Gregory C Andrews
Land Surveyors in Sandy, UT

6778636, Aug 17, 2004

Jun 6, 2002

10/165262

Gregory C. Andrews - Sandy UT

Varian Medical Systems, Inc. - Palo Alto CA

G21K 104

378150, 378147

An adjustable collimator for reducing the emission of off-focus radiation and for use in selectively altering the size of an x-ray beam produced by an x-ray tube is disclosed. The collimator comprises a base member supporting a collimator plate that defines a first x-ray passing region. A radiation blocking member is operably attached to a moveable block that is disposed in the base member such that selective movement of the block causes the blocking member to obstruct and thereby reduce the size of the first region and create a smaller-dimensioned second region through which x-rays can pass.

6480571, Nov 12, 2002

Jun 20, 2000

09/597034

Gregory C. Andrews - Sandy UT

Varian Medical Systems, Inc. - Palo Alto CA

H01J 3510

378131, 378132

An anode drive assembly for use in an x-ray tube having a rotating anode is disclosed. The anode drive assembly is comprised of a bearing assembly that provides rotational support to a rotor assembly. The rotor assembly is connected to the rotating anode, and rotation is induced in the rotor by way of an inductive motor. The bearing assembly is interconnected with the rotor assembly via a bearing hub. The bearing hub is comprised of a material having a coefficient of thermal expansion (CTE) that is intermediate to that of the components connected directly to the anode, and to the bearing shaft component. This provides a gradual transition in CTE along the conductive path between the anode and the bearing shaft so as to reduce the occurrence of thermal expansion rate disparities between adjacent components.

6519318, Feb 11, 2003

Sep 7, 2000

09/656076

Gregory C. Andrews - Sandy UT

Varian Medical Systems, Inc. - Palo Alto CA

H01J 3510

378141, 378121, 378119, 378130

An improved x-ray tube cooling system is disclosed. The system utilizes a shield structure that is connected between a cathode cylinder and an x-ray tube housing and is disposed between the electron source and the target anode. The shield includes a plurality of cooling fins to improve overall cooling of the x-ray tube and the shield so as to extend the life of the x-ray tube and related components. When immersed in a reservoir of coolant fluid, the fins facilitate improved heat transfer by convection from the shield to the to the coolant fluid. The cooling effect achieved with the cooling fins is further augmented by a convective cooling system provided by a plurality of fluid passageways formed within the shield, which are used to provide a fluid path to the coolant. In particular, a cooling unit takes fluid from the reservoir, cools the fluid, then circulates the cooled fluid through the fluid passageways. One or more depressions of “V” shaped cross section defined on the surfaces of the fluid passageways serve to facilitate nucleate boiling of the coolant in the passageway, and thereby materially increase the heat flux through the passageway to the coolant.

6400799, Jun 4, 2002

Jul 12, 1999

09/351579

Gregory C. Andrews - Sandy UT

Varian Medical Systems, Inc. - Palo Alto CA

H01J 3510

378141, 378121, 378119

An improved x-ray tube cooling system is disclosed. The system utilizes a shield structure that is connected between a cathode cylinder and an x-ray tube housing and is disposed between the electron source and the target anode. The shield a plurality of cooling fins to improve overall cooling of the x-ray tube and the shield so as to extend the life of the x-ray tube and related components. When immersed in a reservoir of coolant fluid, the fins facilitate improved heat transfer by convection from the shield to the to the coolant fluid. The cooling effect achieved with the cooling fins is further augmented by a convective cooling system provided by a plurality of passageways formed within the shield, which are used to provide a fluid path to the coolant. In particular, a cooling unit takes fluid from the reservoir, cools the fluid, then circulates the cooled fluid through cooling passages. The coolant is then output from the passageway and directed over the cooling fins.

6366642, Apr 2, 2002

Jan 16, 2001

09/761488

Gregory C. Andrews - Sandy UT

Varian Medical Systems, Inc. - Palo Alto CA

H01J 3510

378130, 378117, 378141

A cooling system for use in conjunction with rotating anode and stationary anode x-ray tubes. The cooling system includes a reservoir containing a volume of coolant in which a portion of the x-ray tube is immersed. A bladder incorporated in the reservoir and in communication with the atmosphere automatically permits thermal expansion of the coolant while maintaining the coolant at atmospheric pressure. An external cooling unit directs a flow of coolant through a pressure drop device proximate to the x-ray tube so that the flowing coolant removes heat from the x-ray tube. Upon exiting the pressure drop device, the heated coolant is directed to the reservoir and ultimately returned to the external cooling unit where heat is removed from the coolant and the coolant then redirected back to the pressure drop device to repeat the cycle. The cooling system includes a pressure switch connected to a pressure tap located upstream of the pressure drop device so that the pressure switch is positioned to sense the pressure of the coolant upstream of the pressure drop device. Simultaneously, the pressure switch is in communication with the coolant disposed in the reservoir.

6693990, Feb 17, 2004

May 14, 2001

09/855591

Gregory C. Andrews - Sandy UT

Varian Medical Systems Technologies, Inc. - Palo Alto CA

H01J 3510

378132, 378119, 378133, 378125, 378127, 378130

A bearing assembly for a rotating anode x-ray device. The bearing assembly includes a shaft having a flange at one end for attachment of the anode thereto. The shaft defines front and rear inner races and includes a plurality of extended surfaces. Front and rear outer race elements define front and rear outer races, respectively, corresponding to the front and rear inner races, respectively, defined by the shaft. The front and rear outer race elements cooperate with the shaft to confine front and rear ball sets which facilitate rotary motion of the shaft. A spacer including extended surfaces assists in the positioning of the front and rear outer race elements in a bearing housing. The extended surfaces of the shaft and spacer, in conjunction with emissive coatings provided on various portions of selected components of the bearing assembly, facilitate a relative improvement in heat transfer out of the bearing assembly.

6751292, Jun 15, 2004

Aug 19, 2002

10/223133

Gregory C. Andrews - Sandy UT
Vaughn Leroy Barrett - West Jordan UT

Varian Medical Systems, Inc. - Palo Alto CA

H01J 3528

378132, 378130

A rotor assembly capable of augmented heat transfer within an x-ray tube is disclosed for preventing heat damage to sensitive tube components. The rotor assembly generally comprises a shaft assembly for supporting the anode, a bearing assembly including a bearing housing and bearing sets for enabling rotation of the shaft assembly, and a magnetic sleeve. The shaft assembly includes a rotor sleeve that receives heat emitted by the anode during tube operation. The rotor sleeve radiates the heat to the magnetic sleeve, which is concentrically disposed within the rotor sleeve. A coolant-filled gap is defined adjacent the inner surface of the magnetic sleeve to receive the heat absorbed by the magnetic sleeve. The inner periphery of the gap is defined by the outer surface of the bearing housing. Emissive and absorptive coatings are disposed on the various surfaces of the rotor sleeve and magnetic sleeve to enhance heat transfer therebetween.

6519317, Feb 11, 2003

Apr 9, 2001

09/829353

John E. Richardson - Salt Lake City UT
Gregory C. Andrews - Sandy UT
Robert S. Miller - Sandy UT
Allen C. Campbell - Annabella UT

Varian Medical Systems, Inc. - Palo Alto CA

H01J 3510

378130, 378200, 378141

A cooling system for use with high-power x-ray tubes. The cooling system includes a dielectric coolant disposed in the x-ray tube housing so as to absorb heat dissipated by the stator and other electrical components, as well as absorbing some heat from the x-ray tube itself. The cooling system also includes a coolant circuit employing a pressurized water/glycol solution as a coolant. Pressurization of the water/glycol solution is achieved by way of an accumulator which, by pressurizing the coolant to a desired level, raises its boiling point and capacity to absorb heat. A coolant pump circulates the pressurized coolant through a fluid passageway defined in an aperture of the x-ray tube and through a target cooling block disposed proximate to the x-ray tube in the x-ray tube housing, so as to position the coolant to absorb some of the heat generated at the aperture by secondary electrons, and the heat generated in the target cooling block by the target anode of the x-ray tube. The target cooling block is in contact with the dielectric fluid so that some of the heat absorbed by the dielectric coolant is transferred to the coolant flowing through the target cooling block. The heated coolant is then passed through an air/water radiator where a flow of air serves to remove some heat from the coolant.

6002745, Dec 14, 1999

Jun 4, 1998

9/090765

Robert S. Miller - Sandy UT
Gregory Andrews - Sandy UT

Varian Medical Systems, Inc. - Palo Alto CA

H01J 3510

378128

A graphite-backed metallic x-ray tube target assembly has a rotary shaft which passes through the central opening of the annular graphite substrate and is secured to the metallic disk-shaped target. In order to protect the shaft from heat radiated from the graphite substrate, at least one tubular heat shield is brazed to the target and disposed between and separate from the inner wall of the annular graphite substrate and the outer peripheral surface of the shaft. For further protection, a tubular heat shielding member may be disposed inside the other heat shield, between the outer heat shield and the shaft. In order to minimize the heat conduction from the outer heat shield to the inner heat shielding member, they are mostly separated and attached to each other only along their bottom edges where they are tack-welded together at mutually separated positions such that the inner heat shielding member is supported entirely by the outer heat shield.

6115454, Sep 5, 2000

Aug 6, 1997

8/906701

Gregory C. Andrews - Sandy UT
Dennis H. Runnoe - Salt Lake City UT
John E. Richardson - Salt Lake City UT
James R. Boye - Salt Lake City UT

Varian Medical Systems, Inc. - Palo Alto CA

H01J 518

378140

An X-ray generation apparatus has a housing comprising an evacuated envelope with a rotatable anode target surrounded by an all metal grounded exterior structure and a cooling system. The cooling system comprises a coolant circulating system with heat exchanger and means for circulating a fluid coolant through an interior of the X-ray generating apparatus; a hollow shield structure with center aperture for passing and electron beam; and a cooling block which is disposed proximate to the rotatable anode target and comprises a disk with a plurality of concentric annular channels formed by concentric annular partitions. The shield structure and the disk of the cooling block are made of thermally conductive material. An interior of the shield structure is filled with structures such as pins, fins or pack bed which are made of thermally conductive materials. The fluid coolant is circulated through the shield structure, then into the plurality of channels of the cooling block and via an interior of the housing to the heat exchanger for efficient cooling of the X-ray generating apparatus.