CN102734220A - Spiral casing for pneumatic extinguisher - Google Patents

Abstract

The invention belongs to the field of forestry machinery, which relates to a spiral casing for a pneumatic extinguisher. The molded line of the spiral casing (A) sequentially comprises a first circular arc line (AB), a second circular arc line (BC) and a third circular arc line (CD) from a helical tongue (A), wherein the first circular arc line (AB) rotates a certain angle clockwise from the tongue (A) to a first intersecting point (B) by taking R as a radius and an impeller (2) as a center, and the angle is smaller than or equal to 180 degrees; the second circular arc line (BC) and the third circular arc line (CD) are drawn as log spirals according to an unequal base circle method; the second circular arc line (BC) adopts an circular arc from the first intersecting point (B) to a second intersecting point (C) with the radius of Ra, and a square corresponding to the circular arc takes a as the side length; and the third circular arc line (CD) adopts a circular arc from the apex (D) of an air inlet to the second intersecting point (C), with the radius Rb, and a square corresponding to the circular arc takes b as the side length. The spiral casing ensures that the power is unchanged, meanwhile solves the problems of the existing pneumatic extinguisher that the fire extinction air speed is low, the fire extinction efficiency is low and the power utility ratio is insufficient, and has great significance for effectively suppressing a fire and reducing the loss brought by the fire.

Description

A kind of Pneumatic extinguisher is used spiral case

Technical field

The invention belongs to the forestry machinery field, relate to a kind of Pneumatic extinguisher and use spiral case, it is used in particular for the grassland Pneumatic extinguisher.

Background technique

Grassland resources is maximum, the main territorial resources of area in China's agricultural natural resource.The grassland has very big value, except that having the economic value that raise livestock increases herdsman's income, also have check winds and fix drifting sand, purify air, water conservation, the multiple ecological value such as prevent erosion, preserve the ecological environment.Prairie fire is to influence the grassland to take place and a key factor that develops.Since founding the state, only grass fire just take place more than 50,000 time in the pastoral area, and the disaster-stricken meadow of accumulative total area reaches more than 200,000,000 hectare, causes more than 600 hundred million yuan of economic losses, reaches more than 10 hundred million yuan every year on average.Now the prairie fire that generally adopts of China equipment of putting out a fire to save life and property is the portable wind-power fire extinguisher, and effective fire extinguishing wind speed is less, the problem of fire extinguishing energy shortage but these small-sized fire extinguishers exist.

Usually, Pneumatic extinguisher mainly is made up of motor and centrifugal blower two-part, and motor is generally the two-stroke gasoline engine of customization, and therefore the research to Pneumatic extinguisher is primarily aimed at the centrifugal blower expansion.Centrifugal blower mainly is made up of impeller and spiral case, because centrifugal blower fan blade wheel manufacturing process cost is higher, only improves fan performance from these aspects the Pneumatic extinguisher price is raise, and be difficult to accepted by market, and potentiality is little.Therefore, research is considered through the design of spiral case being improved the performance of blower fan.

In Pneumatic extinguisher, the effect of spiral case is with the gas channeling spiral case outlet of leaving impeller, and changes the part dynamic pressure into static pressure.The structure of spiral case is the complex spatial curved surface, and in theory, the molded lines of spiral case is a helix.Because spiral case is the critical component of centrifugal blower, the design of spiral case molded lines not only is directly connected to the flow losses in the spiral case, and also the aeroperformance to impeller has very big influence, and it directly influences the performance parameters such as efficient and output flow, pressure of blower fan.

Summary of the invention

To the problems referred to above, the purpose of this invention is to provide a kind of Pneumatic extinguisher and used spiral case, it is guaranteeing under the constant prerequisite of power, has solved the existing Pneumatic extinguisher problem that wind speed is less, fire-fighting efficiency is lower, power utilization is not enough of effectively putting out a fire.

For solving the problems of the technologies described above, the invention provides following technological scheme:

A kind of Pneumatic extinguisher is used spiral case; This Pneumatic extinguisher comprises motor and centrifugal blower; And centrifugal blower comprises impeller 2 and spiral case 3, and the profile line of the inboard profile of said spiral case 3 is the spiral case molded lines, it is characterized in that: said spiral case molded lines comprises the first circular arc line AB, the second circular arc line BC and three-arc line CD successively from snail tongue A; Wherein, The first circular arc line AB is radius angle to the first intersection points B of≤180 ° of rotations around the center of impeller 2 clockwise with R from snail tongue A, and the second circular arc line BC and three-arc line CD are plotted as log spiral by five equilibrium basic circle method not, and wherein the second circular arc line BC is for being R from first intersection points B to the second intersection point C and radius _aCircular arc, its pairing square is the length of side with a, three-arc line CD is for D to the second intersection point C and radius are R from the intake grill summit _bCircular arc, its pairing square is the length of side with b.

The first circular arc line AB from snail tongue A with R be radius clockwise around the center Rotate 180 of spiral case molded lines ° to first intersection points B.

R=107.11mm，a=6.9mm，b=9.9mm，R _a=107.68mm，R _b=124.65mm。

The internal surface of the first circular arc line AB is provided with rubber pad 1.

Compared with prior art, beneficial effect of the present invention is:

Spiral case of the present invention from snail tongue place clockwise≤spiral case molded lines in 180 ° the angle adopts circular arc line; The spiral case molded lines of another part is drawn with inequilateral basic circle method becomes log spiral; The internal surface of first circular arc line is provided with rubber pad simultaneously; Avoid impeller and produce friction with spiral case, reduced the snail tongue room simultaneously, thereby reduce the backflow at snail tongue place because dynamic balance is bad.Under dynamic constant prerequisite; Through improving the design method of Pneumatic extinguisher with the spiral case molded lines; Reduced the eddy current loss of blower fan; Increased the power utilization of motor and effective fire extinguishing wind speed of Pneumatic extinguisher, thereby improved its fire-fighting efficiency, made it can be used for putting out the bigger fire of combustion intensity.

Description of drawings

Fig. 1 is the structural representation of centrifugal blower;

Fig. 2 is the schematic representation of spiral case molded lines.

Reference character

1 rubber pad, 2 impellers

3 spiral case A snail tongues

The B first intersection point C second intersection point

D intake grill summit AB first circular arc line

The BC second circular arc line CD three-arc line

Embodiment

Below in conjunction with instance and accompanying drawing, the present invention is described in further detail.

The disclosed a kind of Pneumatic extinguisher of the present invention is used spiral case, and this Pneumatic extinguisher comprises motor and centrifugal blower, and the structure of this centrifugal blower is as shown in Figure 1, comprises impeller 2 and spiral case 3.

As shown in Figure 2; A kind of Pneumatic extinguisher of the present invention comprises the first circular arc line AB, the second circular arc line BC and three-arc line CD with the spiral case molded lines of spiral case from snail tongue A successively; Wherein, The first circular arc line AB is that radius rotates≤180 ° angle to the first intersection points B clockwise around the center of impeller 2 with R from snail tongue A; The second circular arc line BC and three-arc line CD have formed the log spiral of drawing by five equilibrium basic circle method not, and wherein second circular arc line (BC) is for being R from first intersection point (B) to second intersection point (C) and radius _aCircular arc, its pairing square is the length of side with a, three-arc line (CD) for from the intake grill summit (D) to second intersection point (C) and radius be R _bCircular arc, its pairing square is the length of side with b.

Wherein, the second circular arc line BC and three-arc line CD are plotted as log spiral by five equilibrium basic circle method not, at first by the log spiral equation

Wherein, R is the radius of the circular arc of forming log spiral, and R2 is an impeller radius, and B is the spiral case width, the circumferential speed of c ' 2u after for the outlet of leaf road, and e is the truth of a matter of natural logarithm, Q is the fan design volume flow,

For radius is the cross section of R and the angle between the initial cross section of spiral case, will Bring formula into, obtain R _π, R _{3/2 π}, R _{2 π}, bring into then: $a=\frac{{\mathrm{<figure-callout\; id="3"\; label="R"\; filenames="HDA00001892130500011.png"\; state="\{\{state\}\}">R</figure-callout>}}_{3\mathrm{\&pi;}/2}-R_{\mathrm{\&pi;}}}{2},$ $R_a=\sqrt{\frac{{\mathrm{<figure-callout\; id="3"\; label="R"\; filenames="HDA00001892130500011.png"\; state="\{\{state\}\}">R</figure-callout>}}_{3\mathrm{\&pi;}/2}^2+R_{\mathrm{\&pi;}}^2}{2}};$ $b=\frac{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HDA00001892130500011.png"\; state="\{\{state\}\}">R</figure-callout>}}_{2\mathrm{\&pi;}}-{\mathrm{<figure-callout\; id="3"\; label="R"\; filenames="HDA00001892130500011.png"\; state="\{\{state\}\}">R</figure-callout>}}_{3/2\mathrm{\&pi;}}}{2};$ $R_a=\sqrt{\frac{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HDA00001892130500011.png"\; state="\{\{state\}\}">R</figure-callout>}}_{2\mathrm{\&pi;}}^2+{\mathrm{<figure-callout\; id="3"\; label="R"\; filenames="HDA00001892130500011.png"\; state="\{\{state\}\}">R</figure-callout>}}_{3\mathrm{\&pi;}/2}^2}{2}},$ Can try to achieve a, b, R _a, R _b

Preferably, the first circular arc line AB from snail tongue A with R be radius clockwise around the center Rotate 180 of spiral case molded lines ° to first intersection points B.

Preferably, R=107.11mm, thus try to achieve a=6.9mm, b=9.9mm, R _a=107.68mm, R _b=124.65mm.

Be to improve the power utilization of motor, the spiral case molded lines in the comparatively serious zone of eddy current is the scope that rises clockwise≤180 ° of snail tongue adopts the first circular arc line AB, reduces this regional air inflow, thus the eddy current loss of minimizing blower fan; The second circular arc line BC and three-arc line CD adopt inequilateral basic circle method to be plotted as log spiral, have increased the airspeed of blower fan outlet.And, consider the dynamic balance of impeller, the internal surface of the first circular arc line AB is provided with rubber pad 1, when avoiding the impeller high speed rotating and spiral case produce friction, reduced the snail tongue room of blower fan simultaneously, thereby reduced the backflow at snail tongue place, improve the wind speed of blower fan.

Claims (4)

1. a Pneumatic extinguisher is used spiral case; This Pneumatic extinguisher comprises motor and centrifugal blower; And centrifugal blower comprises impeller (2) and spiral case (3); The profile line of the inboard profile of said spiral case (3) is the spiral case molded lines; It is characterized in that: said spiral case molded lines comprises first circular arc line (AB), second circular arc line (BC) and three-arc line (CD) successively from snail tongue (A), and wherein, first circular arc line (AB) is that radius rotates≤180 ° angle to the first intersection point (B) clockwise around the center of impeller (2) with R from snail tongue (A); Second circular arc line (BC) and three-arc line (CD) are plotted as log spiral by five equilibrium basic circle method not, and wherein second circular arc line (BC) is for being R from first intersection point (B) to second intersection point (C) and radius _aCircular arc, its pairing square is the length of side with a, three-arc line (CD) for from the intake grill summit (D) to second intersection point (C) and radius be R _bCircular arc, its pairing square is the length of side with b.

2. use spiral case like claims 1 described Pneumatic extinguisher, it is characterized in that: first circular arc line (AB) from snail tongue (A) with R be radius clockwise around the center Rotate 180 of spiral case molded lines ° to first intersection point (B).

3. use spiral case like claims 1 described Pneumatic extinguisher, it is characterized in that: R=107.11mm, a=6.9mm, b=9.9mm, R _a=107.68mm, R _b=124.65mm.

4. use spiral case like claims 1 described Pneumatic extinguisher, it is characterized in that: the internal surface of first circular arc line (AB) is provided with rubber pad (1).

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