What Are Custom Hydraulic Power Units?

HPU for assembling automotive drivelines
Custom HPU's for assembling automotive drivelines
(Process Control Solutions)
There are many manufacturers of standard model hydraulic power units (HPUs), all of which provide an off-the-shelf, readily available, generically configured system. These standard HPUs are a quick and easy solution when hydraulic power is needed. Many times though, standard HPU's don't fit the bill, and a more customized unit is needed. What to do then?

Custom Designed HPUs
Custom manufactured HPUs are hydraulic power solutions designed to fit a customers exact requirement. Customization generally involves the inclusion of special manifolds, cooling fans, level controls, heat exchangers, filtration systems, relief valves, pressure switches and temperature control.

Why Custom?
Certain processes require unique features. A user's proprietary application might require higher pressures, faster response, or continuous operation. While is sounds antithetical, custom HPUs can actually be less expensive than prebuilt, standard model units. This is because custom units are sized and equipped with only the components the application requires. So in actuality, deciding on a custom HPU can potentially lower initial cost and increase profits by improved long-term performance.

Custom hydraulic power units are used in widely in compacting applications, automotive manufacturing equipment, transportation equipment, mining equipment, agricultural equipment, and in many industrial applications.

Vendor Selection
The variety of specialized features for hydraulic power units is endless, making engineering depth and broad application experience very important. Make sure this is proven when interviewing a prospective vendor. The more diversified they are in applying hydraulic power units, the more likely you'll have a positive outcome.

Industrial Butterfly Valves

resilient seated butterfly valve
Resilient seated butterfly valve (Pratt)
Industrial process control valves are available in a very wide array of materials, types, and configurations. The first step of the selection procedure for a valve application should be choosing the valve type, thus narrowing the selection field to a more manageable level. Valve types, ball, butterfly, globe, and plug for example, are generally defined by the closing mechanism of the valve.

high performance butterfly valve
High performance butterfly valve (Pratt)
A butterfly valve uses a  flat disc that is positioned, paddle-like, in the fluid flow path. It rotates around a central axis (the stem) over a 90 degree rotational arc from open (position parallel to the flow direction) to closed (perpendicular to flow). Butterfly valves referred to as resilient seated are generally used in lower pressure, lower temperature applications and create a seal through compressing the disc into some type of elastomer seat. Another type of butterfly valve, used in higher pressure and higher temperature applications, are known as high performance butterfly valves (HPBF). They have highly machined discs and seats which are precisely seated together. Butterfly valve body materials include cast iron, bronze, and stainless steels. It is common to line the butterfly valve with another material to provide special protection from the process media.

Butterfly Valve Advantages:
  • Lower cost
  • Minimal lay length
  • Easy to automate
  • Generally lower torque
Butterfly Valve Disadvantages:
  • High wear rate - seals are in flow paths
  • Not a good choice as a control valve. Has a very nonlinear flow coefficient. 
  • Not great for erosive flowing media.

Butterfly valves, like other valve types, have applications where they outperform. Careful consideration and consultation with a valve expert is a first step toward making a good selection.

Rotary Actuators in Fluid Power Systems

A rotary actuator is an output device for a fluid power system that delivers an oscillating motion over a limited range in less than one full revolution of the circle.

A true rotary actuator produces work by direct action of fluid pressure against internal vanes. Work is defined as a force applied over a distance. Rotary actuators produce a special type of rotational work called torque.

Torque occurs when a force acts on a radius. Since rotary actuators operate at low speed with high torque, torque output rather than the horsepower is used for the rating and identification purposes. Speed is a secondary consideration when choosing a rotary actuator for a particular application.

The typical units of measurement for torque are foot pounds (lb·ft). For example, if a rotary actuator with an arm length or radius of two feet were used to lift the two hundred-pound weight, then the resultant torque required to accomplish the work would be 400 lb·ft.

Understanding the relationship between the output torque required and the physical set up a fluid system enables designers to determine the appropriate rotary actuator for each unique application.

The video below illustrates the mechanics and the physics behind rotary actuators.

Pinch Control Valve for Wash Water Discharge in Treatment Plant

In wastewater treatment plants a pressure control valve is often needed on a standby pump to control discharge of wash water from the wash water pumping station.
Wash Water Discharge
Wash water discharge diagram using pinch control valve (Red Valve
Red Valve Series 5400
Red Valve Series 5400

The main pump and the standby pump are rated to provide maximum flow at a constant pressure. A pressure sensor with integral transmitter is required to continually monitor system pressure. Under normal operating conditions, the pressure control valve is normally closed. After the surface wash shuts down, pressure from the discharge pump changes. The sensed line pressure is transmitted to a controller which sends a signal to the positioner on the control valve.

As the line pressure increases, a Red Valve Series 5400 control pinch valve opens. As the flow demand increases, line pressure decreases, and the valve closes. This system constantly maintains the pressure needed to operate the system. From the pressure control valve, the system discharges to atmospheric pressure over a clear well.

Due to the potentially high pressure drop conditions, the pressure control valve needs to be able to withstand the effects of possible cavitation. Red Valve Series 5400 control pinch valves, with their one-piece elastomer cone sleeve construction, are ideally suited for this application. The flow characteristics and pressure drop capabilities of the cone sleeve controls the flow and handles the pressure drop in the system. To assure cavitation does not occur, a TFO variable orifice to stage the system pressure drop by creating back pressure on the control valve. This setup fulfills the need of the treatment plant, and is a proven cost-effective, maintenance-free solution.

Reprinted with permission from Red Valve.

Electric Valve Actuator with Time-tested Brawn and Sophisticated Control

EIM M2CP actuators were introduced in 1979 as the Series 2000 electric valve actuator. Since that time, the model has added increasingly sophisticated control capabilities—but retained all the mechanical strengths that have established its three decade record of reliability. As a result, many parts can interchange across the entire M2CP/Series 2000 range, and upgrades are remarkably easy to retrofit.

The robust mechanical design of the M2CP is evident in its ductile iron gear case, bronze worm gear, and heat-treated alloy steel worm and modular control packages.

For more information, visit https://flowcontrol.processcontrolsolutions.com/products/suppliers/eim-actuators/ or call (800) 462-5769.

Hy-Lok Instrument Valve and Fitting Fluid Compatibility Guide

Hy-Lok Instrument Valve and Fitting
This guide represents the chemical resistance of the raw materials used to manufacture products by the Hy-Lok Corporation. In general, media characteristics like temperature fluctuation, concentration, high velocity and abrasion will affect corrosion rating. Before applying this guide, many factors that may affect the compatibility ratings should be considered, and users should test under their own operating conditions to determine which materials can be used.

The Fluid Compatibility Guide provides a rating of compatibility of common metals and elastomers to various chemicals and compounds found in industry. The Hy-Lok Corporation Guide contains data assembled from a variety of sources within the metal and chemical industry. However, due to variations in each user application, we do not make any direct or implied warranty as to any specific use or application based upon the performance of any material in this guide. This guide is for reference only and Hy-Lok Corporation is not responsible for the accuracy of the information therein.

For more information on Hy-Lok fittings, visit Process Control Solutions here.

The Piping & Instrumentation Diagram (P&ID)

The Piping & Instrumentation Diagrams (P&ID), or sometimes called Process and Control Flow Diagrams, are schematic representations of a process control system, used to illustrate the piping system, process flow, installed equipment, instrumentation, and functional relationships among all the system components.

They provide information that include component identification how instruments are connected where instruments are located and their function within a process and intended to provide a comprehensive picture of all piping and associated hardware, including physical branches, valves, equipment, instrumentation and interlocks. The P&ID employs a set of standard symbols representing each component of the system such as instruments, piping, motors, pumps, etc. The use of standard symbols provides a universal depiction that can be read and understood by operators, technicians, outside contractors, and other similarly trained individuals.

P&ID’s can be very detailed and are generally the primary source from where instrument and equipment lists are generated, also being a very handy reference for maintenance and upgrades. P&ID diagrams assists technicians when troubleshooting and monitoring specific processes. They also play an important early role in safety planning by enabling an understanding of the operating states and relationships of all components in the system.

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