Pressure Control & Flow Regulation

In a fluid handling system, a pump exerts pressure on the fluid in the system to make it flow. Pressure and flow are almost always related in a system. However, factors like viscosity and pressure drop in the system can also impact the pressure-flow relationship. We control fluid pressure to control the flow rate in the system and to meet the requirements for the application quality of an applied material. Several devices exist for controlling fluid pressure in a system, including pulsation dampeners, regulators, back pressure regulators, and pressure relief valves.

Pulsation Dampeners (Surge Tanks, Surge Suppressors)

Surge tanks are the most common type of pulsation dampener. They are frequently used when a customer finds finish quality unacceptable due to pulsation in the spray pattern or when a fluid regulator by itself cannot handle the pulsation. Surge tanks minimize pressure and flow variation, especially that caused by pump changeover. Pump changeover is the point in the cycle of a reciprocating piston pump when the pump stroke changes direction. At that point, the fluid in the pump flows backward momentarily and pressure drops. Surge tanks store both fluid and pressure that is released at that critical point in the pump’s cycle. Air trap surge tanks are used in variety of applications where an acceptable supply of air pressure is available. Gas charged surge tanks are used where air pressure supply is limited and with moisture sensitive materials. They are available in both a piston and a diaphragm design.

Fluid Regulators

Inconsistent pressures in a system can lead to inconsistent material application. Fluid regulators stabilize and control fluid pressure. They are designed to feed material to the application tool at the proper pressure and to maintain pressure balance within a circulating system. Fluid regulators or back pressure fluid regulators can be used to control gun pressure.

A fluid regulator is a self-adjusting valve that senses fluid pressure at the outlet of the regulator and holds it constant. As inlet fluid pressures fluctuate (from pump changeover), fluid regulators modulate to allow more or less fluid flow through the regulator to maintain the set outlet pressure.

It is important to note that, unlike surge tanks and suppressors, fluid regulators can only reduce pressure. The desired outlet pressure must always be lower than the lowest inlet pressure for a fluid regulator to work effectively. Conversely, if the inlet pressure is typically more than 50 percent higher than the desired outlet pressure, the regulator will wear out prematurely.

Diaphragm fluid regulators are used in low to medium pressure applications to allow a quicker response and high sensitivity to pressure changes.

Piston fluid regulators are used in high pressure applications. While they are less sensitive, they are more capable of operating in higher pressure ranges.

Back Pressure Fluid Regulation

Instead of a fluid regulator, a back pressure fluid regulator may be used to stabilize and control the fluid pressure in a system.

A back pressure fluid regulator is a self-adjusting valve that senses the fluid pressure at the inlet of the regulator and holds it constant. As inlet fluid pressures fluctuate, back pressure regulators modulate to allow more or less fluid flow through to maintain the set inlet pressure

Diaphragm back pressure fluid regulators are used in low to medium pressure applications to allow a quicker response and higher sensitivity to pressure changes. Less sensitive, piston back pressure fluid regulators are used in high pressure applications.

Pressure Relief Valves

Pressure relief valves are designed primarily for safety reasons. They protect equipment by venting pressures that exceed a specified level. In a pumping system, this level is usually the maximum working pressure of the lowest rated component in the system.

When pressure rises above a pre-determined pressure, a valve overcomes a spring tension, dumping fluid to relieve the pressure until the system returns to the set pressure.

Both spring loaded valves (which are reloadable) and rupture valves (which must be replaced) are available. Rupture valves are susceptible to false rupture from fatigue on cycling loads such as piston pumps

FLOW METER / VOLUME COUNTERS

Precise monitoring and control of the metering process

The gear flow meter has been developed specifically for use in metering and mixing systems. In processes involving one-part media such as greases, oils and adhesives, it is used for measuring the exact material flow rate at any given moment. The measuring principle is based on the volumetric gear displacement system, characteristic for its accuracy and compressive strength.

The measuring element comprises of a very precisely fitted pair of gears placed in the housing of the flow meter. The rotation of the measuring element is detected by a contactless sensor system and converted into digital signals. A metering unit containing a gear based flow meter combined with a flow-regulating and dispensing valve is ideal for an accurate dispensing or filling of larger quantities of fluids.

Product Features:

• Monitoring and control of metering processes
• Adjustable pulse multiplication up to factor 128 for high measuring resolutions
• Status LED
• Tooth volume 0.04 / 0.1 / 0.2 / 0.4 / 1 / 2 cm
• Cast iron, stainless steel or aluminum design
• Plain or ball bearing version available
• precisely fitted pair of gears placed in the housing of the flow meter. The rotation of the measuring element is detected by a contactless sensor system and converted into digital signals.
• A metering unit containing a gear based flowmeter combined with a flow-regulating and dispensing valve is ideal for an accurate dispensing or filling of larger quantities of fluids.

Options:

• Different connections and adaptors
• Heating
• Connecting cables

ELECTRONICE METERING

Connect and control your metering components

The MR40 is a control unit developed by KIRKCO for the control of complex metering processes. It can be easily integrated into a system with a metering valve or into a 1K metering system with dispensing valves. The control unit enables communication between individual system components and coordinates their operation.

Additionally, the featured software allows users to store numerous metering programes and to recall and run them later. The control unit is equipped with connection ports for various material supply systems and is compatible with monitoring devices such as the gear flow meter or the light barrier. It can be used either as system control or as an interface between a higher level system control and a metering system.

FLOW REGULATING VALVES

Flow Regulating and Control Purpose and Methods

Two factors determine the amount of flow in a system: fluid pressure and the total pressure drop in the system. We control flow in a system to meet the customer’s requirements for the pressure, flow, and application quality. The devices that exist for controlling flow in a system fall into three main categories: on/off valves, adjustable valves, and combination valves.

On/Off Valves

An on/off valve is a flow control device with two operating positions: on and off. The valve may be operated manually, activated by a programmable logic controller (PLC), or meters may be used to measure the volume of fluid and to create a package that turns the valve off after the predetermined volume has been delivered. Several types of on/off valves are used in fluid handling systems, including: ball valves, check valves, solenoid valves, and air-operated valves.

Adjustable Valves

Adjustable valves have an infinite number of operating positions for flexibility in a variety of applications. Pressure and flow are almost always related. Because of this relationship, by controlling flow with an adjustable valve, we also impact system pressure.

Adjustable valves may be adjusted manually by turning a knob or screw, or automatically from a mechanical or electronic controller. This function can be automated with meters and a control device to create a package that adjusts a needle valve to maintain a predetermined flow rate.

Manual Adjustable Valves

By manually turning a screw, you can adjust a tapered needle to slide in and out of the fluid stream. Manual adjustable valves are often used to control the flow rate of fluid in a circulating system. Extrusion guns are manual adjustable valves and are often used to lay a bead of material. For example, spa manufacturers use manual needle valves to extrude adhesive from 5- and 55-gallon containers to lay ceramic tile around portable spas.

Automatic Adjustable Valves

A fluid pressure regulator is one example of an automatic, adjustable valve. A diaphragm or spring is used to adjust the valve. In this case, the flow is adjusted to maintain constant pressure. Or, a material manufacturer may use an automatic needle valve to fill tubes of caulking silicone from a 55-gallon container. In this application, a priming piston pump on a ram with heaters would help the flow of the silicone.

Automatic adjustable valves may also be controlled electronically; the valve position is adjusted by a computer, which also monitors the system flow rate. These type of valves are often used in the robotic application of sealants and adhesives in production lines, such as window glazing and gasketing applications.

Combination Valves

Combination valves can be manually or automatically operated and may be set to be full-on or full-off, or finely adjusted anywhere in between full-on and full-off. One example of combination valves is airspray guns, including high volume low pressure (HVLP) guns and electrostatic guns. Another example is extrusion guns. Window manufacturers use manual extrusion valves to apply caulking material around windows. In automotive assembly plants, automatic extrusion valves apply material that seals the seams between body sheet metal components.

Material Fluid Pressure Regulators

Material pressure regulators reduce the pressure of the pumped material down to the optimum working value. They are designed specifically for the precise dosing of greases, oils and silicones. Along with reducing pressure, the valves also compensate for pulsations that occur when material is delivered via piston pumps, more specifically in the moment of the changeover position of the pump. This problem manifests itself in fluctuations in material pressure and flow, and can lead to reduced product quality - particularly in cases of very small doses, continuous or spray applications. The material pressure regulator is a guarantee of a perfectly stable material flow. For abrasive or reactive material, we recommend our material pressure regulator with a membrane.

MPR with Piston

This type of material pressure regulator is especially suitable for the processing of selflubricating materials such as greases and oils as well as single and plural component silicones. The sealing of the spring space takes place via a slide ring seal.

MPR with diaphragm

This type of material pressure regulator is most suitable for use with reactive, moisture sensitive and, because the ball and seat are manufactured from tungsten carbide, also abrasive media, such as, epoxy resins, polyurethanes and many other materials. The sealing of the spring space takes place via the diaphragm.