Weflo Fig. 7101 / 7102 Ductile Iron Y-Strainer

Overview

The Weflo Fig. 7101 is a flanged ductile iron Y-strainer that removes scale, weld slag, sand and other debris from liquid pipelines before they reach pumps, control valves, heat exchangers and meters. Weflo offers it in sizes DN50 to DN600 with a rated working pressure of 16 bar (200 psi), while the companion Fig. 7102 covers the same size range at 25 bar (300 psi). According to the Weflo datasheet, both figures are WRAS Approved from DN50 to DN600 in ductile iron with an EPDM gasket for potable water, and the Fig. 7101 is certificated to ANSI/NSF 61 and 372 from DN50 to DN2000.

Seven Star LLC supplies the Weflo Fig. 7101 and Fig. 7102 to HVAC contractors, water utilities and industrial plants in Oman and the GCC, with engineering support in Muscat. Buyers looking for a chilled water strainer or a WRAS approved Y-strainer for a drinking-water main can rely on the published Weflo Fig. 7101 data for specification and approval submittals.

Operating Principle

A Y-strainer works by forcing all of the flow through a cylindrical perforated screen held in an angled leg of the body. Solids larger than the screen holes are retained on the inside of the screen and collect at the bottom of the leg, while clean liquid passes through the screen wall and continues downstream. The angled, Y-shaped geometry keeps the screen out of the main flow path, so the strainer can hold a reasonable volume of debris before the pressure drop rises significantly.

The Weflo Fig. 7101 screen is perforated 304 stainless steel with a spot-welded seam, located in a recessed seat in the body that keeps it accurately aligned. As general engineering guidance, the pressure difference across a strainer is the best indication of when the screen needs cleaning; many HVAC designers fit pressure gauges or test points on both sides so maintenance staff can monitor screen loading. The blow-off outlet on the cover allows accumulated debris to be flushed without fully dismantling the strainer.

Engineering Design of the Weflo Fig. 7101

Body and cover of the Weflo Fig. 7101 are ductile iron to EN 1563 EN-GJS-450-10 (ASTM A536 Grade 65-45-12). The screen is stainless steel to EN 10088 X5CrNi18-10 (ASTM A276 Type 304), and the cover gasket is graphite or EPDM. The blow-off plug is carbon steel C45 for the 1/2 inch size and grey cast iron EN-GJL-250 for plugs from 1 inch to 2 inch, and the cover carries an NPT or BSPT blow-off outlet finished with a plug. Fusion bonded coating or liquid epoxy painting protects the interior and exterior.

Flanges and drilling comply with EN 1092-2 PN16/25 and ANSI B16.1 Class 125. Standard screens have 1.5 mm holes with a 26 percent opening ratio for DN50 to DN80, and 3.0 mm holes with a 40 percent opening ratio for DN100 to DN600. Face-to-face lengths published by Weflo run from 230 mm at DN50 to 1450 mm at DN600, so the Weflo Fig. 7101 should be included in plant room layouts early, together with the clearance needed to withdraw the screen.

Key Features

Features of the Weflo Fig. 7101 and Fig. 7102 stated in the Weflo datasheet include the following.

• The Weflo Fig. 7101 is rated at 16 bar / 200 psi and the Fig. 7102 at 25 bar / 300 psi, both from DN50 to DN600.
• WRAS Approved for DN50 to DN600 in ductile iron body construction with an EPDM gasket for potable water.
• ANSI/NSF 61 and 372 certification for the Fig. 7101 from DN50 to DN2000.
• Screens are perforated 304 stainless steel with a spot-welded seam.
• A recessed seat in the body keeps the screen accurately aligned after cleaning.
• The cover has an NPT or BSPT blow-off outlet finished with a plug for flushing debris.
• Flanges and drilling comply with EN 1092-2 PN16/25 and ANSI B16.1 Class 125.
• Fusion bonded coating or liquid epoxy painting is applied to interior and exterior surfaces.

Industrial Applications

In HVAC plant the Weflo Fig. 7101 is most often installed on the suction side of chilled water, condenser water and hot water pumps, and upstream of chillers, plate heat exchangers, coils and pressure independent control valves whose small internal passages are vulnerable to debris. District cooling networks, hospitals, universities and commercial towers in Muscat and other GCC cities fit Y-strainers at these points to protect equipment during commissioning, when construction debris is at its worst, and through the life of the system.

Seven Star LLC supplies the Weflo Fig. 7101 and Fig. 7102 for HVAC, potable water, irrigation and industrial cooling services in Oman, including projects in Sohar and Salalah. Typical companions are pump sets such as the Grundfos Hydro MPC booster set, terminal control valves such as the Danfoss AB-QM PICV, and grooved pipework joined with the Victaulic Style 107N QuickVic coupling.

Technical Specifications

Weflo Fig. 7101 values in this table are taken from the Weflo datasheet for Fig. 7101 and Fig. 7102.

Selection and Installation Notes

The guidance in this section is general engineering practice rather than a Weflo instruction. Install the strainer with the flow arrow in the correct direction and with the screen leg pointing downwards in horizontal pipework, so debris collects away from the flow and can be flushed through the blow-off connection. Leave enough free space below or beside the cover to withdraw the screen; on large sizes this clearance is substantial and is easy to overlook on congested plant room drawings.

During flushing and commissioning of a new chilled water system, screens load quickly, so it is good practice to inspect them frequently in the first weeks of operation. Where finer filtration is required for sensitive equipment, Weflo notes that other material types are available on request, and Seven Star LLC can discuss alternative screen options with the factory before order.

How to Order

To obtain a quotation for the Weflo Fig. 7101 or Fig. 7102, send Seven Star LLC an RFQ with sizes, pressure rating, flange standard and the service fluid. Our Muscat engineers can confirm availability and lead time, share the Weflo technical datasheet available for download on this page, and support HVAC and water projects throughout Oman and the GCC.