CN111608908A

CN111608908A - Dry-type screw blower

Info

Publication number: CN111608908A
Application number: CN202010598308.6A
Authority: CN
Inventors: 王帅
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-06-28
Filing date: 2020-06-28
Publication date: 2020-09-01

Abstract

The invention discloses a dry-type screw blower which comprises a front cover, a front sealing plate, a casing, an exhaust plate and a rear cover, wherein the front sealing plate is arranged between the front cover and the casing; lubricating oil is filled between the front cover and the front sealing plate and between the rear cover and the exhaust plate partially for lubricating the gear, the positioning bearing and the floating bearing; the composite seals at the front end and the rear end are arranged on the side close to the screw cavity to prevent lubricating oil from flowing into the screw cavity, and the shaft seal is arranged at the shaft extending end of the front cover of the driving screw for sealing. The product has the advantages of simple structure, mature technology, energy conservation, practicality, long service life, bright prospect and considerable profit.

Description

Dry-type screw blower

Technical Field

The invention relates to a novel screw air blower, belongs to the field of compressible fluid machinery, and is particularly suitable for occasions where a high-pressure fan with energy-saving requirements is used.

Background

In the manufacturing process of the blower, the traditional Roots blower is not internally compressed and has high energy consumption, and the traditional screw blower has a leakage triangle, so that the leakage amount of the blower is increased along with the increase of the pressure. On one hand, the flow rate is reduced rapidly along with the increase of the pressure at the same rotating speed, and the highest pressure which can be reached is low; on the other hand, the traditional screw blower is complex in processing equipment, a processing machine tool is generally imported from abroad, the cost is high, and the processing area is large.

Disclosure of Invention

Based on the defects of the prior art, the invention provides the dry screw blower with low energy consumption, high pressure, easy processing and low cost.

The technical scheme of the dry screw blower comprises the following steps:

a dry screw blower comprises a front cover (1), a front sealing plate (2), a casing (3), an exhaust plate (4) and a rear cover (5), wherein the front sealing plate (2) is arranged between the front cover (1) and the casing (3) for separation, the exhaust plate (4) is arranged between the casing (3) and the rear cover (5) for separation, a driving screw (6) and a driven screw (7) are arranged in a screw cavity inside the casing (3), one ends of the driving screw (6) and the driven screw (7) are connected through a gear (11), one ends of the driving screw (6) and the driven screw (7) close to the rear cover (5) are fixed through a positioning bearing (8), and one ends of the driving screw (6) and the driven screw (7) close to the front cover (1) are fixed through a floating bearing (9);

the front end and the rear end of the composite seal (10) are respectively arranged between the front cover (1) and the screw cavity and between the rear cover (5) and the screw cavity, the positioning bearing (8) and the rear end of the composite seal (10) are arranged in the exhaust plate (4), the exhaust plate (4) is provided with an exhaust port, and the floating bearing (9) and the front end of the composite seal (10) are arranged in the front sealing plate (2); partial lubricating coolants are filled between the front cover (1) and the front sealing plate (2) and between the rear cover (5) and the exhaust plate (4) and are used for lubricating the gear (11), the positioning bearing (8) and the floating bearing (9); the composite seals (10) at the front end and the rear end are arranged at the side close to the screw cavity to prevent the lubricating agent from flowing into the screw cavity, and the driving screw (6) is sealed by a shaft seal (12) at the shaft extending end of the front cover (1).

Furthermore, bolts are fixedly connected between the front cover (1) and the front sealing plate (2), between the front sealing plate (2) and the casing (3), between the casing (3) and the exhaust plate (4), and between the exhaust plate (4) and the rear cover (5).

Furthermore, the driving screw rod (6), the driven screw rod (7) and the positioning bearing (8) are fixed by locking nuts.

Furthermore, when the driving screw (6) and the driven screw (7) expand when heated, the floating bearings (9) expand to one side, and the floating bearings (9) allow the screws to axially move for a certain distance because the inner rings of the bearings are movable.

Furthermore, the gear (11), the driving screw (6) and the driven screw (7) are pressed tightly by locking nuts, and do not move relatively.

Further, the air inlet of the dry type screw air blower is arranged on the shell and far away from the exhaust plate, so that air flow between the air inlet and the exhaust port can fully penetrate through the driving screw (6) and the driven screw (7), and the exhaust port is arranged on the side face of the exhaust plate (4) and conducts high-pressure air to the outside.

Further, the shaft extending ends of the gear (11) and the driving screw (6) are arranged on two sides of the machine shell (3) or on the same side of the machine shell (3).

Further, when the gear (11) and the shaft extending end of the driving screw (6) are arranged at the two sides of the machine shell (3), the gear (11) and the positioning bearing (8) use lubricating oil as a lubricating coolant, and the floating bearing (9) uses lubricating oil or lubricating grease as a lubricating coolant; when the gear (11) and the shaft extending end of the driving screw (6) are arranged on the same side of the machine shell (3), the positioning bearing (8), the gear (11) and the floating bearing (9) only can use lubricating oil as lubricating and cooling agents.

The invention has the following technical effects:

compared with the Roots blower which has no internal compression and high energy consumption, the novel dry-type screw blower has the advantages that the internal compression is realized, the energy consumption is reduced, the strict sealing brought by the conjugate curve of the end face of the screw is realized, the flow change along with the pressure at the same rotating speed is small, the processing is easy, and the processing cost is reduced.

The traditional screw air blower has a leakage triangle, so that the leakage amount of the air blower is increased along with the increase of pressure, the flow rate is reduced rapidly along with the increase of the pressure at the same rotating speed, and the highest pressure which can be reached is low; and the traditional screw air blower has the defects of complex processing equipment and large processing area, and the product has the advantages of simple structure, mature technology, strong innovation, obvious substitution effect, energy conservation, practicality, long service life, bright prospect and considerable profit. Meanwhile, the screw machining of the invention can be replaced by domestic machine tool machining due to simple structure, and the manufacturing cost is greatly reduced.

Drawings

FIG. 1 is a block diagram of the present invention;

FIG. 2 is a top view of an air inlet in the enclosure;

FIG. 3 is a view of the exhaust port on the exhaust plate;

FIG. 4 is a profile view of a single screw end face;

FIG. 5 is a twin screw end profile view;

fig. 6 is a schematic diagram of four different working states of the twin-screw.

In the figure: 1. a front cover; 2. a front sealing plate; 3. a housing; 4. an exhaust plate; 5. a rear cover; 6. a driving screw; 7. a driven screw; 8. positioning the bearing; 9. a floating bearing; 10. performing composite sealing; 11. a gear; 12. shaft sealing;

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

As shown in fig. 1, the dry screw blower of the present invention includes a front cover 1, a front sealing plate 2, a casing 3, an exhaust plate 4, and a rear cover 5, wherein the front sealing plate 2 is arranged between the front cover 1 and the casing 3 for separation, the exhaust plate 4 is arranged between the casing 3 and the rear cover 5 for separation, a screw cavity inside the casing 3 is provided with a driving screw 6 and a driven screw 7, one ends of the driving screw 6 and the driven screw 7 are connected through a gear 11, one ends of the driving screw 6 and the driven screw 7 close to the rear cover 5 are fixed through a positioning bearing 8, and one ends of the driving screw 6 and the driven screw 7 close to the front cover 1 are fixed through a floating bearing 9;

the front end and the rear end of the composite seal 10 are respectively arranged between the front cover 1 and the screw cavity and between the rear cover 5 and the screw cavity, the positioning bearing 8 and the rear end of the composite seal 10 are arranged in the exhaust plate 4, the exhaust plate 4 is provided with an exhaust port, and the floating bearing 9 and the front end of the composite seal 10 are arranged in the front sealing plate 2; partial lubricating coolants are filled between the front cover 1 and the front sealing plate 2 and between the rear cover 5 and the exhaust plate 4 and are used for lubricating the gear 11, the positioning bearing 8 and the floating bearing 9; the composite seals 10 at the front and rear ends are disposed on the side adjacent to the screw cavity to prevent the flow of lubricant into the screw cavity, and the drive screw 6 is sealed by a shaft seal 12 at the shaft-extending end of the front cover 1.

The front cover 1 and the front sealing plate 2, the front sealing plate 2 and the casing 3, the casing 3 and the exhaust plate 4, and the exhaust plate 4 and the rear cover 5 are all fixedly connected by bolts.

The driving screw 6, the driven screw 7 and the positioning bearing 8 are fixed by locking nuts.

When the driving screw 6 and the driven screw 7 expand due to heating, the floating bearings 9 expand towards one side, and the floating bearings 9 allow the screws to axially move for a certain distance because the inner rings of the bearings are movable.

The gear 11, the driving screw 6 and the driven screw 7 are pressed by locking nuts and do not move relatively.

As shown in fig. 2 to 3, the air inlet of the dry screw blower is provided on the side of the casing 3 remote from the exhaust plate, and the air inlet and the exhaust port are spatially upward and laterally outward.

The gear 11 and the shaft extending end of the driving screw 6 are disposed on both sides of the housing 3, or disposed on the same side of the housing 3.

As an embodiment of the present invention, when the gear 11 and the shaft-protruding end of the driving screw 6 are disposed at both sides of the housing 3, the gear 11 and the bearing between the rear cover 5 and the exhaust plate 4 must be lubricated with lubricating oil, and the bearing on the front sealing plate 2 may be lubricated with either lubricating oil or grease. When the gear 11 and the shaft-projecting end of the drive screw 6 are arranged on the same side of the housing 3, the positioning bearing 8, the gear 11 and the floating bearing 9 can only be lubricated with lubricating oil.

The front cover is connected with the front sealing plate, the front sealing plate is connected with the machine shell, the machine shell is connected with the exhaust plate, and the exhaust plate is connected with the rear cover through bolts. The screw rod and the 8 positioning bearing are fixed by a locking nut. When the screw rod expands under heat, the screw rod expands towards one side of the floating bearing. The floating bearing allows the screw rod to axially move for a certain distance because the inner ring of the bearing is movable. The 11 gear and the screw rod are pressed by a locking nut and do not move relatively. The front cover and the rear cover are filled with partial lubricating oil for lubricating the gear and the bearing. And 10 composite seals are arranged between the front cover, the rear cover and the screw cavity, and the composite seals prevent lubricating oil from flowing into the screw cavity, so that the complete oil-free suction and exhaust process is ensured. The driving screw rod is sealed by a shaft seal at the extending section of the front cover.

The air inlet of the novel screw blower is arranged on one side of the casing far away from the exhaust plate as shown in figure 2. The shape of the exhaust port in the exhaust plate is shown in fig. 3. The air inlet is arranged on the shell and far away from the exhaust plate, and the exhaust port is arranged on the side surface of the exhaust plate 4 and conducts high-pressure gas to the outside.

The molded line of the screw end surface of the novel screw blower is shown in figure 4 and is formed by the common enclosure of cycloid curves, involute curves and arc curves. The end view spirals two times around the screw axis to form a screw blower screw.

As shown in figures 4-5, in the double-screw structure of the invention, the molded line of the end surface of the screw is sequentially surrounded by a short cycloid curve, an involute curve, an outer arc curve, a long cycloid curve and an inner arc curve, and the screw is spirally wound around the axis of the screw for two circles to form a complete screw. During the design process, the radii of the inner and outer arcs are first determined. First, drawing an inner arc, an outer arc and a cycloid. The cycloid expands diametrically from an inner arc radius to an outer arc radius, angularly from an angle back to the starting angle. Then, an element is determined to draw an involute, and a cycloid is drawn to be tangent with the element, and the redundant part is subtracted. And a line formed by splicing the two curves is moved to the opposite side of the original cycloid (the angles of the two circular arcs are exactly equally divided), and then the redundant circular arcs are cut off to form a surrounded end face curve.

The cycloid equations of the driving screw 6 and the driven screw 7 are as follows:

x (radius of outer arc curve + radius of inner arc curve) sint-radius of outer arc curve sin2t

y ═ c (radius of outer arc curve + radius of inner arc curve) × (st) -radius of outer arc curve × cos2 t;

the radius of the outer circular arc curve is also the outer circular radius in fig. 5; the radius of the inner circular arc curve is also the inner circle radius.

The involute equation is:

x ═ involute base circle radius (cost + t · sint);

y is the base radius of the involute (sint-t cost).

The base radius is a given value. It is smaller than the inner circle radius. The size of the involute expansion angle determines the size of the involute expansion angle, and the angle of the arc is determined.

In the invention, the cycloid is returned to the original angle from one angle, and the starting point has no problem of angle difference. The involute flare angle is determined by the cell radius. The larger the angle of the involute is, the smaller the angle of the arc is. The larger the involute angle, the greater the volumetric efficiency, i.e., the faster the same magnitude of blower flow rate. However, the too large angle of the involute causes the contact surface between the screw and the machine shell to be too narrow, and is not suitable for realizing the dynamic balance by a weight-removing method of the screw.

As an embodiment of the invention, in the blower with the diameter of the air inlet of 150mm, the gas flow of 20 cubic meters per minute and the pressure of 0.8 kilogram, the radius of the outer arc curve is 127.5mm, and the radius of the inner arc curve is set to be 40.5mm to meet the strength requirement of the shaft. In the 20 cubic meter per minute blower described above, we have chosen a cell radius of 27 mm.

FIG. 6 is a schematic view of the twin-screw operation.

The working principle and the working process of the device or the system are described in conjunction with the accompanying drawings;

the invention relates to a novel screw air blower, belongs to the field of compressible fluid machinery, and is particularly suitable for occasions where high-pressure fans with energy-saving requirements are used.

Under the drive of the motor and the gear, the driving screw and the driven screw rotate in the same speed and reverse directions in the shell to expand and compress the volume between the screws and the shell, and gas is sucked from the gas inlet and forced to flow from one end of the gas inlet to one end of the gas outlet along the axial direction. And a gap between 0.1 mm and 0.25 mm is formed between the screw and the exhaust plate, when the gas is compressed to reach the exhaust pressure, the gas is communicated with the exhaust port, the gas is extruded out from the exhaust port, and the exhaust process is finished.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A dry screw blower comprises a front cover (1), a front sealing plate (2), a casing (3), an exhaust plate (4) and a rear cover (5), wherein the front sealing plate (2) is arranged between the front cover (1) and the casing (3) for separation, and the exhaust plate (4) is arranged between the casing (3) and the rear cover (5) for separation, and is characterized in that a driving screw (6) and a driven screw (7) are arranged in a screw cavity inside the casing (3), one ends of the driving screw (6) and the driven screw (7) are connected through a gear (11), one ends of the driving screw (6) and the driven screw (7) close to the rear cover (5) are fixed through a positioning bearing (8), and one ends of the driving screw (6) and the driven screw (7) close to the front cover (1) are fixed through a floating bearing (9);

2. A dry screw blower according to claim 1, characterised in that the front cover (1) and the front sealing plate (2), the front sealing plate (2) and the casing (3), the casing (3) and the discharge plate (4), and the discharge plate (4) and the rear cover (5) are all fixedly connected by bolts.

3. A dry screw blower according to claim 1, characterised in that the drive screw (6), the driven screw (7) and the positioning bearing (8) are secured by means of lock nuts.

4. A dry screw blower according to claim 1, wherein the floating bearing (9) is expanded toward the side of the floating bearing (9) when the driving screw (6) and the driven screw (7) are expanded by heat, and the floating bearing (9) allows the screws to axially move for a certain distance because the inner rings of the bearings are movable.

5. A dry screw blower according to claim 1, characterised in that the gear (11) and the drive screw (6) and the driven screw (7) are pressed against each other by means of lock nuts without relative movement between each other.

6. The dry screw blower according to claim 1, further comprising an air inlet provided on the casing at a position away from the discharge plate to ensure sufficient air flow between the air inlet and the air outlet through the driving screw (6) and the driven screw (7), and an air outlet provided on a side of the discharge plate (4) to conduct the high-pressure air to the outside.

7. A dry screw blower according to claim 1, characterised in that the gear (11) and the shaft-protruding end of the drive screw (6) are arranged on both sides of the housing (3) or on the same side of the housing (3).

8. A dry screw blower according to claim 7, characterized in that when the gear (11) and the shaft-projecting end of the drive screw (6) are disposed on both sides of the housing (3), the gear (11) and the positioning bearing (8) are lubricated with a lubricating oil as a lubricating coolant, and the floating bearing (9) is lubricated with a lubricating oil or with a grease as a lubricating coolant; when the gear (11) and the shaft extending end of the driving screw (6) are arranged on the same side of the machine shell (3), the positioning bearing (8), the gear (11) and the floating bearing (9) only can use lubricating oil as lubricating and cooling agents.