COSASCO TWO-INCH SYSTEM
INSTALLATION, OPERATION & MAINTENANCE
MANUAL
HOT TAP
Rohrback Cosasco Systems
11841 East Smith Ave.
Santa Fe Springs, CA 90670
Tel: (1) 562-949-0123
Fax: (1) 562-949-3065
E-mail: rcs@rohrbackcosasco.com
Web Site: http://www.rohrbackcosasco.com
P/N: 740078 rev. -
Table of Contents
Chapter 1 Introduction….............................................................1
Chapter 2 Hydrostatic Testing………………………………….....2
Chapter 3 Operating Instructions …..........................................5
Chapter 4 Disassembly-Assembly (Hot Tap)…………………...9
Chapter 5 Care & Maintenance……………………………….….13
1
Chapter 1
Introduction
The Cosasco 2” Hot Tap was developed to provide a means of adding a Cosasco Access System
to any pipeline or vessel already on stream – without shutdown or product loss. The Hot Tap is
used in conjunction with any of the Cosasco Retrievers and Service Valves to enable both
retrieval and installation under pressure. The Hot Tap Assembly has ample cutter travel to allow
hot tapping through all standard access fitting lengths, and pipe wall thicknesses. The Hot Tap is
conveniently packaged in a Kit which contains both spare parts and special tools.
The Hot Tap cutter will trepan a hole that will allow free passage of any of the Cosasco probes
and tools. The cutter will also retain the slug and minimize the chips dropped into the line. Two
different tooth designs are provided in the Hot Tap Kit to cover both thin and heavy wall
thicknesses. The Hot Tap Ball End Mill and Square Nose End Mill were developed to allow
repair of undersized or obstructed pre-cut holes in order to obtain concentricity of the access
fitting body bore and the trepanned hole.
The 2” Hot Tap will operate in any position, and cut any grade of pipe or vessel wall. Operating
range is 0 to 3600 psig (- to 253 kg/sq cm) at temperatures from –20 to +200°F (-29 to +93°C).
The cutter can be driven manually with a ratchet type wrench, or with motorized power. The
cutter feed is regulated manually with a feed screw and handle assembly, to provide reliable and
variable cutter feed.
2
Chapter 2
Hydrostatic Testing
(Refer to Figure 1)
The Hydrostatic Test Assembly #121328 was developed to provide a means to test the access
fitting weld integrity prior to hot tapping. It is constructed to allow its use on top-of-line, bottomof-line, and also horizontally mounted access fittings.
A. Top-of-line Access Fittings:
1. Clean the outside of the Access Fitting weld of any weld slag, grease, dirt, etc.
2. Assemble the test plug (1) with the gauge tee (12) in the top center port, and snap the
connector (8) in the side port (as shown in Figure 2). Either tube (2) or (3) can be used or
removed.
3. Pour an appropriate test media; water for ambient temperature, and kerosene or other approved
fluid for sub-zero, into the Access Fitting, filling it to the base of the threads.
4. Grease the test plug (1) thread and o-ring (7). Install the female half of the snap connector (9)
with the hose removed. Close the bleed valve (15).
5. Begin to thread the test plug (1) into the fitting. When fluid begins to come out of the snap
connector (9), remove the female half (sealing the port).
6. Open the bleed valve (15) slightly and continue turning to expel the remainder of the air.
7. When the o-ring (7) is felt to engage Access Fitting bore, and all air has escaped, close the
bleed valve (15).
8. Turn the test plug (1) with a wrench to produce a pressure of 1-1/2 times the line pressure.
Should the plug run out of travel before reaching the required pressure, air is trapped in the
fitting.
9. Dry the outside of the weld, and watch for a pressure drop or leaks. The pressure should hold
constant for a minimum of three minutes.
B. Bottom-of-line Access Fittings:
1. Clean the outside of the Access Fitting weld slag, grease, dirt, etc.
2. Assemble the test plug (1) with the gauge tee (12) in the top center port and the snap connector
(9) in the side port (as shown in Figure 2). The short tube (4-1/8”, #121315) (2) should be used
Chapter 2
3
for 5.25” or 6.25” height Access Fittings. The long tube (3) (5-1/8”, #121316) should be used for
longer fittings.
3. Grease the test plug (1) thread and o-ring (7). Screw the plug (1) into the Access Fitting until
the o-ring (7) contacts the bore.
4. Open the bleed valve (15) slightly. Connect the female snap connector (9) and hose (1) to the
side.
5. Fill the squeeze bottle (11) with water, kerosene, or other suitable fluid.
6. Hold the hose above the Access Fitting level and force the fluid into the Access Fitting. Close
the bleed valve (15) when all of the air has escaped.
7. Remove the female snap connector (9) while the hose (10) still contains liquid.
8. Refer to Section A, steps 8 and 9, and continue as indicated.
C. Horizontal Access Fittings:
1. Clean the outside of the Access Fitting weld of any weld of any weld slag, grease, dirt, etc.
2. Assemble the test plug (1) with the gauge tee (12) in the side port, and with snap connectors (8
and 9) in the top center port (opposite to what is shown in Figure 2). Either tube (2 or 3) can be
used or removed.
3. Grease the test plug (1) thread and o-ring (7). Screw the plug (1) into the Access Fitting until
the o-ring (7) contacts the Access Fitting body bore, leaving the bleed valve (15) pointing
upwards or in a vertical position.
4. Refer to Section B, steps 4 through 8 and continue as indicated.
4
Hydrostatic Testing
Figure 1
PARTS LIST: 2” Hydrostatic Test Assembly #121328 (See Fig. 1); component assembly of 2” Hot Tap Kit
#126248
Item
Quantity
Description
Part No.
1
1 each
2” Hydrostatic Plug
121215
2
1 each
Hydrostatic Tube, 4.125
121315
3
1 each
Hydrostatic Tube, 5.125
121316
4
2 each
Spring Pin (31-S-062-0312)
129101
5
3 each
Spring, .034 wire x 1-1/2” H.D.
129102
6
2 each (1)
O-ring 568-010 Nitrile
124729
7
2 each (1)
O-ring 568-220 Nitrile
110672
8
1 each
Quick Couple, 1/4”
129103
9
1 each
Quick Couple, 1/4”
129104
10
1 each
Hose, 1/4 ID x 4 ft., Neoprene
129105
11
1 each
Bottle, 8 oz. Polyethylene
129106
12
1 each
Street Tee, 1/4”
129107
13
1 each
Pressure Gauge, 5000 PSI
129014
14
1 each
Reducing Bushing, 1/4 to 1/8
129108
15
1 each
Bleeder Valve
124168
NOTE: Quantity in parenthesis is the number of spares supplied
5
Chapter 3
Operating Instructions
(Refer to Figure 2)
The operators of the Hot Tap shall verify that the line pressure and fluid are acceptable for hot
tapping. The Access Fitting location shall be checked to insure adequate clearance for the
Retriever and Service Valve hook-up to be used.
1. Determine if the Hot Tap will have adequate cutter travel. The 2” Hot Tap has maximum
cutter travel of 3-3/8” or (8.57 cm).
Required cutter travel is determined by the Access Fitting length and the pipe wall thickness. To
calculate the required minimum cutter travel:
Minimum cutter travel = A+PW – 5”
A
= Access Fitting body length
PW = Pipe wall thickness
Generally the Hot Tap will cut all pipe wall thicknesses when used with 5.25, 6.25, or 7.25”
(installed height) Access Fittings.
2. Test the Access Fitting weld using the Hydrostatic Test Assembly #121328 supplied in the
Hot Tap Kit (See Chapter 2 and Figure 1).
3. The heat build-up from the welding process can (if proper weld procedure is not followed)
generate distortion and/or warpage of the Access Fitting body bore and internal threads. Also, the
full penetration weld root pass can leave a hard metal (weld) deposit on the inner periphery of
the base of the Access Fitting body. These conditions can create difficulties for later hot tapping,
probe insertion and coupon operations. In order to minimize such potential problems:
a. Visually inspect the internal and external access fitting body threads. The external
acme threads should be dressed with thread files if damage is apparent. Regardless of the
appearance of the internal threads, the Thread Chaser Assembly #125111 should be used
to clean up the threads and to correct possible warpage.
b. Pour approximately 1/2 ounce of cutting oil (if unavailable, motor oil can be used) into
the Access Fitting body. Use this procedure for all metals, except cast iron which should
be cut dry.
c. Attach the Square Nose End Mill #203530 to the Hot Tap Assembly. Thread the Hot
Tap hollow plug (1) into the Access Fitting body with the end mill on the fully retracted
position. Tighten the Hot Tap plug to a tight fit.
6 Chapter 3
d. Slowly advance the Hot Tap feed screw while rotating the drive shaft in a clockwise
direction using a suitable ratchet drive. The outer diameter of the end mill exactly fits an
Access Fitting body bore; thus, the initial cutting action serves to true-up the body bore if
distorted or warped. Subsequent cutting action, at the base of the body bore, will remove
the penetrated weld deposit.
NOTE: The depth or amount of cutting the end mill can perform is limited to less than
1/8” because of the increasing drag or friction caused by the non-cutting portions of the
end of the mill. Forcing this cutting action will only result in a broken Hot Tap drive
shaft. Also, because of the sharp curvature on small diameter pipes, it is virtually
impossible to remove all of the weld deposit; however, it will flatten the top or nearest
arc of the pipe giving the Hot Tap cutter an improved bite during the Hot Tap cut.
4. Remove the Hot Tap Assembly with Square Nose End Mill from the Access Fitting body. Use
the Chip Remover Assembly #123492 to clean the cuttings from the fitting and the Magnetic
Swab Assembly #121870 to clean the inner threads of the Access Fitting Body.
5. Again, as indicated in paragraph 3.b. pour 1/2 ounce of cutting oil into the Access Fitting
Body.
6. Select a cutter. Two different types of cutters are included in the Hot Tap Kit: a 6-tooth
(designed for small diameter or thin wall pipes – 1/4” or less) and a 4-tooth (designed for heavier
wall thicknesses).
7. Check the Hot Tap primary packing (3) and replace it if it is deformed or has particles
embedded into it. Inspect the Hot Tap for proper assembly, and the cutter teeth for good
condition.
8. Thread the Hot Tap hollow plug (1) into the Access Fitting. Be sure the cutter is fully retracted
and does not become jammed into the pipe. A good practice is to begin turning the drive shaft
nut (13). By hand, about 3 to 4 threads before the packing seats. This will help prevent the cutter
from hanging up (prior to the plug seating) on excessive internal weld bead, or the pipe if
insufficient weld gap was maintained.
9. If the cutter contacts an Access Fitting bore obstruction (for example, weld spatter) or the
pipe, cutter rotation must be started before fully tightening the Hot Tap plug. If not, fully tighten
the Hot Tap plug using a spanner wrench or a large adjustable wrench.
10. Cutting is normally done with a ratchet, by hand. A long ratchet (15”) is best. A 1” socket
will be needed to fit the drive nut. The best method is to have two people taking turns in cutting.
Cutting speeds will be approximately .006 to .025 inches per minute, (1/8 to 1/2 turns per minute
of feed screw and handle assembly travel). As the cutter cuts deeper, the chips produced will
slow the cutting speed. As a result, a certain amount of “recutting” will be done, causing a
variation in cutting speed.
Operating Instructions 7
Motorized power having suitable speed torque controls may also be used to drive the Hot Tap
cutter drive shaft. The rotating speed should be limited to less than 100 rpm and the required
torque is approximately 100 ft-lbs.
______________________________________________________________________________
For cutting by hand, see step a.
For motorized cutting, see step b.
______________________________________________________________________________
a. Turn the drive nut (13) clockwise until the cutter contacts the pipe and begins cutting.
Feed the cutter slowly at first by turning the feed screw and handle assembly (12)
clockwise. After cutting a short distance, back off the cutter and tighten the Hot Tap plug
(1) in the Access Fitting – continue cutting at a rate that produces smooth cutting.
b. Rotate the drive nut (13) with the motorized power, and slowly turn the feed screw and
handle assembly (12) until the pipe is contacted, and then faster until a smooth cutting
action occurs. The feed rate will vary depending upon motor rpm, power and type of
metal. Too slow a feed will cause excessive wear on the cutter and too fast can stall the
motor, pulling it out of the operators hands.
11. When cutting thick pipe walls (3/4” or more) the chips produced during cutting may prevent
the cutter from advancing. If so, for stroke lengths other than 14” Retrievers, the Chip Remover
Assembly #123492, should be used to clear away some of the chips. For the 14” stroke or shorter
Retriever only, the Chip Remover Assembly #127147 should be used. EITHER CHIP
REMOVER ASSEMBLY IS DESIGNED TO BE USED ONLY WITH THE RETRIEVER
AND SERVICE VALVE HOOK-UP.
12. After breaking through, continue feeding the cutter into the pipe another 1/4” or so, to clear
any burrs from the inside. The pressure can be felt due to the thrust load on the cutter and feed
screw and handle assembly.
13. Retract the cutter fully with the feed screw and handle assembly (12). It may be necessary to
turn the cutter slowly while doing this.
14. Loosen the two set screws (14) 3 to 4 turns.
15. Use an adjustable or open end wrench of 1-5/8” capacity to hold the Hot Tap plug (1), and
loosen the Hot Tap body (10) until the holes in the body line up with the spring pin (4).
16. Turn the drive shaft (13) and feed screw and handle assembly (12) until the spring pin (4) is
centered in the holes.
17. PARTIALLY DRIVE OUT the short spring pin (4) using the drift pin (15) and a brass
hammer. BE SURE TO ALLOW a portion of one end of the spring pin to rest on one side of the
8 Chapter 3
gland (7) wall and Hot Tap hollow plug (1) in order to release the drive shaft (9), yet preventing
the cutter from dropping into the pipe or vessel.
18. Unscrew the Hot Tap body (10) from the Hot Tap plug (1), removing the feed screw and
handle assembly (12), and drive shaft (9).
19. Drive in the long spring pin (16) (1-1/2” long) in the vacated hole opposite from the short
spring pin (4) until flush with the plug body (1). This will remove the remainder of the short
spring pin and retain the cutter during retrieval.
20. Install the service valve on the Access Fitting.
21. If a 14” stroke Retriever – RBS or RBSA – is to be used, the socket adapter must be
positioned in the first and third holes from the hex end. Longer stroke Retrievers will work with
the socket adapter in the standard position.
22. Retrieve the Hot Tap plug (1) as if it were a hollow plug assembly.
23. Remove the Hot Tap plug (1) from the Retriever. The cut slug or “core” should be retained
within the cutter and can be removed by prying out with a screw driver.
24. The Access Fitting thread should be cleaned of chips before attempting to install the solid or
hollow plug assembly. This can be done by using the Surge Tube Assembly #123672, the Thread
Brush Assembly #125116, or the Magnetic Swab Assembly #121870. Normally, the surge tube
works the easiest.
The Retriever should be flushed with solvent and lubricated, to remove any chips that may have
entered, before the plug is reinstalled.
25. Install the solid or hollow plug assembly to place the fitting in service.
26. Any chips that may have entered the service valve should be cleaned out before using the
valve again to prevent damage to the seats.
9
Chapter 4
Disassembly-Assembly (Hot Tap)
(Refer to Figure 2)
A. Disassembly:
1. Loosen the set screws (14) 3 to 4 turns in the Hot Tap body (10).
2. Align the holes in the Hot Tap plug (1) and body (10). Retract the cutter until the spring pin
(4) is centered in the holes.
3. Drive out the short spring pin (4) or the long spring pin (16) (whichever is in place) with the
drift pin (15).
4. Unscrew the Hot Tap plug (1) from the body (10).
5. Remove the cutter by pulling it out of the Hot Tap plug (1).
6. Remove the set screw (2), and turn the gland (7) clockwise to remove it.
7. The polypack (8) can be removed from the gland (7) with an o-ring pick.
8. Collapse the feed screw and handle assembly (12) until the hex of the drive shaft (9),
protrudes out past the end of the Hot Tap body (10).
9. Hold the hex and of the drive shaft (12) in a vise and turn the drive nut (13) counterclockwise.
10. Remove the drive nut (13), three springs (20), and the thrust washer (19).
11. Pull the drive shaft (9), spacer (17), and thrust bearing (11) from the body (10).
B. Assembly:
1. Install the snap ring (18) and spacer (17) on the drive shaft (9). Grease the thrust bearing (11)
and place it on the drive shaft (9).
2. Clean and grease the feed screw and handle assembly (12), thread and screw it about 1-1/2”
into the Hot Tap body (10).
10 Chapter 4
3. Push the drive shaft (9) up through the feed screw bearings (11). Install the washer (19), three
springs (20) and the drive nut (13). The drive nut need not be wrenched up as it will tighten
during use.
4. Thread the Hot Tap gland (7) into the Hot Tap plug (1) by turning it counter-clockwise.
5. Align the set screw hole and install the half-dog set screw (2)
6. Install the polypack (8) being careful not to nick the seal or dislodge the o-ring.
7. Extend the drive shaft (9) until the hex can be engaged in the Hot Tap cutter.
8. Align the holes and drive in the short spring pin (4). Be sure the pin is centered in the cutter
shank or else the will gouge the bronze gland (7) during use.
9. Thread the Hot Tap plug (1) into the body until it bottoms. Tighten the two set screws (14).
10. Turn the drive shaft (9) to be sure the cutter turns freely and advances properly.
Disassembly-Assembly (Hot Tap) 11
Figure 2
12 Chapter 4
PARTS LIST: 2” Hot Tap Assembly #126431 (See Fig. 2); component assembly of 2” Hot Tap Kit
#126248
Item
Quantity
Description
Part No.
1
1 each
2” Hot Tap Hollow Plug 4.87-GA
126435
2
1 each (3)
Set Screw, 10-32 x 3/16 half dog
129154
3
4 each (13)
2” Hot Tap Primary Packing, TFE
126445
4
2 each (31)
Spring Pin (23-S-187-0937)
126452
5
1 each (1)
2” Hot Tap Magnet
126434
6
1 each
2” Hot Tap Cutter, 4-tooth
203510
7
1 each (1)
2” Hot Tap Gland
126436
8
1 each (1)
2” Hot Tap Polypack
126437
9
1 each (1)
2” Hot Tap Drive Shaft
126438
10
1 each
2” Hot Tap Body
126439
11
1 each (1)
2” Hot Tap Bearing
123804
12
1 each
2” Hot Tap Handle & Feed Screw
126440
13
1 each (1)
2” Hot Tap Drive Nut
126442
14
2 each (2)
Set Screw, 1/4-20 x 5/8
129575
15
1 each
Drift Pin
123806
16
1 each (10)
Spring Pin (23-S-187-1500)
117941
17
1 each
2” Hot Tap Spacer
126450
18
1 each
Snap Ring (5100-59)
129028
19
1 each (1)
2” Hot Tap Thrust Washer
126444
20
3 each (3)
Belleville Spring (BS-39)
129023
21
1 each
Snap Ring Pliers
129127
13
Chapter 5
Care & Maintenance
The Cosasco 2” Hot Tap requires little care and maintenance except that which is required by
any precision tool.
The threaded areas should be inspected during assembly for nicks and kept lubricated. Minor
thread repair should be done with thread files. Emery paper can be used to smooth the tops of the
threads if they become sharp. The Hot Tap gland should be kept clean and lubricated. Dropping
or rough handling of the gland may cause it to become out of round. If so, placing the gland on
the cutter shank and tapping it with a brass hammer can often times bring it back into round.
If the gland requires replacement, it will be necessary to index and drill a hole for the set screw.
The gland should be installed in the plug, and the location marked. Remove the gland and drill a
hole through with a 9/64” drill bit, and then remove any burrs.
The Hot Tap cutters are precision ground milling tools made of high quality tool steel. They are
capable of providing a long life. Resharpening by hand is not recommended, as the cutting
geometry and symmetry are important. The cutters can be resharpened by returning them to
Cosasco for repair.