Studded Tubes Studded Coils: An electric current is applied by contacts on the stud and tube and the resistance in this circuit produces the heat necessary for welding. Maximum resistance and therefore maximum heating occurs at the interface between the Stud and the tube. Pressure to forge the Stud and the tube together at the point of maximum heating is applied by various forms of tooling. These resistance welding processes produce a strong metallurgical bond between the stud and the tube while minimizing the heat affected zone (HAZ) in the tube. The use of pressure to forge the fin and the tube together helps to minimize the heat input necessary to make the weld. This Product is used in Fired Heaters under Very High Pressure & Temperature mainly in Petroleum refineries.

While it is not necessary to tell engineers what finned tubes are, or that their use is mandatory in cases of gas-liquid heat exchange where the film coefficient ratio is above 2, it is essential to tell the engineers that M.J.Patel's FINNED TUBES are backed by not only engineering excellence of manufacture, but also by our zealously guarded reputation for the finest quality of all our products.

T-FINS
Helical Straight strip wound on the tube are mechanically secured. The tubes are required grade of steel, the fins are aluminium for maximum tube-wall temperature of 121 deg C (250 deg F) and mild service conditions.

L-FINS
Helical strip bent to L-shape are mechanically secured to the tube with the outer surface of the tube totally enclosed with fins, for full fin contact and protection of tube from chemical action of the gas for maximum tube-wall temperature of 177 deg C (350 deg F) and moderate service conditions.

G-FINS
Helical straight strip wound into pre-cut grooves on the outer wall of the tube, fin and groove lips mechanically closed for maximum tube-wall temperature of 371 deg C (700 deg F) and extreme working conditions.

STUDDED TUBES
We have developed state of the art Technology for studded Pipes and Tubes of Carbon, Alloy and Stainless Steel Material having extremely low clear gaps between studs. These are used in Refinery Services and Fluidized Beds Boiler Coils.

LONGTITUDINALLY FINNED TUBES
We have indigenous developed automatic welding machines for giving low distortion Longitudinally welded Finned Tubes used in low capacity Boilers.

MAJOR APPLICATIONS
Process liquid cooling, Water cooling in chemical, petroleum, petrochemical and similar uses, Condensing, etc. Heating of air by steam in tubes. Air-conditioning and refrigeration industries, Metallurgical industries for cooling of quenching oil.

Water Wall Tubes: These are tubes in the Boiler where water is evaporated to steam and are also called Steam Generating Tubes. These Tubes also form the Walls of the Boiler and are hence called Water Walls or Water Wall Panels. These Tubes have very complicated shapes to allow Inspection openings and burner throats and fabrication require intricate binding on CNC programable bending Machines and checking on 3D layouts.

For pipes or tubes size 4 inch (10.2mm) OD and below, strip is fed into a set of forming rolls which consists of horizontal and vertical rollers so placed as to gradually from the flat strip in to a tube which is then allowed to pass the welding electrodes. The electrodes are copper disks connected to the secondary of a revolving transformer assembly.

The copper disk electrodes make contact on each side of the seam and temperature is raised to the welding point. Outside flash is removed by a cutting tool as the tube leaves the electrodes, inside flash is removed either by an air hammer or by passing a mandnel through the welded tube after the tube has been cooled. This is termed as Electric Resistance welded or ERW tube/pipe. If this ERW is being drawn further to get desired size of tubes or pipes, in cold condition is called as Cold Drawn welded or CDW.

For pressure vessels and reaction vessels in M.S., Al, Monel, Inconel, Cupronickel, etc., M.J. Patel employs the latest techniques for expanding tube ends into tube sheets. High pressure tests are always carried out on these heat exchangers before they leave the factory. Brass, copper, M.S. and S.S. tube sheets are used. Tube sheets are also made out of mild steel, alloy steel or stainless steel and baffle plates are made out of mild steel or stainless steel. M.J. Patel fabricates 'U' Tube heat exchangers which are used in fertilizer plants, petrochemical and power project complexes.

Fabrication of U-Tubes for Heat-Exchangers Spans at extremely Short Delivery time, even Extra long (23 mts.) is M.J. Patel's specialty. Tube Bending as per TEMA. Tubes to any specification and any length can be supplied in extremely short time due to our wide Mother Tube Stocks.

It is available in a variety of compositions, most popular of which are ASTM-A-213, Grade TD-321. (16% Cr, 8%N stabilized with titanium) and ASTM-A-213 Grade TD-347 (18% Cr, 8% Ni) stabilized with columbium. Either of these two may be used upto to 649oC. Care must be given to choice of welding rod to avoid brittleness in the welds.

In Boiler tubes, when water is evaporated to steam are called Steam Generating Tubes. These Tubes also form the Walls of the Boiler and are hence called Water Walls or Water Wall Panels. These Tubes have very complicated shapes to allow Inspection openings and burner throats and fabrication require intricate binding on CNC programmable bending Machines and checking on 3D layouts.

M.J.Patel can supply these tubes with ends swaged/reduced to smaller diameters or expanded to higher diameters. Ends can be supplied fully ground and annealed to facilitate Expansion or bevelled to weld to Header Stubs. The Water Wall Panels are High frequency tube to tube welded and then bent on Panel Bending Machines or the Gas tight panel can be made by welding Fins to tubes using Low Temperature Automatic Welding Machines using CO₂and Filler wires.

Studded Tubes Studded Coils: An electric current is applied by contacts on the stud and tube and the resistance in this circuit produces the heat necessary for welding. Maximum resistance and therefore maximum heating occurs at the interface between the Stud and the tube. Pressure to forge the Stud and the tube together at the point of maximum heating is applied by various forms of tooling. These resistance welding processes produce a strong metallurgical bond between the stud and the tube while minimizing the heat affected zone (HAZ) in the tube. The use of pressure to forge the fin and the tube together helps to minimize the heat input necessary to make the weld. This Product is used in Fired Heaters under Very High Pressure & Temperature mainly in Petroleum refineries.

While it is not necessary to tell engineers what finned tubes are, or that their use is mandatory in cases of gas-liquid heat exchange where the film coefficient ratio is above 2, it is essential to tell the engineers that M.J.Patel's FINNED TUBES are backed by not only engineering excellence of manufacture, but also by our zealously guarded reputation for the finest quality of all our products.

T-FINS
Helical Straight strip wound on the tube are mechanically secured. The tubes are required grade of steel, the fins are aluminium for maximum tube-wall temperature of 121 deg C (250 deg F) and mild service conditions.

L-FINS
Helical strip bent to L-shape are mechanically secured to the tube with the outer surface of the tube totally enclosed with fins, for full fin contact and protection of tube from chemical action of the gas for maximum tube-wall temperature of 177 deg C (350 deg F) and moderate service conditions.

G-FINS
Helical straight strip wound into pre-cut grooves on the outer wall of the tube, fin and groove lips mechanically closed for maximum tube-wall temperature of 371 deg C (700 deg F) and extreme working conditions.

STUDDED TUBES
We have developed state of the art Technology for studded Pipes and Tubes of Carbon, Alloy and Stainless Steel Material having extremely low clear gaps between studs. These are used in Refinery Services and Fluidized Beds Boiler Coils.

LONGTITUDINALLY FINNED TUBES
We have indigenous developed automatic welding machines for giving low distortion Longitudinally welded Finned Tubes used in low capacity Boilers.

MAJOR APPLICATIONS
Process liquid cooling, Water cooling in chemical, petroleum, petrochemical and similar uses, Condensing, etc. Heating of air by steam in tubes. Air-conditioning and refrigeration industries, Metallurgical industries for cooling of quenching oil.

Water Wall Tubes: These are tubes in the Boiler where water is evaporated to steam and are also called Steam Generating Tubes. These Tubes also form the Walls of the Boiler and are hence called Water Walls or Water Wall Panels. These Tubes have very complicated shapes to allow Inspection openings and burner throats and fabrication require intricate binding on CNC programable bending Machines and checking on 3D layouts.

For pipes or tubes size 4 inch (10.2mm) OD and below, strip is fed into a set of forming rolls which consists of horizontal and vertical rollers so placed as to gradually from the flat strip in to a tube which is then allowed to pass the welding electrodes. The electrodes are copper disks connected to the secondary of a revolving transformer assembly.

The copper disk electrodes make contact on each side of the seam and temperature is raised to the welding point. Outside flash is removed by a cutting tool as the tube leaves the electrodes, inside flash is removed either by an air hammer or by passing a mandnel through the welded tube after the tube has been cooled. This is termed as Electric Resistance welded or ERW tube/pipe. If this ERW is being drawn further to get desired size of tubes or pipes, in cold condition is called as Cold Drawn welded or CDW.

For pressure vessels and reaction vessels in M.S., Al, Monel, Inconel, Cupronickel, etc., M.J. Patel employs the latest techniques for expanding tube ends into tube sheets. High pressure tests are always carried out on these heat exchangers before they leave the factory. Brass, copper, M.S. and S.S. tube sheets are used. Tube sheets are also made out of mild steel, alloy steel or stainless steel and baffle plates are made out of mild steel or stainless steel. M.J. Patel fabricates 'U' Tube heat exchangers which are used in fertilizer plants, petrochemical and power project complexes.

Fabrication of U-Tubes for Heat-Exchangers Spans at extremely Short Delivery time, even Extra long (23 mts.) is M.J. Patel's specialty. Tube Bending as per TEMA. Tubes to any specification and any length can be supplied in extremely short time due to our wide Mother Tube Stocks.

It is available in a variety of compositions, most popular of which are ASTM-A-213, Grade TD-321. (16% Cr, 8%N stabilized with titanium) and ASTM-A-213 Grade TD-347 (18% Cr, 8% Ni) stabilized with columbium. Either of these two may be used upto to 649oC. Care must be given to choice of welding rod to avoid brittleness in the welds.

In Boiler tubes, when water is evaporated to steam are called Steam Generating Tubes. These Tubes also form the Walls of the Boiler and are hence called Water Walls or Water Wall Panels. These Tubes have very complicated shapes to allow Inspection openings and burner throats and fabrication require intricate binding on CNC programmable bending Machines and checking on 3D layouts.

M.J.Patel can supply these tubes with ends swaged/reduced to smaller diameters or expanded to higher diameters. Ends can be supplied fully ground and annealed to facilitate Expansion or bevelled to weld to Header Stubs. The Water Wall Panels are High frequency tube to tube welded and then bent on Panel Bending Machines or the Gas tight panel can be made by welding Fins to tubes using Low Temperature Automatic Welding Machines using CO₂and Filler wires.