WO2021010976A1

WO2021010976A1 - Centrifugal bubble removal device

Info

Publication number: WO2021010976A1
Application number: PCT/US2019/041867
Authority: WO
Inventors: Grant David GARFIELD; Ziv SEEMANN; Yuri DRUTMAN; Shmuel Izhak BORENSTAIN
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2019-07-15
Filing date: 2019-07-15
Publication date: 2021-01-21

Abstract

Examples of bubble removal device are described. In an example, the bubble removal device may include a chamber with a curved external wall. A fluid inlet may receive a fluid under a force that rotates the fluid within the chamber and generates a pressure within the chamber. The fluid rotation may develop a centrifugal force to separate gas bubbles from the fluid. An air outlet may remove the separated gas bubbles from the chamber. A fluid outlet may be located at a tangent to the external wall and in-line with the fluid rotation.

Description

CENTRIFUGAL BUBBLE REMOVAL DEVICE

BACKGROUND

[0001] Fluids may be used in various applications. For example, printing devices may print on a print media using fluids. In some examples, a printing device may apply a liquid ink to the print media.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Various examples will be described below by referring to the following figures.

[0003] Figure 1 is an isometric view illustrating an example of a bubble removal device;

[0004] Figure 2 is a plan view illustrating an example of fluid rotation within the bubble removal device;

[0005] Figure 3 is a cross section elevation view illustrating an example of a bubble removal device;

[0006] Figure 4 is a cross section elevation view illustrating another example of a bubble removal device;

[0007] Figure 5 is a block diagram of an example of an apparatus with a bubble removal device; and

[0008] Figure 6 is a flow diagram illustrating an example of a method for bubble removal.

[0009] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover the drawings provide examples and/or implementations in accordance with the description; however, the description is not limited to the examples and/or implementations provided in the drawings.

DETAILED DESCRIPTION

[0010] The techniques described herein relate to centrifugal bubble removal. In some examples, a printing device - including printing presses, printers, copiers, fax machines, multifunction devices including additional scanning, copying, and finishing functions, all-in-one devices, pad printers to print images on three dimensional objects, and 3D printers - may apply a print substance, which can include printing agents or colorants, to a print media. For example, a printing device may apply a fluid to the print media. In some examples, the fluid may be a liquid ink.

[0011] In some cases, the fluid that is to be applied to the print media may have gas bubbles (e.g., air). For instance, bubbles may be unintentionally introduced to an ink supply. Bubbles in the ink supply may cause print defects. For example, bubbles may be transferred to the print media during printing.

[0012] A centrifugal bubble removal device is described herein. The bubble removal device may include a cylindrical chamber with a fluid inlet for supplying a fluid (e.g., liquid ink). The bubble removal device may also include a fluid outlet located at the bottom of the bubble removal device and an air outlet located at the top of the bubble removal device.

[0013] The fluid may be introduced into the bubble removal device under pressure. The pressurized fluid may contact the curved wall of the chamber, which creates a rotating motion of the fluid in the chamber. The bubble removal device utilizes centrifugal force (rotating motion) to direct the fluid outwards from the fluid inlet to the exterior wall of the cylindrical chamber. The centrifugal force may cause gas bubbles to separate from the fluid and rise to the top of the bubble removal device. The separated gas bubbles may then exit from the bubble removal device through the air outlet. [0014] The centrifugal force is generated by the pressure of the fluid entering the bubble removal device and contacting the curved exterior wall. Therefore, the bubble removal device may be passive and may not use additional energy to separate gas bubbles from the fluid.

[0015] Figure 1 is an isometric view illustrating an example of a bubble removal device 102. The bubble removal device 102 may also be referred to as a bubble trap, a debubbler or a degasser.

[0016] In some examples, the bubble removal device 102 may be used in a printing device (e.g., printing press, printer, copier, etc.) that applies a fluid to a print media (e.g., a paper sheet). In other examples, the bubble removal device 102 may be used in other applications in which bubble removal from a fluid is performed.

[0017] In the case of printing, a liquid ink may be pumped from an ink supply tank to other components of the printing device. For example, in the case of a printing press, a diluted liquid ink may be pumped to a binary ink developer (BID) for development before printing. Gas bubbles may travel in the liquid ink through the ink supply path. The gas bubbles may disrupt the ink development that happens within the BID, causing a defect to be seen on prints. The bubble removal device 102 may separate and remove the bubbles from the ink supply to reduce the occurrence of these defects and deliver bubble-free ink to the BID.

[0018] The bubble removal device 102 may include a chamber 104. The chamber 104 may have a curved external wall 106. For example, the chamber 104 may be cylindrical. The external wall 106 of the chamber 104 may form an interior cavity. The chamber 104 may be referred to as the body of the bubble removal device 102.

[0019] The bubble removal device 102 may include a fluid inlet 108. In some examples, the fluid inlet 108 may be located at or near the top of the external wall 106. In some examples, the fluid inlet 108 may form a hole or other orifice in the side of the exterior wall 106. In some examples, the fluid inlet 108 may be located at a tangent to the external wall 106. For example, the fluid inlet 108 may be oriented on the external wall 106 such that a fluid entering the fluid inlet 108 moves tangential to the interior surface of the external wall 106. An example of an orientation of the fluid inlet 108 with respect to the chamber 104 is illustrated in Figure 2.

[0020] In some examples, the fluid inlet 108 may include a structure through which a fluid moves into the bubble removal device 102. For example, the fluid inlet 108 may be a tube, pipe, channel, duct or other mechanism to transport fluid. In some examples, the fluid inlet 108 may include fittings to attach to other fluid transport mechanisms.

[0021] The bubble removal device 102 may include a fluid outlet 112. In some examples, the fluid outlet 112 may be located at or near the bottom of the external wall 106. In some examples, the fluid outlet 112 may form a hole or other orifice in the side of the fluid outlet 112. In some examples, the fluid outlet 112 may be located at a tangent to the external wall 106. For example, the fluid outlet 112 may be oriented on the external wall 106 such that a fluid exiting the fluid outlet 112 moves tangential to the interior surface of the external wall 106. An example of an orientation of the fluid outlet 112 with respect to the chamber 104 is illustrated in Figure 2.

[0022] In some examples, the fluid outlet 112 may be in-line with fluid rotation within the chamber 104. For example, as a fluid enters the chamber 104 through the fluid inlet 108 at a tangent to the external wall 106, the fluid may rotate within the chamber 104. The orientation and location of the fluid outlet 112 on the exterior wall 106 may be in-line with the fluid rotation as illustrated in Figure 2. This in-line orientation of the fluid outlet 112 with respect to the fluid rotation may improve the flow of the fluid through the bubble removal device 102 by reducing turbulence within the rotating fluid as it exits the bubble removal device 102. Furthermore, this in-line orientation of the fluid outlet 112 may reduce the likelihood of introducing additional bubbles into the fluid by reducing turbulence of the fluid within the chamber 104.

[0023] In some examples, the chamber 104 of the bubble removal device 102 may be stationary. For example, the bubble removal device 102 may be installed in an apparatus (e.g., a printing device) such that the chamber 104 is stationary. In these examples, fluid rotation within the chamber 104 may be generated by the force of the fluid entering the fluid inlet 108 and being directed to a rotating movement by the curved exterior wall 106.

[0024] In some examples, the fluid outlet 112 may include a structure through which fluid moves out of the bubble removal device 102. For example, the fluid outlet 112 may be a tube, pipe, channel, duct or other mechanism to transport fluid. In some examples, the fluid outlet 112 may include fittings to attach to other fluid transport mechanisms.

[0025] The bubble removal device 102 may also include a top portion and a bottom portion. When the bubble removal device 102 is in operation, the top portion may be oriented upward with respect to gravity and the bottom portion may be oriented downward with respect to gravity. In some examples, the top portion may be a flat plate attached to the top of the curved exterior wall 106 of the chamber 104. In other examples, the top portion may be a dome, cone or other shape.

[0026] In some examples, the bottom portion may be a flat plate attached to the bottom of the curved exterior wall 106 of the chamber 104. In other examples, the bottom portion may be a dome, cone or other shape. It should be noted that in some examples, the top portion and the bottom portion may have different shapes. For example, the top portion may have a dome shape and the bottom portion may have a flat plate shape.

[0027] The bubble removal device 102 may include an air outlet 110. In some examples, the air outlet 110 may be located on the top portion of the bubble removal device 102. In some examples, the air outlet 110 may form a hole or other orifice in the top portion of the bubble removal device 102. In some examples, the air outlet 110 may be located in the center of the top portion.

[0028] During operation of the bubble removal device 102, fluid may enter the fluid inlet 108 under a force. For example, a pump or other mechanism may force the fluid to enter the fluid inlet. In this case, the fluid may move through the fluid inlet 108 and into the chamber 104 under a positive pressure. The fluid entering the bubble removal device 102 may be a mixture of a liquid (e.g., liquid ink) and gas bubbles. [0029] The force of the fluid entering the fluid inlet 108 may cause the fluid to rotate within the chamber 104. For example, because the fluid inlet 108 is oriented tangential to the exterior wall 106, the fluid may move along the curved exterior wall 106 upon entering the chamber 104. This motion may cause fluid in the chamber 104 to rotate. This fluid rotation may form a vortex within the chamber 104.

[0030] The rotating motion of the fluid may cause fluid to move outward by centrifugal force. Because of the buoyancy of gas bubbles in the fluid, the centrifugal force may cause the gas bubbles to move toward the center of chamber 104. The buoyancy of the gas bubbles may also cause the gas bubbles to rise toward the top portion of the bubble removal device 102 as the fluid rotates. The separated gas bubbles may rise to the top of the bubble removal device 102.

[0031] The separated gas bubbles may be removed from the bubble removal device 102 through the air outlet 110. In some examples, the separated gas bubbles may be pumped out of the bubble removal device 102 through the air outlet 110. In other examples, a positive pressure within the chamber 104 may force the separated gas bubbles out of the air outlet 110. In other examples, the positive pressure in the bubble removal device 102 and the buoyancy of the separated gas bubbles force the separated gas bubbles out of the air outlet 110.

[0032] In some examples, the fluid may fill the entire cavity of the chamber 104 up to the air outlet 110. In this case, the force of the fluid entering the fluid inlet 108 may generate a pressure within the chamber 104. The pressure of the fluid entering chamber 104 may create a positive pressure within the bubble removal device 102. The positive pressure may force the separated gas bubbles out of the air outlet 110. It should be noted that in some cases, a mixture of the separated gas bubbles and a portion of the fluid exits out of the air outlet 110. In other words, the air outlet 110 may transport a mixture of gas (e.g., separated gas bubbles) and liquid (e.g., liquid ink) out of the bubble removal device 102.

[0033] The degassed fluid (e.g., debubbled liquid ink) may exit through the fluid outlet 112. For example, the fluid at the bottom of the bubble removal device 102 may be separated from the gas bubbles. This degassed fluid may be removed from the bottom of the bubble removal device 102 through the fluid outlet 112.

[0034] In some examples, the components of the bubble removal device 102 may be constructed from metal (e.g., steel, stainless steel, copper, aluminum, titanium, etc.) or plastics. In some examples, the bubble removal device 102 may be fabricated by machining, 3D printing, and/or molding (e.g., injection molding).

[0035] In some examples, the bubble removal device 102 may be fabricated in multiple parts. For example, the chamber 104 may be separated into an upper portion and a lower portion that are separate components. In this example, a flange with fasteners (e.g., screws, bolts) may connect the upper portion and lower portion. An O-ring located between the upper portion and lower portion may seal the chamber 104.

[0036] In other examples, the bubble removal device 102 may be fabricated as a single part. For example, the bubble removal device 102 may be 3D printed as a single part. In another example, the components of the bubble removal device 102 may be welded together to form a single part.

[0037] In some examples, the connections for the fluid inlet 108, the fluid outlet 112 and the air outlet 110 may be molded or machined as part of the bubble removal device 102. In other examples, the connections for the fluid inlet 108, the fluid outlet 112 and the air outlet 110 may be separate threaded fittings that are attached to the bubble removal device 102 during assembly.

[0038] Figure 2 is a plan view illustrating an example of fluid rotation 116 within the bubble removal device 102. As described above, the bubble removal device 102 may include a chamber 104 with a curved exterior wall 106. The bubble removal device 102 may also include a fluid inlet 108 and a fluid outlet 112.

[0039] In some examples, the curved exterior wall 106 may be a cylinder with a circular cross section. Fluid within the chamber 104 may rotate about the center 120 of the chamber 104.

[0040] In some examples, the fluid inlet 108 may be located at a tangent to the external wall 106. For example, the fluid inlet 108 may be oriented on the external wall 106 such that intake fluid 114 entering the fluid inlet 108 moves tangential to the interior surface of the external wall 106. The intake fluid 114 may enter the chamber 104 under pressure. Upon contacting the curved exterior wall 106, the pressure of the intake fluid 114 may cause the fluid within the chamber to rotate.

[0041] In some examples, the fluid outlet 112 may be located at a tangent to the external wall 106. For example, the fluid outlet 112 may be oriented on the external wall 106 such that the exit fluid 118 moves tangential to the interior surface of the external wall 106.

[0042] Figure 3 is a cross section elevation view illustrating an example of a bubble removal device 302. The bubble removal device 302 may be implemented in accordance with the bubble removal device 102 of Figure 1.

[0043] In the example illustrated in Figure 3, the chamber 304 may include a curved external wall 306. The bubble removal device 302 may include a fluid inlet 308 located at or near the top of the external wall 306. The bubble removal device 302 may include a fluid outlet 312 located at or near the bottom of the external wall 306. The fluid inlet 308 and the fluid outlet 312 may be oriented tangential to the external wall 306.

[0044] The bubble removal device 302 may include a top portion 324 and a bottom portion 322. In some examples, the top portion 324 may be a flat, circular plate attached to the top of the curved exterior wall 306. In other examples, the top portion 324 may be a dome, cone or other shape. In some examples, the bottom portion 322 may be a flat, circular plate attached to the bottom of the curved exterior wall 306. In other examples, the bottom portion 322 may be a dome, cone or other shape.

[0045] The bubble removal device 302 may include an air outlet 310. In some examples, the air outlet 310 may be located on the top portion 324 of the bubble removal device 302. In some examples, the air outlet 310 may be located in the center of the top portion 324.

[0046] It should be noted that the curved wall 306 and bottom portion 322 may form a cavity to contain fluid entering the chamber 304. In some examples, the fluid may completely fill the chamber 304 up to the top portion 324. [0047] The fluid entering the chamber 304 may be a mixture of liquid and gas bubbles. Separated gas bubbles may exit through the air outlet 310 and degassed fluid may exit through the fluid outlet 312. The bubble removal may be performed as described in connection with Figure 1.

[0048] Figure 4 is a cross section elevation view illustrating another example of a bubble removal device 402. The bubble removal device 402 may be implemented in accordance with the bubble removal device 102 of Figure 1.

[0049] In the example illustrated in Figure 4, the chamber 404 may include a curved external wall 406. The bubble removal device 402 may include a fluid inlet 408 and fluid outlet 412 oriented tangential to the external wall 406. The bubble removal device 402 may also include a top portion 424 and a bottom portion 422, as described in Figure 3. The bubble removal device 402 may further include an air outlet 410 located on the top portion 424 of the bubble removal device 402.

[0050] In some examples, the bubble removal device 402 may include a central shaft component 426 located within the chamber 404. In some examples, the central shaft component 426 may have a cylindrical shape. In other examples, the central shaft component 426 may be tapered to form a conical shape with a larger base at the bottom.

[0051] The central shaft component 426 may connect to the bottom portion 422 of the chamber 404. For example, the central shaft component 426 may be bonded (e.g., welded, adhesive) to the bottom portion 422. In another example, the central shaft component 426 may be attached to the bottom portion 422 with fasteners (e.g., screws, bolts, etc.). In yet another example, the central shaft component 426 may be fabricated (e.g., 3D printed, injection molded) with the bottom portion 422 to form a single component. In some examples, the central shaft component 426 may be located concentric with the center of the curved external wall 406.

[0052] In some examples, the central shaft component 426 may be sized to prevent an air pocket from forming as the fluid rotates within the chamber 404. For example, the fluid rotation may form a vortex. A cavity of air (referred to as an air pocket) may form within the chamber 404 as the fluid rotates. This air pocket may introduce more bubbles into the fluid. To prevent the addition of bubbles due to the fluid rotation, the central shaft component 426 may be used to fill any air pocket that would form. Therefore, the fluid may rotate around the chamber 404 to create a centrifugal force that separates gas bubbles from the liquid, but the central shaft component 426 prevents additional bubbles from being added to the fluid during the fluid rotation.

[0053] Figure 5 is a block diagram of an example of an apparatus 501 with a bubble removal device 502. Examples of the apparatus 501 include printing devices (e.g., printing presses, printers (e.g., ink-jet printers), copiers, fax machines, multifunction devices, all-in-one devices, pad printers to print images on three dimensional objects, and 3D printers). In other examples, the apparatus 501 may be used in applications where gas bubbles are to be separated from a fluid.

[0054] In some examples, the apparatus 501 may include and/or may be coupled to a processor and/or a memory. In some examples, the apparatus 501 may include a display and/or an input/output interface. In some examples, the apparatus 501 may be in communication with (e.g., coupled to, have a communication link with) an external device (e.g., smartphone, personal computer, a server computer, a smartphone, a tablet computer, etc.). The apparatus 501 may include additional components (not shown) and/or some of the components described herein may be removed and/or modified without departing from the scope of this disclosure.

[0055] The apparatus 501 may include a bubble removal device 502 that may be implemented in accordance with the bubble removal device 102 described in Figure 1. For example, the bubble removal device 502 may include a chamber 504 with a curved external wall, a fluid inlet 508 to receive a fluid at a tangent to the external wall, an air outlet 510 to remove separated gas bubbles from the chamber 504, and a fluid outlet 512 located at a tangent to the external wall and in-line with fluid rotation within the chamber 504.

[0056] In some examples, the apparatus 501 may include a fluid supply tank 532. For example, the fluid supply tank 532 may store a liquid substance. In the case of a printing device, the fluid supply tank 532 may store a liquid ink. In some cases, the fluid in the fluid supply tank 532 may include gas bubbles. For example, bubbles may be mixed with the fluid when the fluid enters the fluid supply tank 532. In other examples, bubbles may mix with the fluid that is returned to the fluid supply tank 532 after the apparatus 501 performs an operation (e.g., printing) using the fluid.

[0057] In some examples, the apparatus 501 may include a pump 534 to supply the fluid to the bubble removal device 502. The pump 534 may move the fluid from the fluid supply tank 532 to the bubble removal device 502 through a supply line 536. In some examples, the pump 534 may supply the fluid to the bubble removal device 502 with a force. For example, the pump may exert pressure on the fluid as it enters the bubble removal device 502. The force on the fluid entering the bubble removal device 502 may rotate the fluid within the chamber 504 and may generate a pressure within the chamber 504. The fluid rotation in the bubble removal device 502 may develop a centrifugal force to separate gas bubbles from the fluid.

[0058] Degassed fluid may exit the bubble removal device 502 through the fluid outlet 538. A fluid outlet line 538 may supply the degassed fluid to a fluid storage tank 542. In some examples, the pressure from the pump 534 may force the degassed fluid out of the bubble removal device 502 and through the fluid outlet line 538.

[0059] In some examples, the apparatus 501 may include a return line 540 to return a mixture of the separated gas bubbles and a portion of the fluid from the air outlet 510 to the fluid supply tank 532. For example, the pressure of the fluid entering chamber 504 may create a positive pressure within the bubble removal device 502. The positive pressure may force the separated gas bubbles out of the air outlet 510. A mixture of the separated gas bubbles and a portion of the fluid may exit out of the air outlet 510. The return line 540 coupled to the air outlet 510 may transport the mixture of gas (e.g., separated gas bubbles) and liquid (e.g., liquid ink) out of the bubble removal device 502 and back to the fluid supply tank 532.

[0060] In the case of a printing device, the bubble removal device 502 may be installed in the printing device. For example, the bubble removal device 502 may be installed in a printing press in-line of each ink supply line (e.g., supply line 536) from an ink tank (e.g., fluid supply tank 532) to a binary ink developer (BID) for development of the ink before printing. The bubble removal device 502 may receive liquid ink from the pump 534 of the ink tank. The bubble removal device 502 may output bubble-free fluid (e.g., liquid ink) to the BID from the fluid outlet 512. The bubble removal device 502 may return a small amount of ink along with the bubbles removed from the ink back to the ink tank by way of the air outlet 510 and return line 540.

[0061] Figure 6 is a flow diagram illustrating an example of a method 600 for bubble removal. The method 600 for bubble removal may be performed by, for example, the bubble removal device 102.

[0062] The bubble removal device 102 may receive 602 a fluid at a fluid inlet 108 of a chamber 104 with a curved external wall 106. The fluid inlet 108 may be located at a tangent to the external wall 106. In some examples, the external wall 106 may form a cylinder. The fluid may fill the chamber 104.

[0063] The bubble removal device 102 may rotate 604 the fluid within the chamber 104 with a positive pressure on the fluid entering the chamber 104 and fluid contact on the external wall 106. In some examples, an external pump may force the fluid to enter the fluid inlet 108. The pressure of the fluid entering the chamber 104 may generate a positive pressure within the chamber 104. The velocity of the fluid striking the external wall 106 may cause the fluid within the chamber 104 to rotate.

[0064] The bubble removal device 102 may separate 606 gas bubbles from the fluid with a centrifugal force developed by fluid rotation. For example, centrifugal force of the rotating fluid may direct the fluid outwards from the main fluid inlet 108 to the exterior wall 106 of the chamber 104. The centrifugal force may cause gas bubbles to separate from the fluid and rise to the top of the bubble removal device 102.

[0065] The bubble removal device 102 may remove 608 the separated gas bubbles from the chamber 104 through an air outlet 110 located at a top portion of the chamber 104. For example, the positive pressure in the bubble removal device 102 and the buoyancy of the separated gas bubbles may force the separated gas bubbles out of the air outlet 110. In some examples, a mixture of the separated gas bubbles and a portion of the fluid exits out of the air outlet 110.

[0066] The bubble removal device 102 may remove 610 degassed fluid through a fluid outlet 112 located at a tangent to the external wall 106 and in-line with the fluid rotation. For example, the fluid at the bottom of the bubble removal device 102 may be separated from the gas bubbles. This degassed fluid may be removed 610 from the bottom of the bubble removal device 102 through the fluid outlet 112.

[0067] It should be noted that while various examples of systems and methods are described herein, the disclosure should not be limited to the examples. Variations of the examples described herein may be implemented within the scope of the disclosure. For example, functions, aspects, or elements of the examples described herein may be omitted or combined.

Claims

1. A bubble removal device, comprising:

a chamber having a curved external wall;

a fluid inlet to receive a fluid under a force that rotates the fluid within the chamber and generates a pressure within the chamber, the fluid rotation developing a centrifugal force to separate gas bubbles from the fluid;

an air outlet to remove the separated gas bubbles from the chamber; and a fluid outlet located at a tangent to the external wall and in-line with the fluid rotation.

2. The bubble removal device of claim 1 , wherein the fluid inlet is located at a tangent to the external wall.

3. The bubble removal device of claim 1 , wherein the fluid inlet is located at a top of the external wall and the fluid outlet is located at a bottom of the external wall.

4. The bubble removal device of claim 1 , wherein the air outlet is located at a top portion of the bubble removal device.

5. The bubble removal device of claim 1 , further comprising a central shaft component located within the chamber.

6. The bubble removal device of claim 5, wherein the central shaft component is connected to a bottom portion of the chamber concentric with a center of the curved external wall.

7. The bubble removal device of claim 5, wherein the central shaft component is sized to prevent an air pocket from forming as the fluid rotates within the chamber.

8. The bubble removal device of claim 1 , wherein the gas bubbles move toward the center of the chamber as the fluid rotates within the chamber.

9. The bubble removal device of claim 1 , wherein the fluid fills the chamber up to the air outlet.

10. A method, comprising:

receiving a fluid at a fluid inlet of a chamber with a curved external wall, the fluid inlet being located at a tangent to the external wall;

rotating the fluid within the chamber with a positive pressure on the fluid entering the chamber and fluid contact on the external wall;

separating gas bubbles from the fluid with a centrifugal force developed by fluid rotation;

removing the separated gas bubbles from the chamber through an air outlet located at a top portion of the chamber; and

removing a degassed fluid through a fluid outlet located at a tangent to the external wall and in-line with the fluid rotation.

1 1. The method of claim 10, wherein a mixture of the separated gas bubbles and a portion of the fluid exits out of the air outlet.

12. The method of claim 10, wherein the positive pressure in the bubble removal device and buoyancy of the separated gas bubbles force the separated gas bubbles out of the air outlet.

13. An apparatus, comprising:

a bubble removal device having a chamber with a curved external wall, a fluid inlet to receive a fluid at a tangent to the external wall, an air outlet to remove separated gas bubbles from the chamber, and a fluid outlet located at a tangent to the external wall and in-line with fluid rotation within the chamber; and

a pump to supply the fluid to the bubble removal device with a force that rotates the fluid within the chamber and generates a pressure within the chamber, the fluid rotation developing a centrifugal force to separate gas bubbles from the fluid.

14. The apparatus of claim 13, further comprising a return line to return a mixture of the separated gas bubbles and a portion of the fluid from the air outlet to a fluid supply tank.

15. The apparatus of claim 13, wherein the bubble removal device outputs a bubble-free fluid from the fluid outlet.