CN112762011A

CN112762011A - Explosion-proof centrifugal ventilator and explosion-proof method thereof

Info

Publication number: CN112762011A
Application number: CN201911077887.3A
Authority: CN
Inventors: 李娜; 宫中昊; 于辉; 程龙军; 单晓雯; 尹树孟
Original assignee: China Petroleum and Chemical Corp; Sinopec Qingdao Safety Engineering Institute
Current assignee: China Petroleum and Chemical Corp; Sinopec Qingdao Safety Engineering Institute
Priority date: 2019-11-06
Filing date: 2019-11-06
Publication date: 2021-05-07

Abstract

The invention discloses an explosion-proof centrifugal ventilator which comprises an impeller, a casing, a transmission assembly and an explosion-proof motor, wherein the transmission assembly comprises a main shaft, a bearing and a coupler. The explosion-proof centrifugal ventilator further comprises a first fire-retardant component and a second fire-retardant component which are respectively arranged at the air inlet and the air outlet of the casing. The invention also discloses an explosion-proof method of the explosion-proof centrifugal ventilator, which comprises the following steps: a first fire retardant component and a second fire retardant component are respectively arranged at the air inlet and the air outlet of the shell; monitoring combustion of the first and second flame retardant assemblies; when the burning time of the first fire retardant component or the second fire retardant component reaches 45-55% of the corresponding safe burning time, an alarm signal is sent out, and the air supply of the explosion-proof centrifugal ventilator is closed. According to the invention, the fire-retardant component is arranged to block flame propagation, so that the safety risk caused by burning and explosion of the centrifugal ventilator in an explosive environment is reduced.

Description

Explosion-proof centrifugal ventilator and explosion-proof method thereof

Technical Field

The invention relates to the field of gas conveying equipment, in particular to an explosion-proof centrifugal ventilator and an explosion-proof method thereof.

Background

In the VOCs treatment engineering, the collection and transportation of waste gas are the treatment source of the engineering, and the safe and stable operation of the whole system is closely related to the correct and safe collection mode. Because the medium transported in the device is a mixture of oil gas and air, the mixed gas is within the explosion limit range and belongs to flammable and explosive potential explosive gas environments, and such potential explosive environments with long-term continuous existence are defined as the highest-grade 0-zone dangerous places.

The inside effective spark that produces of centrifugal fan as mist gets into 0 district air-extracting equipment of explosion before the oil gas recovery device, if the ventilation blower is inside, not only can arouse the inside explosion of fan after being lighted, more can spread to the outside, leads to rear end oil gas recovery device to catch fire and explode on the one hand, and on the other hand causes the pipeline in intercommunication jar district to take place the tempering, incurs bigger danger. Therefore, once the ventilator is ignited for explosion, inestimable loss is brought, so that the fireproof and explosion-proof characteristics of the ventilator are ensured, and the research and development of the integral explosion-proof fan equipment for treating the VOCs are ensured, so that the important significance is brought to the equipment safety and the personal safety.

Explosion-proof ventilation blower only concerns the motor explosion-proof among the prior art, takes place the safeguard measure after dangerous to the fan body and considers inadequately, needs research and development and the manufacturing of whole explosion-proof ventilation blower under this operating mode urgently.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

One of the objectives of the present invention is to provide an explosion-proof centrifugal fan and an explosion-proof method thereof, so as to improve the safety of the existing explosion-proof centrifugal fan in the potentially explosive environment.

To achieve the above object, according to a first aspect of the present invention, there is provided an explosion-proof centrifugal ventilator comprising an impeller, a casing, a transmission assembly and an explosion-proof motor, the transmission assembly comprising a main shaft, a bearing and a coupling. The explosion-proof centrifugal ventilator further comprises a first fire-retardant component and a second fire-retardant component which are respectively arranged at the air inlet and the air outlet of the casing.

Furthermore, in the above technical scheme, the first flame retardant assembly comprises a first flame retardant core and a first flange pair, and one end of the first flange pair is connected with the air inlet of the casing; the second back-fire relief subassembly includes that second back-fire relief core and second flange are right, and the one end of second flange is connected with the air outlet of casing.

Furthermore, in the above technical scheme, the other ends of the first flange pair and the second flange pair are respectively connected with the corrugated pipe.

Further, among the above-mentioned technical scheme, first back-fire relief core and second back-fire relief core are equipped with temperature sensor.

Further, in the above technical solution, the temperature sensor is a platinum rhodium thermocouple or a palladium rhodium thermocouple.

Further, in the above technical scheme, the maximum explosion pressure that the casing can bear is 0.8-1.2 MPa.

Further, in the above technical scheme, the inner wall of the casing is provided with a lining layer.

Further, in the above technical solution, the lining layer is made of copper, stainless steel or polytetrafluoroethylene.

Further, in the above technical scheme, the lining is fixed on the inner wall of the casing by welding or riveting.

Further, in the above technical scheme, the main shaft is provided with a labyrinth dry gas seal.

According to a second aspect of the present invention, there is provided an explosion-proof method of an explosion-proof centrifugal ventilator comprising an impeller, a casing, a transmission assembly and an explosion-proof motor, the transmission assembly comprising a main shaft, a bearing and a coupling, the explosion-proof method comprising: a first fire retardant component and a second fire retardant component are respectively arranged at the air inlet and the air outlet of the shell; monitoring combustion of the first and second flame retardant assemblies; when the burning time of the first fire retardant component or the second fire retardant component reaches 45-55% of the corresponding safe burning time, an alarm signal is sent out, and the air supply of the explosion-proof centrifugal ventilator is closed.

Further, among the above-mentioned technical scheme, through the burning of first back-fire relief subassembly and second back-fire relief subassembly of temperature sensor monitoring.

Further, in the above technical scheme, the safe combustion time is longer than the emergency shutdown reaction time of the explosion-proof centrifugal ventilator.

Further, in the above technical scheme, a lining layer is arranged on the inner wall of the shell.

Further, in the above technical scheme, the thickness of the lining layer of the casing is set according to the material of the lining layer and the power of the explosion-proof motor.

Compared with the prior art, the invention has the following beneficial effects:

1. through setting up back-fire relief subassembly, block flame propagation to reduce the safety risk that centrifugal fan blasting brought under the explosive environment.

2. The stable combustion in the fire retardant component is monitored, and linkage alarm is set to avoid the fire from spreading to the other side of the fire retardant component to cause major accidents.

3. Through the protection such as the lining that sets up the casing, can avoid enlarging danger when centrifugal fan accident appears.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood and to make the technical means implementable in accordance with the contents of the description, and to make the above and other objects, technical features, and advantages of the present invention more comprehensible, one or more preferred embodiments are described below in detail with reference to the accompanying drawings.

Drawings

Fig. 1 is a schematic structural view of an explosion-proof centrifugal ventilator according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a firestop core according to an embodiment of the present invention.

Description of the main reference numerals:

10-an explosion-proof motor, 21-an impeller, 22-a machine shell, 221-an air inlet, 222-an air outlet, 31-a main shaft, 33-a coupler, 41-a base, 42-a bearing seat, 50-a first fire retardant component, 51-a first fire retardant core, 521, 522-a first flange pair and 70-a temperature sensor.

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.

Spatially relative terms, such as "below," "lower," "upper," "above," "upper," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the object in use or operation in addition to the orientation depicted in the figures. For example, if the items in the figures are turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the elements or features. Thus, the exemplary term "below" can encompass both an orientation of below and above. The article may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative terms used herein should be interpreted accordingly.

In this document, the terms "first", "second", etc. are used to distinguish two different elements or portions, and are not used to define a particular position or relative relationship. In other words, the terms "first," "second," and the like may also be interchanged with one another in some embodiments.

The centrifugal ventilator is used as an air extraction device at the inlet of an organic gas recovery and treatment device, a medium conveyed in the device is a mixture of oil gas and air, and a mixed gas is in an explosion limit range and belongs to a flammable and explosive potential explosive gas environment. The invention optimizes the structure of the ventilator by adopting the explosion-proof protection element for blocking flame propagation and the explosion-proof shell, realizes the integral explosion prevention of the ventilator, and thus reduces the safety risk caused by the explosion of the ventilator in an explosive environment.

As shown in fig. 1, an explosion-proof centrifugal ventilator according to an embodiment of the present invention includes an explosion-proof motor 10, a through-flow assembly, and a transmission assembly. The through-flow assembly comprises an impeller 21 and a casing 22, wherein the casing 22 is provided with an air inlet 221 and an air outlet 222; the transmission assembly comprises a main shaft 31, bearings and a coupling 33. The explosion-proof centrifugal ventilator may further comprise a support assembly comprising a bearing housing 42 and a base 41. When the centrifugal ventilator works, the impeller rotates at a high speed, gas is sucked into the impeller through the air inlet 221 along the axial direction, is bent by 90 degrees in the impeller, flows through the blade channel and is discharged out of the impeller, and finally the gas thrown out by the impeller is concentrated and guided through the shell and is discharged from the air outlet 222. The gas gains energy, pressure is increased, and kinetic energy is increased. It should be understood that the explosion-proof centrifugal ventilator of the present invention does not change the conventional fan structure, and the above-mentioned specific structure is merely exemplary for clearly illustrating the spirit of the present invention, and the present invention is not limited thereto.

Further, in one or more exemplary embodiments of the present invention, the air inlet 221 and the air outlet 222 of the explosion-proof centrifugal fan are provided with a first flame retardant assembly 50 and a second flame retardant assembly (not shown), respectively. The first flame retardant assembly 50 includes a first flame retardant core 51 and a first pair of

flanges

521, 522, the first flame retardant core 51 is disposed between the first pair of

flanges

521, 522, and one end of the first pair of

flanges

521, 522 is connected to the air inlet 221 of the cabinet 22. Illustratively, the other end of the first pair of

flanges

521, 522 may be connected to a bellows (not shown), it being understood that the invention is not limited thereto. The structure and connection of the second firestop assembly is the same as the first firestop assembly and will not be described further.

Further, as shown in FIG. 2, in one or more exemplary embodiments of the invention, first fire barrier core 51 is comprised of a solid element having a plurality of interstitial, narrow passages through which gas can pass. The material of the fire retardant core can be 316 stainless steel, 316L stainless steel or Hastelloy. The material rigidity of the fire retardant core can bear corresponding mechanical and thermal impact, flame is extinguished through heat loss of the plurality of channels, violent flame after deflagration in the fan is prevented, and flowing resistance is small. The diameter of the fire retardant core is twice that of the pipeline, and the fire retardant component has the characteristics of large volume and heavy weight generally. In addition, because the fire retardant assembly is modularly integrated, the installation manner is also optimized.

Further, because the pressure drop generated by installing the fire retardant component affects the working efficiency of the centrifugal fan, the pressure loss of the fire retardant component becomes an important parameter index, and the problem that the flow is insufficient if the medium flow in the pipeline is enough to supply the centrifugal fan is solved. The reasons for the pressure drop are the structural form of the firestop element and the composition and flow rate of the gaseous medium. The single-side pressure drop is generally less than 5bar in VOCs treatment, and the load pressure can be solved by increasing the power of the motor due to the fact that the pressure drop increases the load of the centrifugal ventilator. In addition, explosion-proof machine 10 requires to use 5 ~ 50Hz frequency conversion, and this is decided by VOCs treatment device, and when there is not oil gas inlet pressure, explosion-proof machine 10 still need keep 10Hz operation, prevents that centrifugal fan from shutting down. The benefit of installation back-fire relief subassembly is that if combustible gas is ignited by the inside electric spark of ventilation blower or mechanical spark, flame will become a plurality of tiny flames behind the tiny passageway of many that the back-fire relief core, when flame is cut apart to a certain extent, the heat of transferring away through the passageway is enough to fall the temperature below the combustible ignition point to enable flame or spark not pass back-fire relief core and be stopped or extinguish, can prevent that gas flame from spreading to whole pipe network, also can prevent to take place the backfire accident on the pipeline. Although such a flame retardant core can withstand high temperature and high pressure generated by deflagration, it cannot prevent stable combustion and detonation for a long time. Thus, in one or more embodiments of the invention, the explosion-proof centrifugal ventilator is provided with an intelligent monitoring system, for example, a temperature sensor 70 may be provided on the flame-retardant core. The temperature sensor 70 monitors the flame combustion condition by detecting a temperature signal to determine whether stable combustion of the flame occurs. The flame retardant core may burn until it is unable to prevent the fire from spreading to the other side. Under this condition, the temperature that detects through temperature sensor 70 can monitor the burning of back-fire relief subassembly, and when the burning time of back-fire relief subassembly reached 45 ~ 55% of its safe burning time, send alarm signal and close explosion-proof centrifugal fan's air feed. Illustratively, the temperature sensor 70 is preferably a platinum rhodium thermocouple or a palladium rhodium thermocouple.

Further, in one or more exemplary embodiments of the present invention, the housing 22 of the explosion-proof centrifugal ventilator is of a rigid design. Even the weakest part of the housing 22 is subjected to a maximum explosion pressure of 0.8 to 1.2MPa in the impact test, the deformation is extremely small to ensure that the rotating parts do not contact the housing 22. The casing distortion caused by the fact that a pipeline system is connected and lacks a flexible joint and damages an inlet sleeve and an outlet sleeve in the installation stage is avoided, or when an inlet of the centrifugal ventilator is closed, the casing distortion deformation caused by the fact that the air pressure in the pipeline system is lower than the atmospheric pressure is avoided, and the rotating part and the casing are in contact friction.

Further, in one or more exemplary embodiments of the present invention, the internal space of the explosion-proof centrifugal ventilator is sealed, and a lining layer (not shown) is disposed on the inner wall of the casing 22, so that the risk that the heat accumulation in the casing is difficult to rapidly lead the energy out to cause the casing to burst can be reduced. Illustratively, the material of the underlayer may be selected from metals, such as copper, stainless steel, etc., and may also be selected from non-metals, such as polytetrafluoroethylene, etc. The minimum thickness of the lining layer is shown in the following table, and the thickness of the lining layer is related to the material of the lining layer and the driving power of the explosion-proof motor. The lining should be firmly fixed to the inner wall of the casing, for example by welding, riveting or hardening with a compatible material, while also taking care that no galvanic reaction occurs between the lining and the base material of the casing.

Further, in one or more exemplary embodiments of the present invention, the main shaft 31 is provided with a sealing member (not shown in the drawings). Preferably, but not limitatively, the sealing element of the main shaft 31 employs a dry gas seal. The sealing element of the spindle is able to prevent the ingress of unwanted particles or objects that may cause internal ignition. Illustratively, the bottom of the casing 22 is provided with a switchable diversion opening 223, which can check the gap between the impeller 21 and the casing 22 and clean deposited impurities.

In one or more embodiments of the present invention, a method of explosion protection of an explosion-proof centrifugal ventilator comprises: a first fire retardant component and a second fire retardant component are respectively arranged at the air inlet and the air outlet of the shell; monitoring combustion of the first and second flame retardant assemblies; when the burning time of the first fire retardant component or the second fire retardant component reaches 45-55% of the corresponding safe burning time, an alarm signal is sent out, and the air supply of the explosion-proof centrifugal ventilator is closed.

Further, in one or more exemplary embodiments of the invention, the combustion of the first flame retardant assembly and the second flame retardant assembly is monitored by a temperature sensor.

Further, in one or more exemplary embodiments of the present invention, the safe combustion time is greater than the emergency shutdown reaction time of the explosion-proof centrifugal ventilator.

Further, in one or more exemplary embodiments of the present invention, a lining layer is provided on an inner wall of the housing.

Further, in one or more exemplary embodiments of the present invention, the thickness of the lining of the cabinet is set according to the material of the lining and the power of the explosion-proof motor.

The present invention will be described in more detail by way of specific examples, which should be construed as being illustrative only and not limiting.

Example 1

Referring to fig. 1, the housing 22 of the explosion-proof centrifugal fan of the present embodiment is made of 304 stainless steel and can withstand an impact pressure of 1.0MPa through an impact test. The thickness of the fire barrier core of the first fire barrier assembly was 170mm, the diameter 69mm and the weight of the first fire barrier assembly was 10 kg. The thickness of the fire barrier core of the second fire barrier assembly was 170mm, the diameter 69mm and the weight of the second fire barrier assembly 10 kg.

Fire-retardant subassembly has been installed to explosion-proof centrifugal fan's of this embodiment air intake and air outlet, can prevent effectively that the ventilation blower from taking place the detonation after, stretching of flame. In addition, the firestop assembly of this example has a weight reduction of about 50% due to the absence of a conventional housing.

Example 2

In this embodiment, on the basis of the structure of embodiment 1, the inner wall of the casing 22 is provided with a lining layer, the lining layer is made of teflon, and the thickness of the lining layer is 2 mm.

This embodiment compares in embodiment 1, has further promoted the protection of casing, avoids the ventilation blower to take place to explode and causes bigger danger.

Example 3

This example is based on the structure of example 1, with temperature sensors in the first and second flame retardant assemblies. When the temperature detected by the temperature sensor reaches 60K, the fire-retardant component is considered to be burning, the safe burning time of the fire-retardant component is 30min, and when the burning time of the fire-retardant component reaches 50% of the safe burning time, an audible and visual alarm signal is sent out and the air supply of the explosion-proof centrifugal ventilator is locked and closed.

Compared with the embodiment 1, the fire alarm device has the advantages that the fire interlocking alarm is additionally arranged so as to prevent fire from spreading to the other side of the fire retardant component and causing major accidents.

Example 4

In this embodiment, on the basis of the structure of embodiment 1, the inner wall of the casing 22 is provided with a lining layer, the lining layer is made of teflon, and the thickness of the lining layer is 2 mm. Temperature sensors are provided in the first and second flame retardant assemblies. When the temperature rise detected by the temperature sensor reaches 20K, the fire-retardant component is considered to be burning, the safe burning time of the fire-retardant component is 2h, and when the burning time of the fire-retardant component reaches 50% of the safe burning time, an audible and visual alarm signal is sent out and the air supply of the explosion-proof centrifugal ventilator is locked and closed.

Compared with the embodiment 1, the protection of the casing is further improved, and the greater danger caused by the explosion of the ventilator is avoided; and a combustion interlocking alarm is additionally arranged to prevent fire from spreading to the other side of the fire retardant component to cause major accidents.

Example 5

Referring to fig. 1, the housing 22 of the explosion-proof centrifugal fan of the present embodiment is made of 304 stainless steel and can withstand an impact pressure of 1.0MPa through an impact test. The thickness of the fire barrier core of the first fire barrier assembly was 150mm, the diameter was 117mm and the weight of the first fire barrier assembly was 15.5 kg. The thickness of the fire barrier core of the second fire barrier assembly was 150mm, the diameter was 117mm and the weight of the second fire barrier assembly was 15.5 kg.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. Any simple modifications, equivalent changes and modifications made to the above exemplary embodiments shall fall within the scope of the present invention.

Claims

1. The utility model provides an explosion-proof centrifugal fan, its includes impeller, casing, drive assembly and explosion-proof motor, drive assembly includes main shaft, bearing and shaft coupling, its characterized in that, this explosion-proof centrifugal fan still including setting up respectively the air intake of casing and the first back-fire relief subassembly and the second back-fire relief subassembly of air outlet.

2. The explosion-proof centrifugal ventilator of claim 1 wherein the first flame retardant assembly comprises a first flame retardant core and a first pair of flanges, one end of the first pair of flanges being connected to the air inlet of the housing; the second back-fire relief assembly comprises a second back-fire relief core and a second flange pair, and one end of the second flange pair is connected with the air outlet of the machine shell.

3. An explosion-proof centrifugal ventilator according to claim 2 wherein the other ends of the first and second flange pairs are respectively connected to a bellows.

4. An explosion-proof centrifugal ventilator as claimed in claim 2 in which the first and second flame-retardant cores are provided with temperature sensors.

5. An explosion-proof centrifugal ventilator according to claim 4 in which the temperature sensor is a platinum rhodium thermocouple or a palladium rhodium thermocouple.

6. The explosion-proof centrifugal ventilator of claim 1 wherein the maximum explosion pressure that the enclosure can withstand is 0.8-1.2 MPa.

7. An explosion proof centrifugal ventilator according to claim 1 wherein the inner wall of the housing is lined.

8. An explosion proof centrifugal ventilator according to claim 7 wherein the lining is made of copper, stainless steel or polytetrafluoroethylene.

9. An explosion proof centrifugal ventilator according to claim 7 wherein the lining is fixed to the inner wall of the casing by welding or riveting.

10. An explosion proof centrifugal ventilator according to claim 1 wherein the main shaft is provided with a labyrinth dry gas seal.

11. An explosion-proof method of an explosion-proof centrifugal fan, the explosion-proof centrifugal fan comprises an impeller, a casing, a transmission assembly and an explosion-proof motor, the transmission assembly comprises a main shaft, a bearing and a coupling, and the explosion-proof method is characterized by comprising the following steps:

a first fire retardant component and a second fire retardant component are respectively arranged at the air inlet and the air outlet of the shell;

monitoring combustion of the first flame retardant assembly and the second flame retardant assembly;

and when the burning time of the first fire retardant component or the second fire retardant component reaches 45-55% of the corresponding safe burning time, sending an alarm signal and closing the air supply of the explosion-proof centrifugal ventilator.

12. An explosion proof centrifugal ventilator explosion proof method according to claim 11 wherein the combustion of the first and second fire retardant assemblies is monitored by a temperature sensor.

13. An explosion protection method for an explosion protection centrifugal fan according to claim 11, wherein the safe combustion time is greater than an emergency shutdown reaction time of the explosion protection centrifugal fan.

14. An explosion-proof centrifugal ventilator according to claim 11 wherein a lining layer is provided on an inner wall of the casing.

15. An explosion proof method of an explosion proof centrifugal ventilator according to claim 14, wherein the thickness of the lining layer of the casing is set according to the material of the lining layer and the power of the explosion proof motor.