Fixed Flow Rate Orifices

Various fixed flow rate orifices

Fixed Flow Rate Orifices:
Constant Flow Assured

In applications where a constant flow of water is needed despite pressure differential changes, the  Fixed Flow Rate Orifice (FFRO) from O’Keefe Controls Co. provides an excellent solution. The innovative design of the unit compensates for pressure differential increase by reducing the area of the orifice, resulting in constant flow over a differential pressure range of 15 to 150 psig. With an operating temperature range of 32ºF to 160ºF, they are suitable for a number of applications across many industries. 

A Cost-Effective, Tamperproof Solution

When unwanted adjustments to a set water flow rate for a process could disrupt flow control or cause increased water costs, the “no adjustment” feature of O’Keefe Controls Co. Fixed Flow Rate Orifices makes them particularly attractive as a solution.

The durable construction features a deformable opening which decreases in size as the pressure differential increases. Put simply, this innovative design allows the device to respond to increased pressure differential by reducing the area of the orifice, resulting in constant flow despite changes in differential pressure within its range.

If managing maintenance costs is a concern, Fixed Flow Rate Orifices from O’Keefe Controls Co. are an optimum choice for water flow rate control. Installed in a system, these devices provide extremely reliable service over a very long, trouble-free operating life.

Fixed Flow Rate Orifices

Various fixed flow rate orifices shown

CLICK HERE to view our catalog of Fixed Flow Rate Orifice offerings


• Flow rate: 0.2 – 10 gal per minute

• Pressure range: 15 to 150psi

• Temperature range: 32ºF to 160ºF

• Available in 1/4″, 3/8″, 1/2″, 3/4″ NPT

• Brass body; Buna-N diaphragm

• Tamperproof construction

Typical Applications:

• Water Flow Rate Control

• Heating and Cooling Systems

• Water Spray

• Film Process and Rinse

• Water Conservation

• Flow Rate Limitation


Give us a call to speak to a technical Customer Service Representative. 


Applications for Fixed Flow Rate Orifices

CNC laser cutting procees

FFROs can be incorporated into the heat transfer control processes in such applications as laser cutting and marking.

Heat Transfer Process Control

Industrial processes such as CNC milling, machining and laser cutting and marking require varying types of cooling mechanisms to dissipate the heat generated during production. When water is used as a coolant in heat transfer process control, Fixed Flow Rate Orifices offer a reliable method of providing a specific flow through the system.

In OEM applications where the cooling system is internal, known flow data is used to choose the correct FFRO for optimal fluid control for the heat transfer process. With a tamperproof FFRO incorporated into the system, flow characteristics will remain consistent, ensuring the process continually operates as specified.

Water Distribution Systems

aaAll water distribution networks consist of different branches whose flow rates need to be defined at the design stage and must then correspond to the values calculated in the course of operation. In an unbalanced system the flow rate to the circuits nearest the pump is too high, while the flow rate to the circuits furthest from the pump is too low.

Although various valves can be employed to balance the system, an excellent solution to this problem is the Fixed Flow Rate Orifice, which offers unique advantages. The FFRO is designed to provide constant flow even when differential pressure fluctuates. It requires little to no maintenance over its long operating life. 

Fixed Flow Rate Orifices can also be utilized to limit the flow in a water distribution system, saving on water costs. The correct size can be specified for the system which will limit the flow accurately and consistently, and since this tamperproof device is not subject to unwanted adjustments, worry-free water flow limitation is assured.

high-rise apartment buildings

Utilized in a water distibution system such as for high-rise apartments, FFROs keep water flow consistent throughout the building.

high-speed offset web printing of magazines

The optimal, constant water flow rate provided by Fixed Flow Rate Orifices is critical in processes such as offset printing.  

Water Conservation in Industrial Processes

Industrial operations which incorporate water as part of the actual manufacturing process must be very concerned with water utilization and efficiency. The ability to limit water flow rates and keep them constant for these types of processes becomes an economic necessity.

OEMs value the reliable, ready-made solution the Fixed Flow Rate Orifice provides. In applications such as offset printing and sheet plastic production, precise water flow is critical to both the process and the quality of the products. The fact that optimal water flow rate control cannot be tampered with when utilizing Fixed Flow Rate Orifices also offers a definite advantage.

Industrial Heating & Cooling Systems

In heating and cooling system applications, the Fixed Flow Rate Orifice shines in its ability to provide a constant flow rate for the system. It can be difficult to set the optimal flow using an adjustable ball valve, and consistency in flow creates a challenge. Not so for the tamperproof FFRO.

These reliable devices are incorporated into designs by OEMs looking for a simple, virtually maintenance-free method of providing correct flow rates for optimal efficiency in a system. Their flow rate is not affected by changes in differential pressures within their operating range, so process control is set and maintained.

modern large heating & cooling system

Industrial heating and cooling systems can benefit with improved operational efficiency due to the reliable, constant flow rates provided by an FFROs. 

Call us to ask about your Fixed Flow Rate Orifices application: 203.261.6711

Fixed Flow Rate Orifices – Innovative Design, Exceptional Quality

O’Keefe Controls Co. is a world-class manufacturer of precision orifices and fluid control devices, including reliable Fixed Flow Rate Orifices, suitable for many industrial applications. Their innovative, tamperproof  design allows constant water flow regardless of differential pressure increases within their range. 

All products manufactured by O’Keefe Controls Co. pass stringent quality control testing to ensure they operate exactly as specified, with repeatable, consistent performance. With a quality management system that is ISO 9001:2015 registered, all processes are held to the highest standards of quality. 

But perhaps of even greater benefit to our customers, the engineers at O’Keefe Controls Co. are technical experts in the field — knowledgeable about not only our products, but also the science behind their use. As such, we are able to assist customers in diverse practical applications across the industrial, analytical and medical sciences landscape. In all we do, we stand proudly by our tagline: If it’s about precision, it’s O’Keefe.

For assistance finding the Fixed Flow Rate Orifice best suited for your application, Call us: 203.261.6711

Fixed Flow rate orifices

CLICK HERE to view our catalog of Fixed Flow Rate Orifice offerings

For assistance finding the best Fixed Flow Rate Orifice for your application –  Call 203.261.6711