Flushing Ring Product Overview

The SIYelectric Flushing Ring is a process connection accessory used together with flanged pressure transmitters, diaphragm seal pressure transmitters, single flange level transmitters, and dual flange differential pressure level transmitters.

It is normally installed between the process flange and the diaphragm seal flange. The flushing ring provides one or two side ports, which can be used for flushing, draining, venting, pressure release, or calibration connection.

In actual industrial applications, diaphragm seal transmitters are often selected for difficult media such as viscous liquids, slurry, crystallizing fluids, corrosive chemicals, polymerizing media, or fluids containing solids. These media may accumulate near the diaphragm surface and affect measurement accuracy. A flushing ring gives operators a practical way to clean or drain the measuring area without frequently removing the transmitter from the process connection.

Product Description

A flushing ring is not a measuring instrument itself. It is an auxiliary part used to improve the maintenance convenience and measurement reliability of diaphragm seal systems.

When a flange-mounted transmitter is installed directly on a tank, vessel, pipe, or reactor, the diaphragm seal is exposed to the process medium. If the medium is clean and non-sticky, normal installation may be enough. But for dirty, viscous, crystallizing, or corrosive media, deposits may build up around the diaphragm seal over time.

Without a flushing ring, cleaning the diaphragm seal area usually requires removing the transmitter or opening the process flange. This can increase maintenance time, leakage risk, and shutdown cost.

By adding a flushing ring, operators can connect flushing liquid, purge gas, drain valves, vent valves, or calibration equipment through the side ports. This allows easier cleaning, pressure release, and inspection of the measuring point.

How a Flushing Ring Works

The flushing ring is mounted as a spacer between two flanges:

Process Flange → Flushing Ring → Diaphragm Seal Flange → Transmitter

The side port on the flushing ring provides an additional access point to the space near the diaphragm seal. Depending on the site requirement, this port can be connected to:

• a flushing water line
• a solvent cleaning line
• a purge gas line
• a drain valve
• a vent valve
• a calibration or test connection
• a pressure release connection

For dual flange differential pressure level transmitters, flushing rings can be installed on one side or both sides, depending on the vessel structure, medium condition, and maintenance requirement.

Key Features

Flushing Access for Diaphragm Seal Systems

The flushing ring provides a convenient access point for cleaning the diaphragm seal area. This is especially useful when the process medium may leave residue, crystallize, or block the measurement connection.

Draining and Venting Function

The side port can be used to drain residual liquid or vent trapped gas before inspection, calibration, or transmitter removal. This improves maintenance safety and reduces the risk of uncontrolled pressure release.

Calibration and Test Connection

The flushing ring can also provide a connection point for calibration tools, test gauges, pressure sources, or other maintenance devices.

Helps Reduce Measurement Problems

By allowing cleaning and flushing near the diaphragm, the flushing ring helps reduce problems caused by buildup, sediment, crystallization, or blockage.

Suitable for Flanged Pressure and Level Instruments

It can be used with flanged pressure transmitters, diaphragm seal pressure transmitters, single flange level transmitters, and dual flange differential pressure level transmitters.

Multiple Material Options

The flushing ring can be supplied in different materials according to the process medium, such as SS304, SS316, SS316L, Hastelloy, Monel, PTFE-lined options, or other corrosion-resistant materials.

Custom Side Port Options

Common side port options include 1/4″ NPT, 1/2″ NPT, G thread, or customized thread connections according to the project requirement.

Technical Specifications

Applications

Flanged Pressure Transmitters

Used with flanged pressure transmitters to provide flushing, venting, and draining access at the process connection.

Diaphragm Seal Pressure Transmitters

Suitable for diaphragm seal pressure transmitters used in tanks, pipelines, vessels, reactors, and chemical process equipment.

Single Flange Level Transmitters

Used in liquid level measurement applications where the diaphragm seal is mounted directly on a tank or vessel flange.

Dual Flange Differential Pressure Level Transmitters

Suitable for closed tanks, pressurized vessels, and differential pressure level measurement systems. The flushing ring can be installed on the high-pressure side, low-pressure side, or both sides.

Chemical and Petrochemical Processes

Used for corrosive, viscous, crystallizing, polymerizing, or dirty process media where diaphragm cleaning and maintenance access are important.

Wastewater and Slurry Applications

Suitable for applications where suspended solids, sludge, sediment, or sticky media may accumulate around the diaphragm seal.

Food, Beverage, and Pharmaceutical Auxiliary Systems

Can be used in compatible process or utility systems where cleaning and flushing access is required. For direct sanitary service, surface finish, dead-leg design, gasket material, and sanitary connection requirements should be confirmed separately.

Advantages

• Provides flushing, draining, venting, and calibration access for diaphragm seal transmitters.
• Helps clean the diaphragm seal area without frequently removing the transmitter.
• Reduces blockage risk in viscous, crystallizing, dirty, or slurry media.
• Improves maintenance convenience for flange-mounted pressure and level instruments.
• Supports safer pressure release before transmitter inspection or removal.
• Suitable for pressure transmitters and differential pressure level transmitters.
• Side ports can be connected to drain valves, vent valves, flushing lines, or test devices.
• Material and flange standards can be customized according to site requirements.
• Useful for chemical, petrochemical, wastewater, slurry, and difficult media applications.

Selection Notes

When selecting a flushing ring, the following details should be confirmed:

1. Instrument type
   Confirm whether it is used with a flanged pressure transmitter, single flange transmitter, or dual flange differential pressure level transmitter.
2. Flange size and standard
   Confirm the flange size, pressure rating, sealing face, and standard, such as ASME, EN, DIN, JIS, or GB.
3. Side port requirement
   Confirm whether one side port or two side ports are required. Also confirm the thread size, such as 1/4″ NPT or 1/2″ NPT.
4. Material compatibility
   Select SS316L, Hastelloy, Monel, PTFE lining, or other materials according to medium corrosion and temperature.
5. Medium characteristics
   Confirm whether the medium is viscous, crystallizing, corrosive, dirty, high-temperature, toxic, or easy to block.
6. Installation thickness
   The thickness of the flushing ring affects bolt length and installation space. Bolt and gasket compatibility should be checked before installation.
7. Flushing method
   Confirm whether the site will use water, solvent, steam, gas, or another cleaning medium for flushing.