 Pa / m as described above) is obtained, and the duct is set primarily within the range not exceeding the reference friction loss value. J to A are replaced with the selected ducts G, E, B, A. If the total pressure loss of the replaced ducts A, B, E, G is “temporary pressure loss”, the unit Ducts A, B, E, and G, which are aggregates of ducts, employ the largest unit duct size among them, so that the result is the standard friction loss value> temporary pressure loss. Same An assembly in which unit ducts of a size are connected and extended through connectors such as appropriate flanges, packings, and joints is called an assembly duct module.

  The replaced ducts A, B, E, and G are collective duct modules each of which is a set of unit ducts. In the present embodiment, as shown in FIG. 3, for example, the collective duct module A is composed of unit ducts A1 and A2, and the collective duct module B is composed of unit ducts B1, B2, B3, and B4. The module E is composed of unit ducts E1, E2, and E3, and the collective duct module G is composed of unit ducts G1, G2, G3, G4, and G5. A standard object can be used. The standard length is about 1.74m according to the Ministry of Land, Infrastructure, Transport and Tourism standards, but recently, the standard is about 1.13m. These depend on the roll width of the iron plate when manufacturing the duct.

  Next, a flag is set to process sequentially from n = 1, which means the largest duct among the initially selected x = 4 (step S4). Then, the entire largest aggregate duct module A to be installed on the blower side is changed to one rank smaller aggregate duct module B, and the total pressure loss at that time is calculated (step S5). FIG. 4 shows an image in which the entire largest size of the collective duct module A is changed to the collective duct module B which is one rank smaller. At this time, the collective duct module B is constituted by unit ducts B1 to B6.

The pressure loss of the entire assembly duct module A after changing the entire assembly duct module A to an assembly duct module B smaller by one rank (the entire duct from the duct H to the unit duct B6, for example, the entire system from the blower to the outlet) is expressed as “ When calculated as “primary total pressure loss” and compared with “total pressure loss design target value”, the following three types are obtained.
(1) “Total pressure loss design target value” ≒ “Primary total pressure loss” (calculation result)
(2) “Total pressure loss design target value” <“Primary total pressure loss” (calculation result)
(3) “Total pressure loss design target value”> “Primary total pressure loss” (calculation result)

  In actual processing, first, it is checked whether “total pressure loss design target value” ≈ “primary total pressure loss” (step S6), and “total pressure loss design target value” ≈ “primary total pressure loss”. In this case, the process is terminated at that time, and the size of each duct at that time is determined as the adopted duct size (step S7). That is, the design is completed in the state of FIG.

  On the other hand, if “total pressure loss design target value≈primary total pressure loss” is not satisfied in step S6, it is checked whether “total pressure loss design target value” <“primary total pressure loss” (step S6). S11). In the case of “total pressure loss design target value” <“primary pressure loss”, the largest size of the collective duct module B at that time is set to 1 for each unit duct Bx constituting the collective duct module B from the blower side. The pressure is changed to a higher one, and the total pressure loss is calculated each time (step S12). According to the state of FIG. 4, among the unit ducts B1 to B6 constituting the largest collective duct module B at that time, the size is increased by one size in order from the unit duct B6 with the largest passing air volume from the blower. Instead of the unit duct Ax, the total pressure loss is calculated each time. FIG. 5 shows a state in which the unit duct B6 from the blower is raised to a unit duct A1 that is one size larger. This process is repeated until “total pressure loss design target value ≈ primary total pressure loss”, and when “total pressure loss design target value ≈ primary total pressure loss” is reached, the process ends. The duct size at that time is determined as the adopted duct.

  If “total pressure loss design target value”> “primary total pressure loss” in the previous step S11, the entire size of the collective duct module having the largest size at that time is changed to one lower in rank and the total pressure is reduced. Calculate the loss. In other words, n = n + 1 (meaning that it is the second largest among the initially selected x = 4) is changed (step S21), the process returns to step S5, and is changed to one that is smaller by one rank to reduce the total pressure loss. calculate. Speaking from the state of FIG. 4, since the duct of the largest size in the state of FIG. 4 is the collective duct module B, the entire collective duct module B is changed to a collective duct module E that is one rank smaller, Calculate pressure loss. FIG. 6 shows an image in which the entire collective duct module B is changed to a collective duct module E that is one rank smaller. At this time, the collective duct module E is constituted by unit ducts E1 to E9.

And as a result of calculating the total pressure loss,
(3-1) When the total pressure loss design target value≈total pressure loss, the size of each duct at that time is determined as the adopted duct size (step S6, step S7).
(3-2) If the total pressure loss design target value is less than the total pressure loss, then change the largest size of the collective duct module E at that time to one larger in rank from the blower side for each unit duct Ex. Each time, the total pressure loss is calculated (step S12). According to the state of FIG. 6, among the unit ducts E1 to E9 constituting the largest collective duct module E at that time, the unit duct Bx that is one size larger is arranged in order from the unit duct E9 from the blower. Instead, the total pressure loss is calculated each time. FIG. 7 shows a state in which processing is performed in order from the unit duct E9, and the unit ducts E8 and E7 are changed to unit ducts B1, B2, and B3 each having one rank and a large size. In this state, if the total pressure loss design target value ≈ total pressure loss, the process is terminated, and the duct size at that time is determined as the adopted duct.

  On the other hand, when (3-3) Total pressure loss design target value> Total pressure loss is still reached at the time of FIG. 6, this time, the entire collective duct module E is changed to the collective duct module G whose size is one rank smaller. Thereafter, the above processing is repeated until the total pressure loss design target value≈total pressure loss.

  According to the first embodiment described above, for example, in any state of FIGS. 4 to 7, the adopted duct size is adopted even if the total pressure loss design target value ≒ total pressure loss processing is completed and the design processing ends. Compared to the primary duct size shown in Fig. 2, the type of duct size to be used can be reduced from that of Fig. 2, and the number of thick ducts is reduced and necessary. The number of hoppers is also decreasing. Therefore, it is easier to design and construct at a lower cost than before. By preparing the types of ducts to be used in advance and standardizing them, material management is easy and construction of ducts with extremely low costs can be realized. Note that the order in which the determinations in steps S6 and S11 are processed may be reversed. In step S11, the designator is set to “design value> calculated value”. If Yes, the process in step S21 is performed. If No, the process in step S12 is performed. Processing may be performed.

  In the first embodiment described above, the entire largest collective duct module on the blower side of the duct initially set is temporarily changed to a size smaller by one rank, but the second embodiment described below is used. As in the above embodiment, the size of the unit duct closest to the end may be reduced by one rank in the entire collective duct module having the largest passage air volume of the duct set primarily and having the largest fan side.

  FIG. 8 shows the flow of the second embodiment. Steps S50 to S54 are the same as steps S0 to S4 of the first embodiment. For example, the duct set primarily in step S52. The size is as shown in FIG. 2 as in the first embodiment, and the state of selecting the type of duct to be used is as shown in FIG. 3 as in the first embodiment.

  Then, in the second embodiment, from the state of FIG. 3, firstly, the largest size of the collective duct module (n = 1) to be installed on the blower side, which has the largest passing air volume, is constructed. For example, the unit duct on the end side when the air volume is small as viewed from the blower side is changed to one (n + 1) smaller by one rank (step S55). According to the state of FIG. 3, the largest size duct to be installed on the blower side is the duct A, and the unit ducts A1 and A2 constituting the duct are the farthest from the blower (on the end side). ) Change the unit duct A1 to a duct B of a size smaller by one rank. That is, the unit duct B5 is changed to a size smaller by one rank. The image after the change is shown in FIG. Therefore, at this time, the collective duct module B is constituted by the unit ducts B1 to B5.

Next, in this embodiment, the duct wind speed is checked in consideration of duct vibration and the like. For example, in buildings such as theaters and broadcast stations where the effect of vibration is large, it is forbidden to reduce the duct size that causes an increase in wind speed. Also, in general buildings, the reduction of the duct size leads to an increase in the wind speed, and the air supplied from the terminal outlet may give the occupants a draft, so it is desirable to check the wind speed.
Then, the wind speed of the duct at that time is calculated from the given air volume and the determined duct size, and compared with the upper limit wind speed (design value, given condition, in this case 8.0 m / sec) (step S56). If the calculated value is less than or equal to the upper limit value, the total pressure loss is calculated (step S57), and compared with the total pressure loss design target value, whether or not the total pressure loss design target value ≈ total pressure loss (calculated value). Is examined (step S58). As a result, if the total pressure loss design target value≈total pressure loss, the size of each duct at that time is determined as the adopted duct size, and the process ends (step S59). That is, the state of FIG. 9 is the adopted duct size.

  In step S58, if the total pressure loss is not within the allowable range of the total pressure loss design target value, it is checked whether the total pressure loss design target value is less than the total pressure loss (step S61). If value <total pressure loss, the size of each duct at that time is determined as the adopted duct size. That is, also in this case, the state of FIG. 9 is the adopted duct size. This is because the unit duct is adjusted to the largest one in the collective duct module and the wind speed is checked, so that even if it exceeds 10% of the total pressure loss design target value, it is acceptable. Unlike the elbow and hopper, the straight pipe member has low resistance, and even if the error is 10%, the increase in pressure loss is less than 1%.

  On the other hand, as a result of step S61, if the total pressure loss design target value> total pressure loss, it is checked whether there is still a remaining unit duct in the collective duct module having the largest size at that time (step S71). According to FIG. 9, it is checked whether or not the largest collective duct module A still has a unit duct Ax constituting it. If the unit duct Ax still remains, the unit duct located on the most distal side among the remaining unit ducts Ax is changed to one smaller by one rank and subjected to calculation. That is, in accordance with FIG. 9, the wind speed is calculated after the unit duct A2 is reduced in size to B (step S55). The same processing is performed after step S56.

  If the result of the determination in step S71 is that there is no remaining unit duct in the largest-sized collective duct module at that time, the size of the collective duct module installed on the blower side at that time is lowered by one rank ( Step S72). Then, the presence / absence of a smaller-sized collective duct module than the collective duct module lowered by one rank is checked (step S73). That is, in the state of FIG. 10, it is checked whether or not there is a smaller collective duct module than the collective duct module B. In other words, it is examined here whether the collective duct module attached to the judgment has the same size from end to end of the main duct.

If there is no collective duct module smaller than the collective duct module B, the size of each duct at that time is determined as the adopted duct size (step S74). Since the previous process is lower than the design value, even if it exceeds this value, it does not deviate from the error range.
If there is a collective duct module smaller than collective duct module B (in FIG. 10, collective duct module smaller than collective duct module B is E), the process returns to step S55, and collective duct module B is configured hereinafter. Among the unit ducts B1 to B6, the unit duct B1 on the end side is changed to a size smaller by one rank, the wind speed at that time is calculated, and the process proceeds to step S56. FIG. 11 shows a state where the unit duct B1 on the end side is changed to a unit duct E4 having a size one rank smaller. When the total pressure loss design target value ≦ total pressure loss is not satisfied, the next end unit duct B2 is lowered by one rank and changed to a unit duct E5. FIG. 12 shows a state in which the rank is lowered by one rank from the end side to the third unit duct B3 in the collective duct module B in this way.

  On the other hand, in step S56, the wind speed was checked. If the calculated value at that time exceeded the design value, the entire duct was temporarily returned to the original size (step S81, returning to the state shown in FIG. 3). A size reduction is attempted with a small collective duct module (collective duct module B in FIG. 3) (step S82). In other words, it abandons the thinning of the thickest duct module A, and then tries to move the thicker duct module B to the size E.

  Note that the wind speed check routine in step S55 may be after the routine for comparing the total pressure loss values, not after. That is, it may be performed immediately before steps S59, S62, and S74.

  Thus, also in the second embodiment, as in the first embodiment, the adopted duct size is the kind of duct size to be used as compared with the duct size of FIG. 2 can be reduced as compared with FIG. 2, and the number of thick ducts is reduced, and the number of hoppers required is also reduced. Therefore, it is easier to design and construct at a lower cost than before. By preparing the types of ducts to be used in advance and standardizing them, material management is easy and construction of ducts with extremely low costs can be realized. Moreover, since the wind speed is checked, higher quality equipment can be realized.

  In each of the above embodiments, the duct size to be used is, for example, four types (ducts A, B, E, and G), and after replacing them, the collective duct modules A, B, E, and G are configured. An appropriate duct size is determined by adjustment and calculation for each unit duct to be performed (steps S12 and 55). However, the present invention is not limited to this. For example, a table of standardized unit duct sizes is prepared (for example, a computer). Or may be adjusted and calculated by selecting from the table.

  That is, for each duct size of the unit duct, the air volume, wind speed, unit friction loss, duct plate thickness, and allowable maximum wind speed data are stored in a suitable storage medium as a table. When the duct size is enlarged or reduced, if it is selected from this table, the duct material can be more standardized and management can be improved. For example, joints such as hoppers and elbows that are limited to those related to the table can be stocked.

  In addition, when the above table is prepared, when replacing the primary set duct with the duct size to be used, the size is not selected from the primary set ducts, but the collective duct by the unit duct described in the table is used. Modules can be configured and selected from among them, more appropriate duct sizes can be determined, and duct materials can be standardized to facilitate management.

  Of course, the present invention is applicable not only to a square duct but also to a circular duct. For convenience of explanation, the transition of the duct size is shown sequentially. However, when the computer actually executes a series of processing, it is not necessary to display the status on the screen every time the computer is replaced or changed. Such is not related to the essence of the present invention. Therefore, for example, the parameters of step S1 and step S51 and the specifications of the members connected to the duct route are input to the spreadsheet software, and the members changed by calculation and their sizes are displayed in different colors on the input sheet. Good.

  The present invention is useful in the design stage when constructing ducts.

It is a flowchart which shows the process of the duct size determination method concerning 1st Embodiment. It is a side view which shows the image of the duct size after primary setting. It is a side view which shows the state after replacing the duct size of FIG. 2 with the selected kind of duct. FIG. 4 is a side view showing a state where the size of the entire collective duct module on the largest blower side is reduced by one rank from the state of FIG. 3. FIG. 5 is a side view showing a state in which a unit duct on the largest blower side is enlarged by one rank from the state of FIG. 4. FIG. 5 is a side view showing a state where the size of the entire collective duct module on the largest blower side is reduced by one rank from the state of FIG. 4. It is a side view which shows the state which enlarged the unit duct by the side of the largest air blower one rank at a time from the state of FIG. It is a flowchart which shows the process of the duct size determination method concerning 2nd Embodiment. FIG. 4 is a side view showing a state where the size of the largest end-side unit duct is reduced by one rank from the state of FIG. 3. FIG. 10 is a side view showing a state where the size of the largest end-side unit duct is reduced by one rank from the state of FIG. 9. It is a side view which shows the state which reduced the size of the largest unit duct of the largest terminal side 1 rank from the state of FIG. FIG. 12 is a side view showing a state in which the size of the largest end-side unit duct is sequentially reduced by one rank from the state of FIG. 11.

Explanation of symbols

1-9 Hopper A-J Duct A1-A2, B1-B6, E1-E9, G1-G5 Unit Duct

Claims (2)

In the method of determining the size of individual ducts used for duct piping to be constructed,
Determining the total pressure loss design target value by first setting the size of each duct based on a predetermined pressure loss per unit length of each duct, and determining the total pressure loss at that time;
Pre-determining a maximum number of different sized duct types to be used in a range that is less than the number of primary set ducts;
Replacing the primary set size of the individual ducts with a set of ducts having a plurality of predetermined sizes within a range not exceeding a predetermined pressure loss per unit length;
Next, the entire largest collective duct module to be installed on the blower side is changed to one smaller in rank, and the total pressure loss at that time is calculated. Based on the calculation result, the following (1) A method for determining a duct size, characterized in that any one of (3) is performed.
(1) When the total pressure loss design target value ≈ total pressure loss, the size of each duct at that time is determined as the adopted duct size.
(2) If the total pressure loss design target value is less than the total pressure loss, the unit duct constituting the largest-sized collective duct module at that time is changed to one that is one rank larger from the blower side. Calculate the loss and repeat the process until the total pressure loss design target value ≒ total pressure loss.
(3) If the total pressure loss design target value is greater than the total pressure loss, the total duct loss module of the largest size at that time is changed to one that is one rank smaller, and the total pressure loss is calculated.
(3-1) If the total pressure loss design target value ≒ total pressure loss, the size of each duct at that time is determined as the adopted duct size.
(3-2) If the total pressure loss design target value is less than the total pressure loss, perform the process (2) above.
(3-3) If the total pressure loss design target value> total pressure loss, the process of (3) is repeated until the total pressure loss design target value≈total pressure loss. In the method of determining the size of the individual ducts used in the duct piping to be constructed,
Determining the total pressure loss design target value by first setting the size of each duct based on a predetermined pressure loss per unit length of each duct, and determining the total pressure loss at that time;
Pre-determining a maximum number of different sized duct types to be used in a range that is less than the number of primary set ducts;
Replacing the primary set size of the individual ducts with a set of ducts having a plurality of predetermined sizes within a range not exceeding a predetermined pressure loss per unit length;
Next, the unit duct on the end side that constitutes the largest-sized collective duct module to be installed on the blower side is changed to one smaller in rank, the wind speed at that time is calculated, and based on the calculation result The method for determining a duct size is characterized in that the adopted duct size is determined by repeatedly performing the following process A or B.
A. When the calculation result is equal to or lower than the upper limit wind speed, the total pressure loss is calculated, and any one of the following (1) to (3) is performed based on the calculation result.
(1) When the total pressure loss design target value ≈ total pressure loss, the size of each duct at that time is determined as the adopted duct size.
(2) If the total pressure loss design target value <total pressure loss, the size of each duct at that time is determined as the adopted duct size.
(3) If the total pressure loss design target value is greater than the total pressure loss, in the collective duct module of the largest size at that time, check whether there are other unit ducts that constitute the collective duct module.
(3-1) If there is no other unit duct anymore, the size of the duct installed at the most blower side at that time is lowered by one rank, and further, the presence or absence of a duct of the size of the lower rank is examined.
(3-1-1) If there is no duct of the lower rank size, the size of each duct at that time is determined as the adopted duct size.
(3-1-2) If there is a duct of the lower rank size, change the unit duct on the end side in the collective duct module after the rank has been lowered by one rank to be one rank smaller. The wind speed is calculated, and the process returns to A above.
(3-2) If unit ducts still remain, change the unit duct located at the end of the remaining unit ducts to one that is one rank smaller, and calculate the wind speed at that time. Hereafter, the process returns to the process A.
B. When the calculation result exceeds the upper limit wind speed, the size is temporarily returned to the size when it is replaced with the collective duct module of the plurality of predetermined sizes of ducts,
Among the unit ducts that will be installed on the blower side at that time and make up the next-largest collective duct module, the unit duct on the end side is changed to one smaller in rank, and the wind speed at that time Then, the process returns to the process A.

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