CN105201870B - A kind of centrifugal pump of preposition rotational flow type gas-liquid separater - Google Patents

Abstract

The invention provides a centrifugal pump with a pre-swirl type gas-liquid separator, comprising: a swirl cylinder, including a cylinder wall surrounding a cylinder and an end cap closing one end, the other end of the swirl cylinder is open; Pipe, tangentially connected with the cylinder wall of the swirl cylinder near the end cover; suction pipe, installed on the end cover of the swirl cylinder; centrifugal pump, including a volute with an axial inlet and a tangential outlet, The impeller installed in the volute and the drive shaft of the impeller; the axial inlet is connected with the open end of the cyclone; the present invention combines gas-liquid cyclone separation with a centrifugal pump, and realizes gas-liquid separation and fluid flow as a whole Conveying two functions, the gas is separated before entering the impeller area, it is not easy to cause blockage of the pump inlet, and the gas is not easy to be taken away by the impeller, the degassing ability is stronger, and the formation of a low pressure area in the center of the cyclone is also conducive to dissolving in the liquid The separation of gas further improves the effect of gas-liquid separation.

Description

A kind of centrifugal pump of pre-swirl type gas-liquid separator

technical field

The invention relates to the technical field of gas-liquid separation, in particular to a centrifugal pump with a pre-swirl type gas-liquid separator.

Background technique

In the food industry, during the process of squeezing and stirring fruit juice drinks, more air will be mixed, including free air bubbles and dissolved gases in the liquid. In production, it is often necessary to remove these gases in the liquid to prevent the oxidation of the juice and prolong the storage period.

In recent years, scholars at home and abroad have conducted extensive research on gas-liquid separation operations, but most of them focus on the field of oil-gas separation. There are few studies on the mixed fluid of water and air, especially for the air dissolved in water, which is difficult to separate. In the process of oil and gas separation, the column type gas-liquid cyclone separator has a wide range of applications. The cyclone separator realizes the separation of gas-liquid two-phase through the rotating centrifugal action of the fluid.

For example, the Chinese patent literature with the notification number CN101940860A discloses a gas-liquid separator, which is mainly composed of the following components: a drum and a distributor are arranged in the casing, and the drum is connected to the motor through a transmission device; Inlet and liquid outlet, air inlet and gas outlet; one end of the feed liquid inlet leads to the outside of the shell, the other end is connected to the distributor, the packing layer is arranged in the drum, and is fixedly connected to the drum through the isolation net; The lower end of the gas outlet extends into the inside of the separator, and is installed between the packing layer and the material distribution pipe to lead out the separated gas; there is a gas distribution pipe between the casing and the drum, and the air distribution pipe is full of holes. The air inlets are connected; the feed liquid inlet and the gas outlet are arranged on the top of the casing, and the liquid outlet and the air inlet are arranged at the bottom of the casing; the above invention uses the centrifugal force and supergravity generated by high-speed rotation to make the The raw material liquid is in contact with the air that enters in the opposite direction, and the gas and liquid are two phases. Under the action of the centrifugal force from the drum and the external strong pressure gas, the gas conductor in the raw material liquid is separated from the liquid to achieve the purpose of improving the efficiency.

Another example is a Chinese patent document with the authorized announcement number CN 201381813Y disclosing a column-type gas-liquid cyclone separator to reduce cost and weight. It has a column-type separation tube, with a gas-liquid mixture inlet pipe on the upper part of the column-type separation tube, and the gas-liquid mixture inlet pipe enters the column-type separation tube from an inclined tangential inlet, and the gas outlet is located on the upper part of the column-type separation tube, and the liquid The outlet is located at the lower part of the column separation tube. The column-type gas-liquid cyclone separator is a vertical tube with an inclined tangential inlet and gas and liquid outlets. It relies on the centrifugal force of the swirl to realize the separation of gas and liquid. Compared with the traditional gravity separator, It has the advantages of compact structure, light weight, and cost saving. It is a new type of separation device that replaces the traditional volumetric separator.

The above two kinds of gas-liquid separation use the centrifugal force generated by high-speed rotation to separate the gas in the raw material liquid from the liquid. Although it can effectively separate the free gas in the liquid, it is difficult to separate the dissolved gas in the liquid, and a separate fluid delivery is required. The device is connected with the liquid outlet, and the use is relatively complicated.

Contents of the invention

The invention provides a centrifugal pump with a pre-swirl type gas-liquid separator, which simultaneously completes gas-liquid separation and fluid delivery, has a compact structure and high gas-liquid separation efficiency.

A centrifugal pump of a pre-swirl gas-liquid separator, comprising a feed pipe, a swirl cylinder, a suction pipe and a centrifugal pump, the feed pipe is connected tangentially to the wall of the swirl cylinder, and the One end of the swirl cylinder near the feed pipe is connected to the suction pipe, and the other end is connected to the axial inlet of the centrifugal pump.

The centrifugal pump comprises a volute with an axial inlet and a tangential outlet, an impeller mounted in the volute and a drive shaft for the impeller.

When the present invention is in use, the gas-liquid mixed fluid enters the feed pipe from the external pipeline, and enters the swirl cylinder tangentially through the guidance of the feed pipe. The fluid forms a high-speed rotating liquid ring. The trajectory of the line moves to the axial inlet of the centrifugal pump (the movement of the fluid in one direction can be realized by the gravity of the fluid itself, such as a vertical swirl cylinder, or it can be achieved by setting the feed pipe at an angle relative to the axis). The gas in the liquid is separated under the action of centrifugal force.

In order to improve the effect of gas-liquid separation, preferably, the pumping tube is connected to a vacuum pump, and under the joint action of the high-speed liquid swirl and the vacuum pump connected to the pumping tube, a negative pressure is generated in the center of the swirling cylinder, and the solubility of the gas in the liquid is used to As the pressure decreases, the gas dissolved in the liquid is also separated, and the gas is discharged through the exhaust pipe, and the degassed liquid swirls into the volute, and is transported out after being pressurized by the impeller. The swirling fluid can be It quickly enters the volute and is output, and the liquid delivery efficiency is greatly improved.

The axial inlet of the centrifugal pump is the effective working area of the impeller, and the fluid enters the volute in the form of swirling flow and is discharged immediately, thereby achieving the purpose of improving the efficiency of liquid delivery.

When the flow rate is constant, the thickness of the formed liquid ring is determined by the pressure of the fluid entering the cyclone cylinder and the pressure of the vacuum pump connected to the suction pipe. In order to facilitate the adjustment of the pressure of the fluid entering the cyclone cylinder, preferably, the A replaceable nozzle is installed in the barrel. The setting of the nozzle can further increase the pressure of the fluid, and nozzles of different sizes can be replaced as required. The inlet size of the nozzle remains unchanged, and the outlet size can be selected in various ways to meet the use requirements under different flow rates.

In order to facilitate the installation and replacement of the nozzle, preferably, the inlet of the nozzle is turned outward to form a fixed ring, and the inner wall of the feed pipe is provided with an annular step supporting the fixed ring to position the nozzle. The annular step can be formed by connecting two tubes with different inner diameters. The feed tube includes: a thin-walled rectangular tube and a thick-walled rectangular tube located below and connected to the thin-walled rectangular tube. The thick-walled rectangular tube The other end of the nozzle is connected to the swirl tube, the nozzle is embedded in the thick-walled rectangular tube, and is fixed in the feed tube by the fixing ring on the upper part of the nozzle.

In order to make the fluid tangent to the inner wall of the swirl cylinder as much as possible, preferably, the feed pipe includes a variable section section connected to the external pipeline and a rectangular communication pipe connected to the variable section section for installing nozzles, the The inlet of the variable cross-section section is circular, and the outlet is rectangular. The diameter of the variable cross-section section gradually decreases along the liquid inlet direction. Compared with the circular tube, the rectangular connecting tube has at least one side that is completely tangent to the cylinder wall, so that the fluid can be as close as possible to the inner wall of the swirl cylinder and the swirl effect can be improved.

Further preferably, one side of the rectangular communication pipe is tangent to the wall of the swirl cylinder, the long side of the cross section of the rectangular communication pipe falls on this side, and the long side a of the rectangular communication pipe Satisfy b<a<3b with broadside b. The above-mentioned ratio settings not only ensure the liquid intake but also ensure that the fluid enters the cyclone cylinder tangentially as much as possible.

In order to allow the fluid ejected from the nozzle to enter tangentially against the inner wall of the swirl cylinder, preferably, the cross-section of the nozzle is rectangular, and the diameter of the nozzle is gradually reduced. The tangential side abuts against one side of the nozzle. Then it enters the nozzle, the outlet diameter of the nozzle is smaller than the inlet of the nozzle, the flow velocity of the fluid increases after passing through the nozzle, and flows into the cylinder along the circumferential direction of the cylinder.

In order not to damage the airflow distribution of the swirling flow, preferably, an end cover is installed at the end of the swirl tube connected to the suction pipe, and the outlet end of the suction pipe is fixed at the center of the end cover.

The larger the air extraction pipe is set, the better the air extraction effect, but too large an air extraction pipe will lead to more liquid entering the vacuum pump. Therefore, in order to take into account efficiency, preferably, the inner diameter of the cyclone cylinder is D, and the suction pipe The inner diameter of the trachea is d, satisfying 0.1D<d<0.2D.

In order to reduce the volume of the present invention while ensuring the efficiency of gas-liquid separation, preferably, the axial direction from the tangential outlet of the feed pipe on the cyclone to the axial inlet of the centrifugal pump (the effective working area of the impeller) The effective length is L, and the inner diameter of the swirl cylinder is D, satisfying D<L<2D.

Preferably, the gap between the blades of the impeller and the inner wall of the volute is 0.3-1 mm, the gap between the side of the impeller disc of the impeller away from the swirl tube and the end surface of the volute is 0.3-1 mm, and the number of blades is 4 to 10, the above structure can reduce the head loss and improve the working efficiency of the impeller.

The impeller includes an impeller disc fixed to the drive shaft. The impeller disc is provided with blades on the side facing the swirl cylinder. The function of the blades is to pressurize and transport the liquid. The closed blades are more efficient, and the open impellers are easy to clean , the blade of the present invention is open or semi-open.

The swirl cylinder is fixedly connected with the axial inlet on the volute through a threaded joint with an inclined surface, which is convenient for disassembly and assembly. The inner diameter of the cyclone is equal to the diameter of the axial inlet. The cyclone cylinder is provided with an opening where it is connected to the feed pipe, one end of the cyclone cylinder is connected with a flat cover, and the other end is connected with a joint flange.

Beneficial effects of the present invention:

The invention combines the gas-liquid cyclone separation with the centrifugal pump, and realizes the two functions of gas-liquid separation and fluid transportation as a whole. The gas is separated before entering the impeller area, which is not easy to cause blockage of the pump inlet, and the gas is not easy to be blocked by the impeller. Take away, the degassing ability is stronger, and the formation of a low-pressure area in the center of the cyclone is also conducive to the separation of gas dissolved in the liquid, further improving the gas-liquid separation effect.

Description of drawings

Fig. 1 is a schematic sectional view of the centrifugal pump of the pre-cyclone gas-liquid separator of the present invention.

Fig. 2 is a schematic diagram of a part of the three-dimensional structure of the centrifugal pump of the front cyclone gas-liquid separator of the present invention.

FIG. 3 is a schematic cross-sectional view of FIG. 2 .

Fig. 4 is a schematic perspective view of the three-dimensional structure of the nozzle of the centrifugal pump of the pre-swirl gas-liquid separator of the present invention.

Fig. 5 is a schematic perspective view of the three-dimensional structure of the impeller of the centrifugal pump of the pre-swirl gas-liquid separator of the present invention.

detailed description

As shown in FIGS. 1 to 5 , the centrifugal pump of the front cyclone gas-liquid separator of this embodiment includes: a centrifugal pump and a cyclone cylinder 3 connected to each other.

The centrifugal pump includes a volute 8 with an axial inlet and a built-in pump shaft 4, and an impeller 14 fixedly connected to the pump shaft 4 for discharging liquid in the volute 8. An outlet 9 (tangential outlet) is provided above the volute 8. The end cover of the volute 8 is a connecting frame 15, the impeller 14 is provided with a blade 7 facing the side of the swirl tube 3, the gap between the blade 7 and the inner wall of the volute 8 is 0.5mm, and the side of the impeller 14 away from the swirl tube 3 is connected to the The gap of frame 15 is 0.5mm, and blade 7 is an open blade, gets 6 in the present embodiment.

The swirl tube 3 includes an end cap 1 and a cylinder wall 2. The open end of the swirl tube 3 is connected with a threaded joint 13, and the axial inlet of the volute 8 is connected with a threaded joint 2 6. The swirl tube 3 and the The volutes 8 are fixedly connected by threaded joints 5 .

An exhaust pipe 10 is fixed on the end cover 1, the exhaust pipe 10 is a straight pipe, one end passes through the end cover 1, and the other end communicates with the inside of the swirl tube 3 through the end cover 1, the inner diameter of the exhaust tube 10 is d, and the diameter of the swirl tube 3 The inner diameter is D, satisfying d=0.15D.

The effective length from the end cover 1 to the inlet of the blade 7 is L, and L is the axial length of the path of the fluid swirl. The larger the L, the longer the flow of the swirl, but if the length is too large, the flow rate of the water flow will decrease, and the fluid will The state of swirling flow cannot be maintained, and the swirling flow separation is no longer performed. Therefore, in this embodiment, L=1.5D is satisfied.

The swirl tube 3 is provided with a tangential inlet, and the tangential inlet is connected with the feed pipe 12 . The feeding pipe is made up of a variable section tube 16 and a rectangular tube 17. The upper end section of the variable section tube 16 is a circle, and the lower end section is a rectangle. The rectangular tube 17 is composed of upper and lower sections, the upper part is a thin-walled rectangular tube 18, and the lower part is a thick-walled rectangular tube 21. The thin-walled rectangular tube 18 and the thick-walled rectangular tube 21 form a stepped structure at the joint, and the nozzle 11 is composed of a fixed ring 19 and a spout 20 . The nozzle 11 is fixed on the stepped structure between the thin-walled rectangular tube 18 and the thick-walled rectangular tube 21 by means of a fixing ring 19 .

The cross-sections of the flow passages in the nozzle 11 are all rectangular, and the cross-sectional area of the inlet is larger, and the cross-sectional area gradually decreases toward the outlet. The size of the inlet cross-section of the nozzle 11 remains unchanged, and the size of the outlet cross-section can be selected in many ways to meet the use requirements under different flow rates.

During the actual work of this embodiment, the exhaust pipe 10 is externally connected with a vacuum pump. The liquid enters from the external pipeline through the feed pipe 12. After flowing through the nozzle 11, the flow velocity increases, and the fluid flows into the swirl cylinder 3 at high speed tangentially to form a high-speed rotating liquid ring. The impeller 14 is coaxially linked with the pump shaft 4. Driven by high-speed rotation, the thickness of the liquid ring can be adjusted through the fluid flow rate and the vacuum pump. Under the joint action of the fluid in the cyclone and the external vacuum pump, the free and dissolved gases in the liquid are separated and removed through the exhaust pipe 10. After degassing The liquid enters the volute 8 in the form of swirling flow, and the impeller 14 in the volute 8 drives the liquid to rotate, gives the liquid pressure and discharges it through the outlet 9 of the volute 8 .

Claims (7)

1. a centrifugal pump of a pre-swirl type gas-liquid separator, comprising a feed pipe, a swirl cylinder, an air extraction pipe and a centrifugal pump, it is characterized in that the cylinder wall of the feed pipe and the swirl cylinder is cut One end of the swirl cylinder close to the feed pipe is connected to the suction pipe, and the other end is connected to the axial inlet of the centrifugal pump; a replaceable nozzle is installed in the feed pipe; The feed pipe includes a variable-section section connected to the external pipeline and a rectangular connecting pipe connected to the variable-section section for installing nozzles. The inlet of the variable-section section is circular, and the outlet is rectangular. The variable-section section The caliber gradually shrinks along the liquid inlet direction; One side of the rectangular communication pipe is tangent to the wall of the swirl cylinder, the cross-section of the nozzle is rectangular, and the diameter of the nozzle is gradually reduced, and the rectangular communication pipe is in contact with the wall of the swirl cylinder. The cut side abuts against one side of the nozzle. 2. The centrifugal pump of the pre-swirl type gas-liquid separator as claimed in claim 1, wherein the inlet of the nozzle is turned outward to form a fixed ring, and the inner wall of the feed pipe is provided with a support The retaining ring described above is used to position the annular step of the nozzle. 3. the centrifugal pump of pre-swirl type gas-liquid separator as claimed in claim 2, is characterized in that, the long side of the cross section of described rectangular connecting pipe falls on this side, and the long side of described rectangular connecting pipe Side a and broad side b satisfy b<a<3b. 4. The centrifugal pump of the pre-swirl type gas-liquid separator as claimed in claim 1, wherein an end cover is installed on the end of the swirl tube connected to the air extraction pipe, and the outlet end of the air extraction pipe is fixed in the center of the end cap. 5. The centrifugal pump of the pre-swirl gas-liquid separator according to claim 1, characterized in that, the vacuum pump is connected to the suction pipe. 6. The centrifugal pump of the pre-swirl type gas-liquid separator as claimed in claim 1, characterized in that, the tangential outlet of the feed pipe on the swirl cylinder is to the axial direction of the axial inlet of the centrifugal pump. The effective length is L, and the inner diameter of the swirl cylinder is D, satisfying D<L<2D. 7. the centrifugal pump of pre-swirl type gas-liquid separator as claimed in claim 1, is characterized in that, described centrifugal pump comprises the volute that has axial inlet and tangential outlet, is installed in the volute The impeller and the driving shaft of the impeller, the gap between the blade of the impeller and the inner wall of the volute is 0.3-1 mm, the gap between the side of the impeller disc of the impeller far away from the swirl tube and the end surface of the volute is 0.3-1 mm, the blade The number of slices is 4-10.