Three Types
Cone (TC), basket (TB) with a flat bottom, and plate (TP). Cones hold the most debris for their size; plates need the least room; baskets sit in between.
Commissioning strainers
Temporary Cone, Basket & Plate Strainers
A new pipeline carries weld slag, welding rods, scale, sand and tools left behind during construction, and the first flow sweeps them towards the pumps, compressors, meters and valves. A temporary strainer catches them: a perforated cone, basket or plate on a thin ring that fits between two existing flanges, with no change to the pipe. It stays in for commissioning and start-up and comes out when the line runs clean. Peltech makes temporary strainers to size in Malaysia, in stainless steel and other alloys, for every flange rating.
3/4 to 30 in24 in standard; larger on request
100 to 300 %open area; 150 % standard
150 to 2500 lba ring for every flange rating
SS304, SS316duplex, Monel, Hastelloy on request
Inside the line
What a Temporary Strainer Is Made Of
Loading the 3D model…
1
Flange Ring
A flat ring that sits between the two pipe flanges, inside the bolt circle, sized for the flange rating. Ring-joint rings for RTJ flanges.
2
Tab Handle
A tab, 1 inch wide and 3 inches long, that stays outside the flanges: it shows that a strainer is in the line and carries the size, the rating and the flow direction.
3
Perforated Screen
A cone, a basket with a flat bottom, or a flat plate, perforated with 1/8 inch (about 3 mm) holes on 3/16 inch (about 5 mm) centres as standard.
4
Mesh Lining
A woven mesh for a finer cut, always on the upstream side, so the flow presses it onto the perforated screen behind it.
5
Stiffening Band
A band or cross bracing on cone and basket types keeps the screen in shape against the pressure of the flow.
6
Gaskets
One gasket on each side of the ring, so the joint seals as it does without the strainer.
7
Pipe Flanges
The existing flanges of the line: the strainer fits between them without any change to the pipe.
8
Flange Bolts
The bolts pass outside the ring; the flanges are spread a little to put the strainer in and take it out.
How it works
Six Steps from First Flush to Clean Line
A temporary strainer works on the same principle as a basket strainer: the flow enters its open end and leaves through the perforated wall, from the inside out, so the debris stays inside. The cone shape keeps the caught debris at the tip, away from most of the open area, so the flow continues while the strainer fills. The diagram and the six steps below follow a new line from its first flush to clean running.
Step 1 of 6: Flushing StartsThe first flow through a new line sweeps along weld slag, rods, scale and dirt left from construction.
Flushing flow with debrisStrained flowDebris held in the strainer
1
Flushing Starts
The first flow through a new line sweeps along weld slag, rods, scale and dirt left from construction.
2
Through the Screen
The flow enters the open end of the strainer and leaves through its perforated wall, from the inside out.
3
Debris Caught
The debris stays inside and is carried to the tip of the cone, so the rest of the screen keeps working.
4
Watch the Pressure Difference
Gauges on each side show the pressure difference rising as the strainer fills; it must be cleaned before the difference gets high.
5
Pull and Clean
The line is stopped, the flanges are spread and the strainer is pulled out by its tab, emptied and put back.
6
Remove After Start-Up
When the line runs clean, the strainer is taken out for good and the flanges are closed with a new gasket.
Open area. The holes of the screen together are compared with the bore of the pipe: 150 % means one and a half times the pipe area. More open area means a lower pressure drop and more room for debris before the flow is restricted; we make 100 to 300 %.
Mesh on the upstream side. A mesh lining must face the flow, with the perforated screen behind it as its backing; the other way round, the flow would push it off. That is why the flow direction is marked on the tab.
Temporary means temporary. A temporary strainer is light and is not meant to stay in the line: watch the gauges during start-up, clean it as often as needed, and take it out when the line runs clean.
Design and construction
Made to Size in Malaysia for Every Flange Rating
Made to the Flange
The ring is cut to sit inside the bolt circle of the flange rating, ANSI 150 to 2500 lb, with ring-joint rings for RTJ flanges and rings for JIS or DIN flanges on request.
Open Area
100 to 300 % of the pipe bore, 150 % as standard. Cone and basket types can be made inverted, pointing upstream, which gives more open area for the same length.
Screens
1/8 inch holes on 3/16 inch centres as standard; other perforations, a single ply of heavy wire mesh, or a mesh lining for a finer cut.
Materials
SS304 and SS316 as standard; duplex and super duplex stainless steel, 904L, Monel, Hastelloy and other alloys on request, to match the pipe.
Stiffeners
Bands or cross bracing on cone and basket types for high flows and large sizes, so the screen does not collapse.
Tab Handle
A 1 x 3 inch tab on every strainer, marked with the size, the rating and the flow direction, and visible from outside the flanges.
Sizes
From 3/4 inch (20 mm) to 24 inches (600 mm) as standard, and up to 30 inches for large projects; larger on request.
Checks and Documents
Every strainer is checked against its drawing; EN 10204 3.1 material certificates, a certificate of conformance, positive material identification and pickling and passivation when the project asks for them.
Applications
Where Temporary Strainers Are Used
Temporary strainers protect a plant during its first weeks, and again after a shutdown, when the piping has been opened and closed. Contractors and plant owners fit them at every place where debris would do harm. These are the usual duties.
New Plants
Commissioning and start-up
In front of pumps, compressors, turbines, meters and control valves of a new plant, for the first flushing and the start-up.
Compressor and Pump Suction
Rotating equipment
On the suction side of compressors and pumps, where a single piece of weld slag can damage the machine.
Shutdowns and Turnarounds
After maintenance
After a shutdown, when lines have been cut, welded or opened, until the system runs clean again.
Oil and Gas, Refining, Petrochemical
Process and utility lines
Hydrocarbon, gas, steam and utility lines on refineries, LNG, petrochemical and chemical plants, at ratings up to 2500 lb.
Edible Oil and Process Plants
Refineries and factories
Oil, water and steam lines in edible oil refineries, oleochemical plants and food factories.
Steam, Water and Fire Water
Boiler and utility systems
Boiler feed, steam, cooling-water and fire-water lines during flushing and commissioning.
Where It Sits in a Line
New line
slag, rods and scale from construction
Flushing
the first flow sweeps them along
Temporary strainer
between two flanges
Pump or compressor
protected during start-up
Clean running
the strainer comes out
Permanent strainer
if the duty needs one
Place a pressure gauge on each side of the strainer, or a differential gauge, and check it often during flushing and start-up; where debris will keep arriving, a permanent basket strainer takes over.
When a Temporary Strainer Is the Right Choice
- Commissioning and start-up of new pipework, and the first runs after a shutdown.
- Protection of pumps, compressors, turbines and meters from construction debris.
- A line that has no permanent strainer, with a pair of flanges in front of the equipment.
- High flange ratings, ring-joint flanges and special alloys, made to the line.
When Another Strainer Is Better
- Debris that keeps coming in normal service: a permanent basket strainer.
- A line that must not stop for cleaning: a duplex basket strainer.
- Small lines, steam or gas in service: a Y-strainer.
For permanent protection see the LEAKPROOF simplex basket strainer, the LEAKPROOF duplex basket strainer or the LEAKPROOF Y-strainer.
We make every temporary strainer ourselves, in our works in Malaysia: cone, basket and plate types for new plants and shutdowns at refineries, LNG, petrochemical, chemical and power plants, edible oil refineries and water works, mostly for the contractors who build them, in Malaysia, Singapore and Indonesia, from small lines to large projects.
Types and dimensions
Cone, Basket and Plate Types
Each strainer is made for its line: the pipe size, the flange rating, the type, the open area, the perforation or mesh and the material. The tables give the ring and the lengths of our standard cone and basket types.
Cone Type, TC
Also called a witch hat strainer: the most open area and room for debris for its length.
Basket Type, TB
A tapered basket with a flat bottom, shorter than a cone of the same open area.
Plate Type, TP
A flat perforated plate on its ring: the least room in the pipe, for light debris.
Ring Dimensions
| Size (in) | Size (mm) | OD 150/300 lb | OD 600 lb | OD 900 lb | OD 1500 lb | ID | D |
|---|---|---|---|---|---|---|---|
| 3/4 | 20 | 54 | 64 | 67 | 67 | 16 | 8 |
| 1 | 25 | 64 | 70 | 76 | 76 | 19 | 10 |
| 1-1/2 | 40 | 83 | 92 | 95 | 95 | 32 | 16 |
| 2 | 50 | 102 | 108 | 140 | 140 | 44 | 22 |
| 2-1/2 | 65 | 121 | 127 | 162 | 162 | 57 | 29 |
| 3 | 80 | 133 | 146 | 165 | 171 | 70 | 35 |
| 4 | 100 | 171 | 191 | 203 | 206 | 95 | 48 |
| 5 | 125 | 194 | 238 | 244 | 251 | 117 | 59 |
| 6 | 150 | 219 | 263 | 286 | 279 | 137 | 68 |
| 8 | 200 | 276 | 318 | 356 | 349 | 187 | 94 |
| 10 | 250 | 337 | 397 | 432 | 432 | 238 | 119 |
| 12 | 300 | 406 | 454 | 495 | 517 | 279 | 140 |
| 14 | 350 | 441 | 483 | 517 | 575 | 311 | 156 |
| 16 | 400 | 511 | 555 | 572 | 638 | 356 | 178 |
| 18 | 450 | 540 | 603 | 635 | 702 | 400 | 200 |
| 20 | 500 | 597 | 676 | 695 | 753 | 445 | 222 |
| 24 | 600 | 708 | 784 | 835 | 899 | 540 | 270 |
OD: outside diameter of the ring for each flange rating. ID: inside diameter of the ring, all ratings. D: bottom of the basket type. All dimensions in mm. Rings for 2500 lb flanges and sizes above 24 inches are made to the line.
Lengths, 1/8 in Holes on 3/16 in Centres
| Size (in) | Size (mm) | Cone 100 % | Cone 150 % | Cone 200 % | Basket 100 % | Basket 150 % | Basket 200 % |
|---|---|---|---|---|---|---|---|
| 3/4 | 20 | 29 | 43 | 57 | 19 | 29 | 38 |
| 1 | 25 | 41 | 64 | 84 | 29 | 43 | 57 |
| 1-1/2 | 40 | 56 | 86 | 114 | 38 | 57 | 76 |
| 2 | 50 | 76 | 114 | 152 | 51 | 76 | 102 |
| 2-1/2 | 65 | 81 | 127 | 170 | 56 | 86 | 114 |
| 3 | 80 | 102 | 159 | 216 | 70 | 108 | 145 |
| 4 | 100 | 130 | 200 | 270 | 89 | 136 | 183 |
| 5 | 125 | 165 | 257 | 356 | 114 | 171 | 232 |
| 6 | 150 | 207 | 330 | 432 | 140 | 216 | 289 |
| 8 | 200 | 259 | 406 | 559 | 178 | 272 | 381 |
| 10 | 250 | 330 | 508 | 686 | 219 | 356 | 457 |
| 12 | 300 | 406 | 610 | 838 | 267 | 432 | 559 |
| 14 | 350 | 432 | 686 | 914 | 292 | 457 | 610 |
| 16 | 400 | 508 | 787 | 1041 | 356 | 533 | 711 |
| 18 | 450 | 584 | 889 | 1194 | 406 | 610 | 813 |
| 20 | 500 | 635 | 991 | 1346 | 432 | 686 | 889 |
| 24 | 600 | 762 | 1194 | 1600 | 533 | 813 | 1067 |
Length L in mm from the ring to the tip of the cone or the bottom of the basket, for the open area shown (compared with the bore of Schedule 40 pipe; 150 % standard). Other perforations or a mesh lining change the open area.
When Ordering, Tell Us
| Pipe size | Nominal size, and the pipe schedule if it is not 40 |
| Type | Cone, basket or plate; normal or inverted |
| Flange rating | ANSI 150 to 2500 lb, raised face or ring joint; JIS or DIN on request |
| Open area | 100, 150, 200 or 300 % |
| Screen | Perforation, or perforation with a mesh lining, and the mesh size |
| Flow direction | Always, when the screen is mesh-lined |
| Material | SS304, SS316, duplex, Monel, Hastelloy or other |
| Documents | EN 10204 3.1 material certificates, certificate of conformance, PMI or other checks |
Dimensions are for our standard strainers and may change; the drawing sent with each quotation gives the dimensions of the strainers we make for you.
Spares and re-meshing
Spare Strainers and Re-meshing
A temporary strainer is often used again: at the next shutdown, in another line, or after its mesh has been renewed. We make spare strainers to the same drawing and re-mesh used ones in our own works.
Spare Strainers
A second strainer on site means the line is back in service as soon as the flanges are closed.
Re-meshing
Torn or blocked mesh linings renewed on the old screen and ring.
Long Baskets
Tall perforated baskets on a ring for lines with more room or more debris.
Special Elements
Wedge-wire, mesh and stiffened cones made to a drawing for special duties.
FAQ
Frequently Asked Questions
What is a temporary strainer?
A perforated cone, basket or plate on a thin ring that fits between two pipe flanges. It catches the debris left in a new or repaired line during flushing and start-up, and is taken out when the line runs clean. The cone type is also called a witch hat or conical strainer.
Cone, basket or plate: which do I need?
A cone holds the most debris and keeps the flow going longest, so it is the usual choice. A basket is shorter for the same open area. A plate needs almost no room in the pipe, for light debris or tight spaces.
What does 150 % open area mean?
The holes of the screen add up to one and a half times the area of the pipe bore. More open area means a lower pressure drop and more room for debris; we make 100 to 300 %, with 150 % as standard.
Which way round is it fitted?
Normally with the open end facing the flow and the tip pointing downstream, so the flow passes from the inside out. The flow direction is marked on the tab; a mesh-lined strainer must always be fitted that way round.
How long does a temporary strainer stay in the line?
Through flushing, commissioning and the first runs, while the gauges show debris arriving. Clean it whenever the pressure difference rises, and take it out once the line runs clean.
What do you need to quote?
The pipe size and schedule, the flange rating and facing, the type, the open area, the perforation or mesh and its flow direction, and the material. A line list with these columns is the easiest way to send many strainers.
Can you make strainers for high ratings and special alloys?
Yes. We make rings for ANSI 150 to 2500 lb flanges, ring-joint rings for RTJ flanges, sizes up to 30 inches, and strainers in duplex and super duplex stainless steel, 904L, Monel, Hastelloy and other alloys.
Can a used temporary strainer be re-meshed?
Yes. Send it back and we will renew the mesh lining on the old screen and ring, or make a spare to the same drawing.
Need a Quote or a Sizing Check?
Send us your duty, a drawing or a photo of your existing unit. A Peltech engineer will reply with options and a quotation.