TYPES OF STRAINER

Straight and angle type strainer

Straight and angle strainer have the same function as that of y-type and have a similar function. These are used in where y type strainer does not suit the pipework.

Straight angle type strainer

Basket or T-type strainer

This type of strainer has a vertical chamber, which is comparatively larger than Y-type. The basket strainer features top removal of the screen. The screen is in the form of a basket, with a lifting handle so that the particulate captured by the screen can be easily removed. It has a greater straining area and is hence used for liquid applications.

T –type strainer can only be fitted on horizontal pipelines. The arrangement of this type is done in duplex type. Two strainers are arranged in a parallel position. One strainer is called primary and the other is a secondary strainer. During maintenance or while cleaning the system is operating as the flow is diverted from either of the two strainers.

T-type of Basket Strainer

 

Magnetic Strainers:

Magnetic inserts are placed in the strainer. These inserts attract only ferromagnetic particles. The magnetic materials are enclosed in an inert material so that they are free from corrosion. The fluid is passed over the insert at slow velocity and it captures the metal particles.

Self-Cleaning Strainers:

The debris on the screen can be cleaned without interrupting the process. Cleaning can be done manually or automatically. Self-cleaning strainers remove the debris without disturbing the process.

Mechanical Type self-cleaning:

Cleaning the screen in this type is employed by using a brush or scraper. The debris falls down in collection are at the bottom of the strainer.

 

Temporary Strainer:

These are used for the protection from debris during the starting load. This is fitted in between two flanges. These are used temporarily when the plant has been newly installed.

Quick opening covers and cover removal aids:

The quick opening covers and cover removal aids available on fabricated strainers are distinguished by their compact size and functional design. Materials of construction are in accordance with ASME specifications and manufacturing complies with the applicable rules of the ASME code for pressure piping and with the ASME Boiler and Pressure Vessel Code.

1. Cover Type BD-Davit Assembly

The Davit assembly is used to enable the user to swing the cover away from the strainer in order to facilitate basket or screen removal for cleaning. Its primary use is for larger sized strainers where

cover removal is difficult. The Davit assembly is an inexpensive alternative to quick release covers, especially when operating conditions require a bolted cover to be utilized.

BD-Davit Assembly

 

2. Cover type H-T-Bolt Hinged Cover

The T-bolt hinged cover is used for nominal pressure applications while being the most inexpensive closure available on fabricated strainers. The T- bolt hinged cover is opened quickly and easily using an O-ring as a seal. The operator merely loosens the T-bolts until they clear the holding lugs and allow the head to be swung open on its hinge. Camlock and break-over wrench assemblies are also available which eliminates the need for a wrench.

Cover Type H-T bolt hinged cover

 

3. Cover Type Y-yoke hinged cover

The yoke-hinged closure is a true ANSI-rated closure. Used primarily on high-pressure applications, yoke-hinged covers are available with 150%, 300%, 600%, 900%, and 1500% ANSI ratings. Yoke-hinged covers available on fabricated strainers are available with a wide range of operating aids ranging from the single-lever chain and sprocket drives to completely automated types. O-rings are utilized as the sealing member.

 

Cover Type Y-yoke hinged cover

4. Cover Type T-quick opening threaded cover

The threaded cover closure consists of a cap that fastens to a hub that has been welded to the strainer body. The female cap is threaded onto the male hub and an O-ring is utilized to make the seal. The placement of this O-ring prevents corrosion of the closure threads allowing for long, trouble-free service. The threaded closure can be utilized on both nominal and high-pressure applications.