Performance Positions on Demand
The PerfPoD™ concept provides a rigid, shake-free means for positive positioning of performance test assemblies. Alternative designs are offered for users who:
- test either Plate or Pipe, but not both, or
- do not need to change testing positions regularly.
It also can meet the needs of users who:
- test both Plate and Pipe, or
- change testing positions regularly, or
- test in the 5° or 15° code-permitted angular deviations, or
- test with backing, or
- test with an open root, or
- test with purge gas.
Fortunately, the PerfPoD™ uses a Modular Design that allows the user to start out with only the capabilities needed now. Additional capabilities can be added in the future, if needed.
The PerfPoD™ is available in four models to meet different user's space requirements and preferences:
- Wall Mount
- Floor Mount
- Free Standing
An example of each of these models is illustrated and described below. All four share the same inner square structural tube Post. The outer perforated tube of the sliding components, combined with a 3/8" steel self-locking pin, allows for adjustments of the working height of a Support Arm, in 1" increments, and of a table, if one is used.
There are two types of Support Arm. Both use self-locking pins to securely locate the sample Holding Fixtures.
- Basic Support Arm - See the Wall Mount configuration below
- Swivel Support Arm - See the Floor Mount model below
Each type of Support Arm also has stabilizers to remove any jiggle that might occur in the fixtures. They do not support any load and are only tightened finger tight.
(See Options in the Right Panel)
(See Applications in the Left Panel)
This is the base model. It is the best choice when space is limited, such as in small welding booths. The unit consists of:
- a Post ( 6, 7 or 8 feet tall)
- a Foot,
- a Side Wall Bracket, and
- a Basic Support Arm
The Side Wall Bracket is used when the booth is rectangular. The Bracket is mounted to the narrowest wall of the booth.
An optional Corner Wall Bracket utilizes the wasted space in the corner of a square or rectangular welding booth.
Pipe Fixture (Basic). If only pipe is to be tested, then the optional Basic Pipe Adapter and a Pipe Clamping Fixture can be used. Hover over the image to the left to see how these components are inserted into the Basic Support Arm. In this case, the Pipe Adapter and Clamping Fixture are oriented so that a 2" pipe is oriented in the 6G position. To change welding positions, the user first pulls the locking pin and loosens the stabilizer. He then withdraws the Pipe Adapter from the Arm and re-inserts it to give the desired orientation. The 5G and 2G positions are illustrated in the left panel.
An optional 2-6" Pipe Clamping Fixture allows for testing up to 6" schedule XXS pipe as well. For safety, the orientation of the Pipe Adapter should never be changed when a pipe larger than 2" nominal size is clamped in the fixture. It will be too unbalanced and unsafe to handle.
When you hover over the image above, you will also see the optional 16" wide table. The height of the table can be easily adjusted by pulling out the locking pin, raising or lowering the table, and re-inserting the pin.
An optional Basic Plate Fixture can be used to test plate. In addition, pipe can be tested by adding a Plate/Pipe attachment. In this image, a typical AWS D1.1 plate sample, consisting of two bevelled 3 x 7" plates and a 1 x 8" backing bar, are held in the 2G position by means of the adjustable (yellow) clamping jaws and eight screws.
Plate performance samples up to 1 inch thick can be tested using the standard length screws provided. By using optional or user-supplied longer screws, samples up to 1-1/2 inch thick can be tested. The four outer screws are first set to accommodate the thickness of the coupon and any spacers or backing bars that are required. For multiple tests of the same coupon set-up, these screws do not need to be re-adjusted. The four inner screws are then used for clamping. All of these fasteners are common medium strength socket head cap screws. The clamping screws are threaded into medium strength nuts. The nuts are captured on the backside of the fixture, so that no wrench is needed there, and so that they can be easily replaced if the threads wear out.
The jaws and the reinforced backing plate are designed to resist the longitudinal and transverse shrinkage forces created during welding of the sample. The coupons are solidly clamped, both in the front and the back along their entire length.
The Protractor Ring allows for easy repositioning of the plate sample to the 1G or 4G position. In addition, the user can take advantage of the 15° code-permitted angular deviations from the true flat or horizontal planes.
The 3G position is obtained by removing the locking pin and by removing and then re-inserting the Plate Fixture 90° clockwise to the left relative to the Manual Support Arm. This orientation is shown in the left panel.
The next image shows the same Plate Fixture with the addition of the optional Plate to Pipe Adapter and a 2-6" Pipe Clamping Fixture. The 6" schedule XXS pipe shown, is oriented in the 5G position. The 6G and 2G pipe positions can be achieved by pulling the pin on the protractor ring and pivoting the assembly upwards by either 45° or 90°, respectively. The user can also take advantage of the 15° code-permitted angular deviations for the 2G and 5G positions or the 5° deviations permitted for the 6G position.
For safety, the fixture should be reoriented prior to loading the plate or pipe sample. Also, the user must always be ready to support the entire weight of the fixture prior to pulling out the locking pin.
For testing with pipe, the Flexible Plate/Pipe Fixture does not require reorientation, left or right, relative to the Manual Support Arm, in order to achieve any of the Code pipe test positions. The 5G position is shown here and the 6G and 2G positions are shown to the left.
It is easier and safer to load either the Plate or the Pipe Fixture when it is at chest level of slightly below. Once loaded, one person, by himself, should not try to raise or lower the assembly shown in the previous two images. A second person should be enlisted to loosen the stabilizer and pull the locking pin when the lifter is confident that he has control of the entire weight. He can sense when he has control when the locking pin loosens. If he lifts too much, the second person still can't pull the pin because it will have been pushed against the top of the hole. The locking pin is re-inserted once the desired position is reached.
If re-setting the height of the Arm is to be done regularly, the addition of an optional winch is possible, either initially or later. The winch is described below.
The Plate/Pipe Fixture can also be used to fit up plate coupons prior to welding. To do so, the user first rotates the fixture to the 1G plate test position. The fixture now has a flat work surface. The coupons, spacers, and backing bars (as applicable) are inserted and lightly clamped. The root opening can be set by means of a user-supplied spacer bar of the correct width. The clamps are then tightened securely.
The sample is now ready to weld. No tack welds are needed. Just rotate the fixture into the correct position and begin the test.
There are several ways to set up an open root. We offer an optional one-piece, 1/2" thick Open Root Spacer that is inserted beneath the coupons and a non-contact, 1/8" thick, copper Spatter Guard to protect the fixture. The user can also use his own shop materials to accomplish this task if it is only needed occasionally. The spatter guard can be made of 1/8" steel, in this case.
If the open root set-up is needed regularly, or if a back purge gas is required, then we recommend our optional Open Root Backing Attachment. This assembly is inserted into the plate fixture prior to loading and clamping the coupons. All of the items mentioned here are shown toward the end of this page.
A common way to fit up pipe coupons is to use an appropriately sized channel laid on a bench with its legs turned upwards. A 2" x 1" channel works well for 2" and Super™ coupons. A 4-5" x 1-1/2" channel can be used for 6" coupons. When the coupons are laid into the channel, the edges of the legs align the OD's of the coupons.
Unfortunately, this method does not assure alignment of the coupon bores. According to ASME Specification SA-106, the outside diameter of 2" and 6" pipe can vary up to 1/16" and 3/32", respectively. For a 6" pipe with a 3/32" land, the mismatch at the root can be as much as the land itself. In addition, SA-106 only limits the wall thickness to a minimum value. The diameter of the bore can vary as much or more than the OD. This variation can be corrected by boring the pipe, which is common practice. However, the boring cannot correct the OD variation. If the boring machine is sloppy, in the sense that the pipe wobbles during machining, then the wall thickness can vary more than the limits mentioned above.
Also, it is difficult to add purging of the test joint, if needed, when it is in the horizontal position. Mixing of air with the argon occurs at the top of the joint, even though argon is heavier than air. The joint must be taped off. Both ends of the pipe assembly must also be taped off or plugged somehow. The effort required to reposition the assembly for each tack can become intensive and the results can be hard to control.
We offer an optional Pipe Tacking Clamp to aid in the fit-up of pipe coupons when using any of our Pipe Fixtures. It does not use the OD of the pipe for alignment. The user first rotates the fixture to the 2G pipe test position. The fixture now has a flat work surface as shown to the left. The base of the tacking clamp attaches to the clamping block on the Pipe Clamping Fixture. The tacking clamp is discussed further in a section below.
One pipe coupon is clamped into the Pipe Clamping Fixture. A solid welding wire with a diameter at least 1/32" larger than the desired root opening is bent into a 25 to 40° V-shape. The legs of the V should be long enough to bridge across the bevelled edge. The bevelled edge of the second coupon is placed onto the top of the wire. The Pipe Tacking Clamp is loosely tightened onto the top end of this assembly.
The inside of the joint is then viewed from the open end. The alignment of the bores is adjusted, by hand, in order to achieve a uniform fit-up. The Pipe Tacking Clamp is then tightened just enough to resist shifting of the joint while tacking.
A 3/8" tack is placed between the open ends of the V-wire. The Pipe Tacking Clamp is then loosened in order to remove the V-wire from the joint by using a screw driver or pliers to pry or pull the closed end of the wire. The Pipe Tacking Clamp can be used to adjust the root opening as needed. Allowance should be made for shrinkage of the root opening that will occur when additional tacks are added. It is not advisable to place spacers in the root opening at this point, because they will be very difficult to remove after more tacking.
For users who desire complete maneuverability, the Swivel Support Arm provides it, and gives the PerfPoD™ its name: "PERFormance Positions On Demand". This configuration comes complete with a Plate Fixture. The two components are joined by a bearing assembly that allows the Plate Fixture to swivel about its horizontal support axis. It has four possible orientations: 0°, -15°, +15°, and +90°. The image to the left shows the fixture oriented at 0°. To select another orientation, the user disengages the locator pin by means of the large four-lobe handle, and rotates the fixture as desired.
The image shows a typical 3/8" AWS D1.1 plate sample, with the fixture oriented at 0°. This places the sample in the 2G welding position. While oriented this way, the 1G and 4G positions can then also be selected by means of the Protractor Ring. Or, if the fixture is swivelled counterclockwise by 90°, as shown in the left panel, the sample is rotated to the 3G position.
An optional Winch Kit is offered to make the vertical adjustment of the fixtures more convenient and doable by one person. It can be added to either Support Arm. The kit consists of a winch, a pulley assembly and attachment hardware. The winch is attached to the Support Arm and the pulley assembly is attached to the top of the Post. Steel wire rope does the lifting and lowering. The winch is shown attached to the Swivel Support Arm above. Except for the attachment points, the attachment of the winch to the Manual Support Arm is similar.
The winch requires a minimum cable load of 50 lb., in order for it to work properly when lowering the Support Arm and any attachments. The user can add a counterweight to the Support Arm if needed to meet this minimum.
This is a step up from the Wall Mount Base Model because it allows more access from all sides and can be mounted anywhere on a 4" thick concrete floor. It is shown here with the Swivel Mounting Arm and 6" Pipe Fixture, but any of the options described above can be used, as well.
The post must be anchored to the floor prior to installation of the Mounting Arm. It can be mounted as close as 17" to an adjacent wall.
An optional 32" wide Table can be used with this model. The height of the table can be adjusted by 1" increments and locked in place.
By the addition of an optional Front Leg, the Floor Mount Model can be converted into a Free Standing Model. This allows the PerfPoD™ to be located anywhere without attachment to the floor. A single front leveling screw is used to compensate for unevenness of the floor.
This model is just as sturdy and rigid as the floor mounted model. It will not tip over if configured in any of the ways shown above. Obviously, care must be exercised to be sure that outside influences, for example, forklift forks or crane hooks, do not contact any part of the PerfPoD™ above its base. An exception would be if the PerfPoD™ needs to be moved. It can be slid around if the leveling screw and attached pad are raised off of the floor. A forklift can be used to move it over longer distances. In this case, two feet must be on each fork, and some means must be provided to assure that the feet won't slide off the forks.
The Free Standing Model can be made completely mobile by adding optional casters as shown here. These special leveling casters allow the PerfPoD™ to be moved without any man-handling or lifting equipment. There is a notched wheel (see in right column above) that allows each leveling pad to be raised or lowered. For normal use, each pad is lowered so that the casters do not touch the floor. To move, or re-position the PerfPoD™, each pad is raised so that all four casters support it.
This fixture is used with either version of the Plate Fixture. It is inserted into the Plate Fixture as if it were a coupon set. The two knurled head screws locate the fixture and assure that it won't fall out if the Plate Fixture is turned while nothing is clamped in it. The coupons to be welded are inserted in front of the fixture, centered and positioned to provide the desired root opening. They are then clamped in the normal way which also securely clamps the fixture.
The basic version of this fixture has a Non-contact, Copper Chill Bar as shown in the right column. This version is used for welding processes like SMAW, GMAW, and FCAW, when they are used to weld materials that do not require a backing purge gas. The purpose of the 1/8" thick copper chill bar is to protect the inside of the fixture from spatter and wire burn-throughs. The chill bar is removable so that it can be cleaned up after repeated use. It can also be replaced when it is worn beyond repair.
An optional copper Purge Insert is available for use with the GTAW process. It consists of two copper side bars that are attached to a backing. This assembly is inserted in place of the chill bar and fastened with four screws. A separate purge tube and gas fitting is then inserted into holes provided in the fixture. A separate cap block is then attached with two screws to locate the parts and to protect the gas fitting.
Special chill bars that are intended to contain the weld metal on the root side of the joint can be be provided. We would need the details of the desired root shape in order to design them and to provide a quote.
This clamp is used to aid in the fit-up of pipe coupons as discussed in a section above. It is easily attached to either of the 2" or 6" Pipe Clamping Fixtures by means of a simple latch. It is adjustable for pipe assemblies from 6 to 8-1/2 inches long. After tacking is complete, the clamp can be quickly removed by releasing the latch.
The 2" version of the clamp is shown to the left. It is applicable to all schedules of 2" pipe as well as to SUPER COUPONS™. The 2-6" version is applicable to all schedules of pipe from 2" to 6" nominal pipe size. The 2" version can be converted to the 2-6" version later, if the need arises, by adding three additional parts.
If purging is needed, a gas line can be attached to the fitting on the bottom of the Pipe Clamping Fixture. Since argon is heavier than air, it will push the air upward. The argon rises in the lower coupon and flows evenly out of the root opening. To reduce the amount of backing gas being used, especially for large diameter pipe, a weld purging tape can be partially wrapped around the joint, exposing only that portion that will be tacked. The tape can be repositioned in order to make additional tacks. Also, light gauge, sheet metal half-discs can be placed on either side of the tacking clamp jaw.
Purge caps are available for 2" and 6" nominal pipe size coupons and for 2-3/4" OD Super Coupons™. These include a purging valve and a handle or handles. The purging valve is used to initiate and control the gas flow. These caps can be used alone or with weld purging tape at the joint.
When the purge gas is first turned on at the tank, the purging valve can be opened to allow the escape of trapped air. A flow of 5-10 cfh at the tank is usually sufficient. By using the purging valve the welder can further control the flow at the joint. Too little flow will allow oxidation of the weld metal. Too much flow can affect the internal bead contour. As the weld nears completion, the welder will need to open the purging valve more in order to decrease flow at the joint.
The handles are provided to aid in removal of the caps. If the welder or an inspector wants to view the inside of the root pass, he can remove the cap. Unfortunately, the purge and excess gas will be lost during the inspection. The purge will need to be re-established again when the cap is replaced. The next section describes an alternative cap that allows inspection at any time without losing the purge.
If it is desired to view the root pass regularly, these caps offer the best solution. A port hole with a crystal clear 2" diameter sight glass offers a 360° view of the root at any time. An inspector or trainer can even watch while the welding is in progress. The gas purge is maintained without interruption.
Purge Sight Glass Caps are available for 2" and 6" nominal pipe size coupons and for 2-3/4" OD Super Coupons™. They include a purging valve and a handle or handles. They have the same functions as discussed above for the plain Purge Caps. These caps can be used alone or with weld purging tape at the joint.
Note: Specifications subject to change without notice.