The Watts 77SI 1/2 is a 1/2" wye-pattern strainer with NPT connections that removes pipeline debris and particulates to protect downstream equipment. It ships with a 20 mesh 304 stainless steel screen. It features a cast iron body and a ptfe seat. Rated to 400 psi.
This cast iron wye pattern strainer, 1/2 inch Watts Model 77SI, is designed to protect system components from dirt, rust, and other damaging debris in the piping system. It is used in steam and liquid applications and it is furnished with a machined seat that allows the screen to be self-aligning to assure a perfect fit.
Features
- Wye pattern
- Cast iron body
- Threaded connections
- Tapped retainer cap
- Includes: Strainer
Common Questions
- What mesh or screen size does it come with?
- 77SI 1/2 ships with a 20 mesh 304 Stainless Steel screen (20 openings per linear inch). That is the standard screen Watts supplies for this body at this pipe size -- the screen size is not called out in the model number, so it varies by size across the series.
- Can I get a finer or coarser screen?
- Yes. Watts builds this body with a range of screens and encodes the choice in the model number, so a finer or coarser screen is a different part number rather than an accessory. This one is 20 mesh. Finer screens catch smaller particles but clog faster and cost more pressure drop, so size the screen to the debris you actually have.
- Can I use this on steam?
- Yes. 77SI 1/2 is rated 250 psi WSP on steam, which is a separate and much lower limit than its 400 psi WOG (cold water, oil, gas) rating. Do not size steam service off the WOG number.
- Does it have a blowoff / blowdown port?
- Yes. The retainer cap/cover is tapped for a blowoff connection, so you can flush accumulated debris by pulling the plug or piping a blowdown valve to it -- no need to break the strainer apart. The closure plug is included.
- What is the "seat material" on a strainer?
- A strainer has no seat -- nothing closes against anything. The PTFE called out here is the retainer-cap seal (the gasket between the cap and the body), which is what limits the temperature and chemical compatibility of the closure.
Specifications
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Type: Strainer
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Size: 1/2"
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Connection: NPT
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Body Material: Cast Iron
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Cap Seal / Gasket Material: PTFE
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Max Pressure (WOG, psi): 400
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Application: Steam
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Pack Quantity: 10
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Country of Origin: Taiwan
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Warranty: 1 Year Limited
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MPN: 77SI 1/2
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Lead-Free: No
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Strainer Pattern: Wye
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Screen Type: Mesh
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Screen Mesh: 20
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Screen Material: 304 Stainless Steel
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Blowoff / Drain Tapping: Yes
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Blowoff Plug Included: Yes
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Max Steam Pressure (WSP, psi): 250
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Body Coating: None
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Alternate Screens Available: Yes
