Patent Description:
Many pressure vessels require the use of pressure switches, ports, and other devices to fill, monitor, and functionally use the pressure vessel. These devices need to be easily removed for replacement when they malfunction, are damaged, or during refurbishment of the pressure vessel. The fittings that hold these devices are welded into the pressure vessel. The fittings have internal threads that are used to receive the mating threads on the devices to be installed. The threaded connection does not create an airtight seal; therefore, a sealing flange is used on both the fitting and the device. After the two sealing flanges are in contact, a weld is used to seal the edges of the flanges together to form an airtight seal.

When the situation arises in which the device must be removed from the pressure vessel, the weld around the two sealing flanges is removed and the device is unthreaded from the fitting. Use of a grinder or specialized hand tool can result in too much material being removed from the flange on the fitting. If too much material is removed, the flange on the fitting could become too small to be utilized again. Using the specialized hand tool is time consuming because the operator must adjust the depth of the cutting/grinding edges, install on the flange, rotate a few times to perform grinding, and then remove the specialized hand tool to visually determine how much material was removed. The technician repeats the process until the correct amount of material has been removed. As such, there is a need for a flange removal tool that consistently removes a weld and a flange of a device installed on a pressure vessel in a time-efficient manner.

<CIT> discloses a sawing and turning device. Document <CIT> shows a method for removing tubes from a fire tube or a water tube boiler using a drill press equipped with an annular rotary cutting tool and a cylindrical pilot received within the annulus of the cutting tool. The drill rig is secured directly to the boiler by registering the bottom plate with two or more of the boiler tube openings.

According to one aspect of the invention, there is provided a flange removal tool assembly as claimed in claim <NUM>.

According to another aspect of the invention, there is provided a method of removing a weld and a flange of a device, with the device secured to a fitting on a pressure vessel as claimed in claim <NUM>.

<FIG> is an exploded cross-sectional view of device <NUM> and fitting <NUM>. <FIG> is a cross-sectional view of device <NUM> and fitting <NUM> installed in pressure vessel <NUM>. <FIG> is a cross-sectional view of annular cutting tool <NUM> positioned over device <NUM> and fitting <NUM>. <FIG> will be discussed together. Device <NUM> includes body <NUM>, flange <NUM>, and external threads <NUM>. Flange <NUM> includes sealing surface <NUM> and edge <NUM>. Fitting <NUM> includes flange <NUM>, internal threads <NUM>, base <NUM>, and neck <NUM>. Flange <NUM> includes sealing surface <NUM> and edge <NUM>. Annular cutting tool <NUM> includes hollow section <NUM> and cutting tip <NUM>. <FIG> also show first weld <NUM> and second weld <NUM>.

Flange <NUM> is circular in shape and surrounds the body <NUM> of device <NUM>. Sealing surface <NUM> is disposed on the bottom side of flange <NUM> and is configured to provide a flat mating surface for sealing surface <NUM> of fitting <NUM>. Edge <NUM> is positioned at the intersection of the side surface of flange <NUM> and the circumferentially outermost point of sealing surface <NUM>. External threads <NUM> are situated on body <NUM> below flange <NUM>, sealing surface <NUM>, and edge <NUM>. External threads <NUM> are configured to be threaded into internal threads <NUM>, securing device <NUM> in fitting <NUM>. Device <NUM> can be a port, sensor, pressure switch, or any other device that is required to fill, monitor, or functionally use pressure vessel <NUM>. Pressure vessel <NUM> can be any vessel that is suitable for storing a fluid at an elevated pressure compared to ambient pressure. Pressure vessel <NUM> can be of any suitable shape or size and is not limited to the specific embodiment presented in the following discussion.

Flange <NUM> constitutes the top portion of fitting <NUM> and includes sealing surface <NUM> on the top surface of flange <NUM>. Sealing surface <NUM> is configured to provide a flat mating surface for flange <NUM> of device <NUM>. Edge <NUM> is positioned at the intersection of the side surface of flange <NUM> and the circumferentially outermost point of sealing surface <NUM>. Internal threads <NUM> are located in the center portion of fitting <NUM> and are configured to receive external threads <NUM> of device <NUM>. Base <NUM> is positioned opposite flange <NUM> and constitutes the bottom portion of fitting <NUM>. Base <NUM> is configured to be welded into pressure vessel <NUM>. Neck <NUM> is disposed between flange <NUM> and base <NUM> and constitutes the smaller-diameter portion of fitting <NUM>.

Hollow section <NUM> is disposed in the center portion of annular cutting tool <NUM>. Hollow section <NUM> is configured to receive body <NUM> of device <NUM>, allowing cutting tip <NUM> to reach flange <NUM> of device <NUM>. Cutting tip <NUM> is disposed at the bottom edge of annular cutting tool <NUM> and is configured to remove material in a level and consistent manner across cutting tip <NUM>. A level and consistent cut ensures that a precise amount of material is removed from flange <NUM> of device <NUM> and not from flange <NUM> of fitting <NUM>. Cutting tip <NUM> is at an angle of <NUM> degrees measured from axis A-A to achieve a level and consistent cut.

As shown in <FIG>, fitting <NUM> is positioned within an aperture in pressure vessel <NUM> and securely held in place with first weld <NUM>. First weld <NUM> is disposed at the location where base <NUM> and pressure vessel <NUM> are in contact. First weld <NUM> circumferentially surrounds and attaches fitting <NUM> to pressure vessel <NUM>, creating an airtight seal between fitting <NUM> and pressure vessel <NUM>. Fitting <NUM> includes internal threads <NUM>, which are configured to receive external threads <NUM> of device <NUM>. Device <NUM> is installed onto pressure vessel <NUM> by threading device <NUM> into fitting <NUM>. Once device <NUM> has been fully threaded into fitting <NUM>, flange <NUM> of device <NUM> and flange <NUM> of fitting <NUM> are in contact. Further, sealing surface <NUM> of device <NUM> and sealing surface <NUM> of fitting <NUM> are in contact. Second weld <NUM> circumferentially surrounds the location where edge <NUM> of device <NUM> and edge <NUM> of fitting <NUM> are in contact, creating an airtight seal between device <NUM> and fitting <NUM>.

After device <NUM> and fitting <NUM> are fully installed, device <NUM> may need to be removed from pressure vessel <NUM> for various reasons. For example, device <NUM> may need to be removed for replacement due to damage or if device <NUM> malfunctions. Further, device <NUM> may need to be removed when it is time to refurbish pressure vessel <NUM>. To remove device <NUM> from fitting <NUM>, flange <NUM> of device <NUM> and second weld <NUM> are removed and then device <NUM> can be unthreaded from fitting <NUM>. A cutting or grinding process is used to remove flange <NUM> of device <NUM> and second weld <NUM> from fitting <NUM>. When the cutting or grinding process is performed, it is important that only minimal amounts of material, if any, be removed from flange <NUM> of fitting <NUM>. If too much material is removed from flange <NUM>, flange <NUM> could become too small to be utilized again. For example, if the diameter of flange <NUM> of device <NUM> is larger than the diameter of flange <NUM> of fitting <NUM>, edge <NUM> and edge <NUM> may not align correctly and second weld <NUM> will not create an airtight seal. Further, if too much material is removed from flange <NUM> of fitting <NUM>, flange <NUM> can become too thin to receive second weld <NUM>. Thus, only a minimal amount of material should be removed from flange <NUM> of fitting <NUM>.

As shown in <FIG>, annular cutting tool <NUM> is used to perform the cutting or grinding process to remove flange <NUM> of device <NUM> and second weld <NUM>. Annular cutting tool <NUM> is lowered toward device <NUM> and fitting <NUM>. Hollow section <NUM> receives body <NUM> of device <NUM>, allowing contact to occur between flange <NUM> and cutting tip <NUM> and between cutting tip <NUM> and second weld <NUM>. Annular cutting tool <NUM> is rotated and the flat surface of cutting tip <NUM> grinds a consistent amount of material off of flange <NUM> of device <NUM>. Annular cutting tool <NUM> grinds flange <NUM> to fully remove flange <NUM> and the portion of second weld <NUM> associated with flange <NUM>, which connects device <NUM> to fitting <NUM>. The angle of cutting tip <NUM> prevents annular cutting tool <NUM> from grinding flange <NUM> of fitting <NUM>, thereby preserving flange <NUM>. With flange <NUM> of device <NUM> removed, device <NUM> is no longer attached to fitting <NUM> and can be unthreaded. Annular cutting tool <NUM> can then be raised away from device <NUM> and fitting <NUM>, allowing device <NUM> to be unthreaded from fitting <NUM>. Annular cutting tool <NUM> provides significant advantages because it produces consistent and accurate grinding, resulting in flange <NUM> and second weld <NUM> being removed while minimizing or eliminating removal of material from flange <NUM> of fitting <NUM>.

<FIG> is an isometric view of flange removal tool assembly (FRTA) <NUM>. <FIG> is an isometric view of FRTA <NUM> with pressure vessel <NUM> mounted on the assembly. <FIG> is an enlarged view of detail Z of <FIG>. <FIG> is a top view of vise <NUM> engaging neck <NUM> of fitting <NUM>. <FIG> will be discussed together. FRTA <NUM> includes annular cutting tool <NUM>, cutting tool actuator <NUM>, vise <NUM>, and fixture <NUM>. Cutting tool actuator <NUM> includes housing <NUM>, motor <NUM>, lever <NUM>, and spindle <NUM>. Vise <NUM> includes main body <NUM>, moving jaw <NUM>, and stationary jaw <NUM>. Moving jaw <NUM> includes flat tip <NUM> and stationary jaw <NUM> includes concave tip <NUM>. Fixture <NUM> includes center support <NUM>, crank <NUM>, first set of support members <NUM>, second set of support members <NUM>, and flat tabletop surface <NUM>.

Cutting tool actuator <NUM> is positioned atop FRTA <NUM> and is supported by fixture <NUM>. Housing <NUM> covers the gearing and other components that allow cutting tool actuator <NUM> to operate. The base of housing <NUM> is mounted to fixture <NUM> with fasteners suitable to withstand normal forces experienced during operation, fixedly securing cutting tool actuator <NUM> in place. Motor <NUM> is positioned on top of and secured to housing <NUM>. Motor <NUM> provides mechanical energy to cutting tool actuator <NUM>, allowing cutting tool actuator <NUM> to function. Motor <NUM> is a low revolution per minute (RPM) motor configured to prevent heat buildup during the removal process. Located near the front and bottom portion of housing <NUM> is spindle <NUM>. Spindle <NUM> is a rod that extends and is attached within housing <NUM>. When cutting tool actuator <NUM> is operational, spindle <NUM> rotates about axis A-A at a speed designated by the controls on cutting tool actuator <NUM>. Removably connected to spindle <NUM> is annular cutting tool <NUM>. When annular cutting tool <NUM> is connected to spindle <NUM>, annular cutting tool <NUM> rotates about axis A-A at the same rate as spindle <NUM>. Attached to the side of housing <NUM> is lever <NUM>. Lever <NUM> is also attached to spindle <NUM> within housing <NUM>. Lever <NUM> pivots about an axis and controls the vertical height of spindle <NUM>. For example, when lever <NUM> is rotated downward, spindle <NUM> will translate vertically downward along axis A-A at a proportional rate. Likewise, when lever <NUM> is rotated upward, spindle <NUM> will translate vertically upward along axis A-A at a proportional rate. Cutting tool actuator <NUM> provides rotating power to annular cutting tool <NUM> to facilitate removal of flange <NUM> of device <NUM> and second weld <NUM>.

Vise <NUM> is positioned below cutting tool actuator <NUM> and is supported by fixture <NUM>. Vise <NUM> is secured to fixture <NUM> using fasteners that are suitable to withstand normal forces experienced during operation. Vise <NUM> is used to firmly hold an object in place while work is being done on the object. In the embodiment shown, vise <NUM> includes main body <NUM>, moving jaw <NUM>, and stationary jaw <NUM>. Main body <NUM> surrounds and protects the internal components of vise <NUM> from being damaged or filled with debris. Moving jaw <NUM> is coupled to the internal components within main body <NUM> and is configured to translate horizontally to apply pressure to an object that is placed between moving jaw <NUM> and stationary jaw <NUM>, such as neck <NUM> of fitting <NUM>. Moving jaw <NUM> includes flat tip <NUM> that is configured to press against neck <NUM> of fitting <NUM>. Stationary jaw <NUM> is coupled to fixture <NUM> and includes concave tip <NUM> that is configured to extend around neck <NUM> of fitting <NUM>. Further, concave tip <NUM> of stationary jaw <NUM> is configured to axially align fitting <NUM> on axis A-A, ensuring precise alignment during operation of FRTA <NUM>. As shown, vise <NUM> is a pneumatic vise. It is understood, however, that vise <NUM> can be a hand-operated vise or a powered vise.

As shown in <FIG>, fitting <NUM> of pressure vessel <NUM> is inserted into concave tip <NUM> of stationary jaw <NUM>. More specifically, neck <NUM> of fitting <NUM> interfaces with concave tip <NUM> of stationary jaw <NUM>, aligning fitting <NUM> on axis A-A. Moving jaw <NUM> is then translated horizontally toward stationary jaw <NUM>. Flat tip <NUM> of moving jaw <NUM> applies pressure to neck <NUM> of fitting <NUM>, opposite stationary jaw <NUM>. Moving jaw <NUM> and stationary jaw <NUM> hold fitting <NUM> securely while FRTA <NUM> is operational and work is being done on pressure vessel <NUM>.

Fixture <NUM> is positioned at the base of FRTA <NUM> and provides support for all the other components of FRTA <NUM>. Fixture <NUM> includes center support <NUM>, crank <NUM>, first set of support members <NUM>, second set of support members <NUM>, and flat tabletop surface <NUM>. Center support <NUM> is positioned proximate the center of flat tabletop surface <NUM> and is axially aligned with axis A-A. Center support <NUM> is configured to provide support to pressure vessel <NUM> and also to translate in the vertical direction. Crank <NUM> is operably connected to center support <NUM>; therefore, to translate center support <NUM> in the vertical direction, crank <NUM> is rotated. In the embodiment shown, crank <NUM> is a hand-operated crank, but it is understood that crank <NUM> can be a powered crank. First set of support members <NUM> are situated at the bottom portion of fixture <NUM> and are configured to provide structural support for all the components of FRTA <NUM>. Second set of support members <NUM> are situated at the top portion of fixture <NUM> and are configured to provide structural support to cutting tool actuator <NUM> and vise <NUM>. First set of support members <NUM> and second set of support members <NUM> are comprised of a plurality of horizontal and vertical tubes that are welded together to form a support structure. Flat tabletop surface <NUM> is positioned proximate the middle of fixture <NUM>. Flat tabletop surface <NUM> is secured to first set of support members <NUM> using fasteners or in any other desired manner. Flat tabletop surface <NUM> can be utilized as a working surface when FRTA <NUM> is being operated.

During operation, fitting <NUM> of pressure vessel <NUM> is first inserted into stationary jaw <NUM>. Moving jaw <NUM> is translated horizontally toward stationary jaw <NUM> until moving jaw <NUM> applies pressure to neck <NUM> of fitting <NUM>. Stationary jaw <NUM> and moving jaw <NUM> firmly grasp neck <NUM> of fitting <NUM>, resulting in a hanging pressure vessel <NUM>. Center support <NUM> is raised vertically toward the hanging pressure vessel <NUM> using crank <NUM>. Center support <NUM> is raised until center support <NUM> contacts the underside of pressure vessel <NUM>, providing support to pressure vessel <NUM> during operation of FRTA <NUM>.

Using lever <NUM>, a non-rotating spindle <NUM> and attached annular cutting tool <NUM> are lowered vertically toward device <NUM> and fitting <NUM>. Spindle <NUM> and annular cutting tool <NUM> are lowed vertically until cutting tip <NUM> of annular cutting tool <NUM> contacts flange <NUM> of device <NUM>. Using the controls on cutting tool actuator <NUM>, cutting tool actuator <NUM> marks the vertical location of spindle <NUM>, indicating the displacement necessary to contact the top of flange <NUM> of device <NUM>. For example, cutting tool actuator <NUM> can mark the vertical displacement using a digital caliper or similar apparatus. Next, motor <NUM> is activated and the rotating spindle <NUM> and annular cutting tool <NUM> are lowed toward device <NUM> and fitting <NUM> until cutting tool actuator <NUM> reaches the marked location, indicating cutting tip <NUM> is contacting the top surface of flange <NUM> of device <NUM>. The approximate thickness of flange <NUM> of device <NUM> is known; therefore, the operator knows how much vertical translation beyond the marked location is necessary to remove only flange <NUM> of device <NUM>. Spindle <NUM> and annular cutting tool <NUM> continue to be lowered until the approximate thickness of flange <NUM> has been removed.

FRTA <NUM> allows the operator to precisely remove flange <NUM> of device <NUM> and second weld <NUM> while at the same time minimizing the amount of material removed from flange <NUM> of fitting <NUM>. Ideally, cutting tip <NUM> will remove material only from flange <NUM> and second weld <NUM> to free device <NUM> from fitting <NUM>. It is desired to remove minimal amounts of material from flange <NUM> of fitting <NUM> because if too much material is removed from fitting <NUM>, fitting <NUM> may no longer be useable. Once flange <NUM> of device <NUM> and second weld <NUM> have been removed, annular cutting tool <NUM> is raised vertically away from device <NUM> and fitting <NUM>. Device <NUM> can then be unthreaded and removed from fitting <NUM>. After device <NUM> has been removed, flange <NUM> of fitting <NUM> can be cleaned up and made suitable to receive a new device <NUM> that is to be inserted.

FRTA <NUM> allows device <NUM> to be easily replaced while also preventing damage to fitting <NUM> located on pressure vessel <NUM>. FRTA <NUM> enables the operator to quickly inspect second weld <NUM> during the removal process and consistently remove the desired amount of material in a time-efficient manner. FRTA <NUM> facilitates removal of flange <NUM> of device <NUM> and second weld <NUM> while minimizing contact with flange <NUM> of fitting <NUM>, ensuring flange <NUM> of fitting <NUM> can be reused.

<FIG> is a flowchart of method <NUM> of removing a flange of a device and a weld from a fitting when the device and the fitting are secured to a pressure vessel, without removing a flange of the fitting. For example, method <NUM> could be used to remove flange <NUM> of device <NUM> and second weld <NUM> from fitting <NUM> (best seen in <FIG>) when device <NUM> and fitting <NUM> are secured to pressure vessel <NUM> (best seen in <FIG>), without removing flange <NUM> of fitting <NUM> (best seen in <FIG>). Method <NUM> includes steps <NUM>-<NUM>.

In step <NUM>, the pressure vessel is secured to a flange removal tool assembly (FRTA), such as FRTA <NUM> (shown in <FIG>). In some examples, the pressure vessel is secured to the FRTA by inserting a neck of the fitting, such as neck <NUM> of fitting <NUM> (best seen in <FIG>), into a concave portion of a stationary jaw, such as concave tip <NUM> of stationary jaw <NUM> (shown in <FIG>). Then a flat tip of a moving jaw, such as flat tip <NUM> of moving jaw <NUM> (shown in <FIG>), applies pressure to the opposite side of the neck of the fitting, firmly grasping the neck to hold the pressure vessel stationary during operation of the FRTA. Finally, a center support of a fixture, such as center support <NUM> of fixture <NUM> (shown in <FIG>), is raised until the center support contacts a bottom surface of the pressure vessel to provide support during operation of the FRTA.

In step <NUM>, an annular cutting tool, such as annular cutting tool <NUM> (shown in <FIG>), is lowered with a lever, such as lever <NUM> (shown in <FIG>), onto a top surface of the flange of the device connected to the fitting on the pressure vessel. In step <NUM>, a cutting tool actuator, such as cutting tool actuator <NUM> (shown in <FIG>), records the location of the top surface of the flange of the device. For example, the cutting tool actuator can record the vertical displacement of a spindle, such as spindle <NUM> (shown in <FIG>), using a digital caliper or similar apparatus to record the location of the top surface of the flange of the device. In step <NUM>, the cutting tool actuator is activated to rotate the annular cutting tool attached to the spindle. In step <NUM>, the rotating annular cutting tool is lowered with the lever to remove the weld and the flange of the device without removing the flange of the fitting. For example, the annular cutting tool is lowered to the location recorded in step <NUM>, then lowered a distance associated with the thickness of the flange of the device. By lowering only that associated distance, it ensures that the flange of the device is removed without damaging the flange of the fitting.

Method <NUM> is an example of using the FRTA to consistently remove a weld and a flange of a device in a time-efficient manner, while at the same time minimizing damage to a flange of a fitting installed on a pressure vessel.

There is provided a method of removing a weld and a flange of a device, as claimed in claim <NUM>.

The center support may be operably connected to a crank. The crank may be configured to adjust a vertical location of the pressure vessel.

The flange of the fitting may circumferentially extend around the top of the fitting and may be configured to receive the weld around an edge of the flange to secure the device to the fitting.

Claim 1:
A flange removal tool assembly (<NUM>) for removing a flange of a device coupled to a neck of a fitting of a pressure vessel, the flange removal tool assembly (<NUM>) comprising:
a cutting tool actuator (<NUM>) that includes a housing (<NUM>), a motor (<NUM>), a lever (<NUM>), and a spindle (<NUM>), wherein the lever (<NUM>) is disposed on the housing (<NUM>) and interfaces with the spindle (<NUM>) that extends from the housing (<NUM>);
an annular cutting tool (<NUM>) secured to the spindle (<NUM>), the annular cutting tool comprising a cutting tip disposed about a hollow center portion at an angle of <NUM> degrees relative to an axis of rotation of the spindle (<NUM>), wherein:
the hollow center is configured to receive a body of the device such that the annular cutting tool is disposed circumferentially around the flange of the device, thereby allowing contact to occur between the flange of the device and the cutting tip; and
the cutting tip is configured to remove material from the flange of the device;
a vise (<NUM>) disposed below the cutting tool actuator (<NUM>), the vise (<NUM>) comprising a stationary jaw and a moving jaw that translates relative to the stationary jaw, wherein the vise is configured to grip the neck (<NUM>) of the fitting (<NUM>) located on the pressure vessel (<NUM>); and
a fixture (<NUM>) disposed below the vise (<NUM>), wherein the fixture (<NUM>) includes a center support (<NUM>) axially aligned with an axis of rotation of the spindle (<NUM>), the center support (<NUM>) configured to support the pressure vessel (<NUM>);
wherein the annular cutting tool (<NUM>) is configured to remove the flange (<NUM>) of the device (<NUM>) installed in the fitting (<NUM>) located on the pressure vessel (<NUM>).