US6796326B2 - Gas pressure regulator

CROSS-REFERENCE TO RELATED APPLICATION

This application is a National Stage of International Application No. PCT/EP01/, filed Apr. 17, . This application claims the benefit of German Application No. 100 19 049.9, filed Apr. 18, . The disclosures of the above applications are incorporated herein by reference.

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BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a gas pressure regulator for a gas burner as specified in the introductory clause of the first patent claim.

Gas pressure regulators fitted upstream to gas burners are found in a great number of different designs. Gas pressure regulators that are employed in connection with gas burners operated in on-off mode must maintain a constant outlet pressure at a certain gas flow. In some cases such regulator should have an additional pilot burner and/or a lock up. Gas pressure regulators of commonly known design are well suited for such operation mode as they are able to stabilize a pre-set outlet pressure at a constant level within a certain flow range. If the connected gas burner is switched off, the outlet pressure will slightly rise and through a control diaphragm close the control valve in shut position.

Another application is the regulator's employment in connection with a modulating gas burner. Preferably, there are two options available: A first option is to stabilize the outlet pressure at a constant value. This can be done by fitting a flow controlling device&#;for example, a motor-actuated butterfly valve&#;downstream to gas pressure regulator, or by using a zero-pressure regulator to maintain the outlet pressure constantly at zero within a permissible variation. The required gas flow builds up depending on the negative pressure downstream to the burner head. A second option is to allow the outlet pressure to change. This can be achieved, for example, by using a so-called balanced pressure regulator by which the outlet pressure is altered through a control pressure that pressurizes the working diaphragm at its upper face (that is to say the flow is again depending on the outlet pressure), or by using an electronically modulating gas pressure regulator in which regulating is by an electric current&#;or voltage&#;that substitutes for the control pressure.

In either case such gas pressure regulator must be able to feed the gas burner with the correct quantity of gas over the full modulating range, and during the ignition process. Gas pressure regulators have the disadvantage that they&#;especially when operated at small flow rates compared with the maximum permissible flow rate&#;tend to show vibrations or pumping or get stuck in a certain position. This behavior is caused by mechanical friction between the final control elements. If this phenomenon occurs adjusting reproducible outlet pressure or gas flow values will be disabled. In order to enable adjusting reproducible outlet pressure or gas flow values, a bypass opening is usually employed. The disadvantage is that in this solution the gas pressure regulator has no longer any lock up characteristic.

In addition to the above, gas burners that are operated with a large modulation range can very often not get ignited under low-load condition as the quantity of gas available is not sufficient to form an explosive mixture. Usually, the gas burner is therefore fed through a separate gas tube to receive the quantity of gas required for starting. This gas tube, branching off from the gas main, requires an additional solenoid vale that serves as so-called start-load valve, a regulating valve that is either fixed or can be adjusted in order to control the volume flow; and a feeder line to the gas burner.

The most disadvantageous feature in this solution is that a separate gas tube must be laid what is not only expensive but also creates additional space requirements. Furthermore, there are several additional connections the gasproofness of which must be secured to the environment.

There is known another solution in which the start-load valve is fixed to a balanced pressure regulator so that laying of a separate gas tubing is no longer required. The start-load valve is connected to the balanced pressure regulator's casing by two screws. Said screws both have a longitudinal dead-end bore hole and, for the part protruding inside the balanced pressure regulator's casing, a lateral bore hole; they are screwed into the measuring terminals provided at both the input and output side of the balanced pressure regulator, and this way they serve to control the inflow and outflow of gas. Also in this solution, the gas through-flow is cut off by a solenoid valve of known design. An adjustable aperture provides an additional option to control the volume flow.

Also this solution has the disadvantage that there exist several additional connections the gasproofness of which must be secured to the environment. Moreover, the internal pressure drop is rather high due to the fact that the gas stream must be deviated repeatedly. In addition, the high number of pieces entails high manufacturing expenses. Finally, the distance usable for displacements (for making adjustments) is relatively short which causes the setting accuracy to be inadequate.

The invention is focusing on the issue of developing a gas pressure regulator of the said kind in which the disadvantages of the prior art described herein above are eliminated. This applies in particular to the opportunity of having a reproducible outlet pressure, or through flow, maintained throughout the entire regulating range together with the option to keep said lock up characteristic active. Also, gas burners operating with a large modulating range shall be able to get ignited. Furthermore, the internal pressure drop shall be kept as low as possible. Finally, manufacturing expenses and number of gasproof connections shall be kept at a minimum.

According to the present invention the problem is solved by providing one or more separate openings that connect the inlet-side chamber and the outlet-side chamber in addition to the existing passage that is used for pressure regulating purposes, with each of such opening being provided with a seat for a closing body that is individually assigned to said opening and guided in axial direction to its seat, whereat each closing body is connected to the armature of a solenoid valve assigned to it.

Thus a solution has been found that removes the existing disadvantages of the prior art as described herein above. Further distinguishing features of this solution are above all its simplicity and small production dimensions.

The invention comes with an advantageous arrangement if the gas pressure regulator's casing and the solenoid valve's casing are provided in a single-piece design by which the number of gasproof connections can be further reduced.

In addition, the armature's longitudinal length of stroke can be adjusted so that adjusting the volume flow that is required for the ignition of the gas burner becomes easy.

Another advantageous arrangement of the invention results from the replaceable seat construction. Thus, adjustments to different through flow ranges are possible in a simple manner.

Should, for example, the low-load or start-load conditions be within the non-reproducible regulating range as described herein above this phenomenon can be eliminated by employing a gas pressure regulator of this type with the gas pressure regulator's regulating valve being kept in shut position as long as the gas volume is small enough to possibly cause vibrations. If the gas volume is rising toward the required level, the regulating valve will open to such extent that a reliable and vibration-free regulating is allowed.

If the gas burner is ignited under low-load condition, also the lock up characteristic of the gas pressure regulator remains active. This is achieved even when the gas burner is ignited under start-load condition where said start-load is smaller than the low-load and only the low-load is failing within the critical regulating range.

If, in contrast to the above, both start-load and low-load are falling within the critical regulating range use may be made of a gas pressure regulator that has two separate openings that are controlled by two separate solenoid valves. After igniting the gas burner, the second solenoid valve opens to supply the required small-load volume. Even in this case the lock up characteristic of the gas pressure regulator remains active.

The gas pressure regulator's design option with two separate openings, controlled by two separate solenoid valves, is used also in applications where the gas burner is ignited under start-load condition where said start-load is greater than the low-load. For controlling the ignition process the first solenoid valve is switched on and increases the gas quantity until ignition is completed, after which said solenoid valve is closed in shut position. The low-load quantity is supplied through the second solenoid valve, which means that the lock up characteristic of the gas pressure regulator remains active even under such condition.

BRIEF DESCRIPTION OF THE DRAWINGS

Below is a more detailed description of the invention by means of a practical example. The figures show the following:

FIG. 1 is a sectional view of a gas pressure regulator, according to the invention.

FIG. 2 is a sectional view along line A&#;A of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The gas pressure regulator as shown in FIG. 2 as an example according to the invention has a casing (1) made of aluminum, comprising a cover (2), a lower part (3) and a bottom (4). Both cover (2) and lower part (3) as well as lower part (3) and bottom (4) are fixed together by fastening screws. In order to secure the required gasproofness a flat packing (6) is provided between each pair of parts. In addition, between cover (2) and lower part (3) is placed a pressure diaphragm (7), the outer edge of which is clamped between said cover and lower part, with the pressure diaphragm being supported on both sides by an upper diaphragm disk (8) and a lower diaphragm disk (9), respectively, the latter being both arranged in center position.

The cover (2) has of its side away from the lower part (3) a tube-shaped top (10). A pressure piece (11) is screwed-in guided by a thread provided inside said tube-shaped top (10). An adjusting spring (12) rests the pressure piece (11), whereat the spring's opposite end pushes against the upper diaphragm disk (8). A screwed plug (13) is used to seal off the top (10) from the environment. Gasproofness is secured by a gasket (14) placed between the two parts. A vent (15) provided in the cover (2) connects the confined space (16), formed by cover (2) and pressure diaphragm (7), with the environment, or a control pressure (e.g., as built up by a blower).

In the lower part there is a gas inlet (17), which in this practical example is provided with a female thread, connected to the inlet-side chamber (19) formed by a pot-shaped insert (18) that is situated inside the lower part (3) with which it is connected to form one single piece; the inlet-side chamber (19) is sealed toward the cover by a compensating diaphragm (20) the outer edge of which is clamped by a ring (21) pressed into the insert (18). On the insert's (18) face opposite to the compensating diaphragm (20) there is an opening centrally arranged in relation to the ring (21) that is leading into an outlet-side chamber (22) the confined space of which is formed by the lower part (3), the bottom (4) and the insert (18), with said outlet-side chamber (22) in turn being connected to a gas outlet (23) that is situated inside the lower part (3) and also has a female thread. The opening's side facing the bottom (4) is designed as a valve seat (24) to accommodate a valve disk (25) located inside the outlet-side chamber (22), with these parts altogether acting as the gas pressure regulator's pressure regulating valve. Around the gas outlet (23) there is a pressure compensation tubelett (26) that connects the confined space for pressure compensation (27) situated between compensating diaphragm (20) and pressure diaphragm (7) with the outlet-side chamber (22). Underneath the valve disk (25) there is a counter-spring (29) that pushes the valve disk (25) into the valve seat (24) in its resting position.

A hollow shank, that protrudes into the inlet-side chamber (19) and is connected to the valve disk (25) to form one single piece, is fixed on a rod (28) that can be moved in longitudinal direction; said rod (28) goes through the center of the compensating diaphragm (20), that is fixed to the rod, and is guided through the center of the ring (21). The rod's (28) ends far from the valve disk (25) are centrally fixed to either the upper and the lower diaphragm disk (8 & 9). In order to limit the opening stroke length, the ring (21) serves as limit stop to the lower diaphragm disk (9).

As can be seen from FIG. 1, a guide bush (30) is screwed gas-tight into the lower part's (3) outer surface shell; the first part of said guide bush (30) goes through the wall and is designed to hold a electro-magnetic drive as described herein below in more detail. Inside said guide bush (30) there is an armature (31) that together with a coil (32) arranged on the guide bush (30) forms an electromagnetic drive, the movement of which is guided in longitudinal direction. The armature's (31) end that protrudes inside the outlet-side chamber (22) is designed as closing body (33), in this practical example having the form of a closing cone. Extended in the armature's (31) axial direction, the insert (18) has an opening (34) that connects the inlet-side chamber (19) with the outlet-side chamber (22), and that serves as seat (35) for the closing body (33). Seat (35) and closing body (33) together form the so-called start-load valve (36). As a further advantageous arrangement, interchangeable sleeves (not shown) can be placed inside the opening (34), with each such sleeve standing for a different opening cross-section of the seat (35).

On its side opposite to the closing body (33), the armature (31) has a necking (37) on which is guided a closing spring (38) that exercises pressure on said armature (31) so that the closing body (33) rests in its seat (35) and the start-load valve (36) keeps in closed position even under maximum inlet pressure in the inlet-side chamber (19). In order to achieve this, the closing spring's (38) other end rests on a shoulder (39) formed by the second part of the guide bush (30) that is screwed into the first part and gas-tight glued-in. The face side of an adjusting screw (40) that is screwed-in and guided into the guide bush's (30) second part serves as limit stop to limit the armature's (31) opening stroke length. In order to secure the required tightness, the adjusting screw (40) is provided with a circumferential groove in which an O-ring seal (41) is placed. In order to protect the adjusting screw (40), the guide bush (30) is sealed-off by a screw cap (42) that at the same time serves to fix the coil (32) in its position.

The function of the balanced pressure regulator according to the invention described in this practical example is as follows:

The start-load valve (36) and the pressure regulating valve will be in their closed positions if the gas burner (not shown), connected downstream to the gas pressure regulator according to the invention, is out of operation. An explosive mixture is required in order to put the gas burner into operation. To supply the gas volume required for that purpose, coil (32) is electrically triggered. As a results of this, the armature (31), counteracting the closing spring's (38) force, is pushed down to its limit stop against the adjusting screw (40) whereby the start-load valve (36) opens (FIG. 1). The adjusting screw (40) can be used to pre-set the required opening stroke length, i.e. the gas volume needed. Such adjustment can be made very precisely, in particular due to the fine-pitch thread provided. Even an adjustment to limit the stroke length to a &#;zero&#; value is possible. After ignition of the gas burner is completed, the electric triggering of coil (32) is stopped, and the closing body (33) is forced by the closing spring (38) back into its seat (35). Depending on the load of the adjusting spring (12) pre-set through the pressure piece (11) and the control pressure that is now being switched on, the outlet pressure of the gas flowing to the gas burner (such pressure being equal to the pressure built up in the outlet-side chamber (22)) is controlled and kept at a constant level in a manner as is well known (FIG. 2).

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Pressure Regulators are found in many common home and industrial applications. For example, pressure regulators are used in gas grills to regulate propane, in home heating furnaces to regulate natural gases, in medical and dental equipment to regulate oxygen and anesthesia gases, in pneumatic automation systems to regulate compressed air, in engines to regulate fuel and in fuel cells to regulate hydrogen. As this partial list demonstrates there are numerous applications for regulators yet, in each of them, the pressure regulator provides the same function. Pressure regulators reduce a supply (or inlet) pressure to a lower outlet pressure and work to maintain this outlet pressure despite fluctuations in the inlet pressure. The reduction of the inlet pressure to a lower outlet pressure is the key characteristic of pressure regulators.

When choosing a pressure regulator many factors must be considered. Important considerations include: operating pressure ranges for the inlet and outlet, flow requirements, the fluid (Is it a gas, a liquid, toxic, or flammable?), expected operating temperature range, material selection for the regulator components including seals, as well as size and weight constraints.

Materials used in pressure regulators

A wide range of materials are available to handle various fluids and operating environments. Common regulator component materials include brass, plastic, and aluminum. Various grades of stainless steel (such as 303, 304, and 316) are available too. Springs used inside the regulator are typically made of music wire (carbon steel) or stainless steel.

Brass is suited to most common applications and is usually economical. Aluminum is often specified when weight is a consideration. Plastic is considered when low cost is of primarily concern or a throw away item is required. Stainless Steels are often chosen for use with corrosive fluids, use in corrosive environments, when cleanliness of the fluid is a consideration or when the operating temperatures will be high.

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Equally important is the compatibility of the seal material with the fluid and with the operating temperature range. Buna-n is a typical seal material. Optional seals are offered by some manufacturers and these include: Fluorocarbon, EPDM, Silicone, and Perfluoroelastomer.  

Fluid Used (gas, liquid, toxic, or flammable)

The chemical properties of the fluid should be considered before determining the best materials for your application. Each fluid will have its own unique characteristics so care must be taken to select the appropriate body and seal materials that will come in contact with fluid. The parts of the regulator in contact with the fluid are known as the &#;wetted&#; components.

It is also important to determine if the fluid is flammable, toxic, explosive, or hazardous in nature. A non-relieving regulator is preferred for use with hazardous, explosive, or expensive gases because the design does not vent excessive downstream pressure into the atmosphere. In contrast to a non-relieving regulator, a relieving (also known as self-relieving) regulator is designed to vent excess downstream pressure to atmosphere. Typically there is a vent hole in the side of the regulator body for this purpose. In some special designs, the vent port can be threaded and any excess pressure can be vented from the regulator body through tubing and exhausted in a safe area. If this type of design is selected the excess fluid should be vented appropriately and in accordance to all safety regulations. 

Temperature

The materials selected for the pressure regulator not only need to be compatible with the fluid but also must be able to function properly at the expected operating temperature. The primary concern is whether or not the elastomer chosen will function properly throughout the expected temperature range. Additionally, the operating temperature may affect flow capacity and/or the spring rate in extreme applications.

Operating Pressures

The inlet and outlet pressures are important factors to consider before choosing the best regulator. Important questions to answer are: What is the range of fluctuation in the inlet pressure? What is the required outlet pressure? What is the allowable variation in outlet pressure?

Flow Requirements

What is the maximum flow rate that the application requires? How much does the flow rate vary? Porting requirements are also an important consideration.

Size & Weight

In many high technology applications space is limited and weight is a factor. Some manufactures specialize in miniature components and should be consulted if overall size and weight are critical.  Material selection, particularly the regulator body components, will impact weight. Also carefully consider the port (thread) sizes, adjustment styles, and mounting options as these will influence size and weight.

Pressure Regulators in Operation

A pressure regulator is comprised of three functional elements

1. ) A pressure reducing or restrictive element. Often this is a spring loaded poppet valve.
2. ) A sensing element.  Typically a diaphragm or piston.
3. ) A reference force element.  Most commonly a spring. 

In operation, the reference force generated by the spring opens the valve. The opening of the valve applies pressure to the sensing element which in turn closes the valve until it is open just enough to maintain the set pressure. The simplified schematic &#;Pressure Regulator Schematic&#; illustrates this force balance arrangement. (see below)

(1) Pressure Reducing Element (poppet valve)

Most commonly, regulators employ a spring loaded &#;poppet&#; valve as a restrictive element.   The poppet includes an elastomeric seal or, in some high pressure designs a thermoplastic seal, which is configured to make a seal on a valve seat.  When the spring force moves the seal away from the valve seat, fluid is allowed to flow from the inlet of the regulator to the outlet.  As the outlet pressure rises, the force generated by the sensing element resists the force of the spring and the valve is closed. These two forces reach a balance point at the set point of the pressure regulator. When the downstream pressure drops below the set-point, the spring pushes the poppet away from the valve seat and additional fluid is allowed to flow from the inlet to the outlet until the force balance is restored.

(2) Sensing Element (piston or diaphragm)

Piston style designs are often used when higher outlet pressures are required, when ruggedness is a concern or when the outlet pressure does not have to be held to a tight tolerance. Piston designs tend to be sluggish, as compared to diaphragm designs, because of the friction between the piston seal and the regulator body.

In low pressure applications, or when high accuracy is required, the diaphragm style is preferred.  Diaphragm regulators employ a thin disc shaped element which is used to sense pressure changes. They are usually made of an elastomer, however, thin convoluted metal is used in special applications.  Diaphragms essentially eliminate the friction inherent with piston style designs. Additionally, for a particular regulator size, it is often possible to provide a greater sensing area with a diaphragm design than would be feasible if a piston style design was employed.

(3) The Reference Force Element (spring)

The reference force element is usually a mechanical spring.  This spring exerts a force on the sensing element and acts to open the valve.  Most regulators are designed with an adjustment which allows the user to adjust the outlet pressure set-point by changing the force exerted by the reference spring.

Regulator Accuracy and Capacity

The accuracy of a pressure regulator is determined by charting outlet pressure versus flow rate.  The resulting graph shows the drop in outlet pressure as the flow rate increases. This phenomenon is known as droop. Pressure regulator accuracy is defined as how much droop the device exhibits over a range of flows; less droop equals greater accuracy. The pressure versus flow curves provided in the graph &#;Direct Acting Pressure Regulator Operating Map&#;, indicates the useful regulating capacity of the regulator.  When selecting a regulator, engineers should examine pressure versus flow curves to ensure the regulator can meet the performance requirements necessary for the proposed application.

Droop Definition

The term &#;droop&#; is used to describe the drop in the outlet pressure, below the original set-point, as flow increases. Droop can also be caused by significant changes in the inlet pressure (from the value when the regulator output was set). As the inlet pressure rises from the initial setting, the outlet pressure falls. Conversely, as the inlet pressure falls, the outlet pressure rises. As seen in the graph &#;Direct Acting Pressure Regulator Operating Map&#;, this effect is important to a user because it shows the useful regulating capacity of a regulator.

Orifice Size

Increasing the valve orifice can increase the flow capacity of the regulator. This may be beneficial if your design can accommodate a bigger regulator however be careful not to over specify. A regulator with an oversized valve, for the conditions of the intended application, will result in a greater sensitivity to fluctuating inlet pressures, and may cause excessive droop.

Lock Up Pressure

&#;Lockup pressure&#; is the pressure above the set-point that is required to completely shut the regulator valve off and insure that there is no flow.

Hysteresis

Hysteresis can occur in mechanical systems, such as pressure regulators, due to friction forces caused by springs and seals. Take a look at the graph and you will notice, for a given flow rate, that the outlet pressure will be higher with decreasing flow than it will be with increasing flow.

Single-Stage Regulator

Single-stage regulators are an excellent choice for relatively small reductions in pressure. For example, the air compressors used in most factories generate maximum pressures in the 100 to 150 psi range. This pressure is piped through the factory but is often reduced with a single-stage regulator to lower pressures (10 psi, 50 psi, 80 psi etc.) to operate automated machinery, test stands, machine tools, leak test equipment, linear actuators, and other devices. Single stage pressure regulators typically do not perform well with large swings in inlet pressure and/or flow rates.

Two-Stage (Dual Stage) Regulator

A two-stage pressure regulator is ideal for applications with large variations in the flow rate, significant fluctuations in the inlet pressure, or decreasing inlet pressure such as occurs with gas supplied from a small storage tank or gas cylinder.

With most single-stage regulator regulators, except those that use a pressure compensated design, a large drop in inlet pressure will cause a slight increase in outlet pressure.  This happens because the forces acting on the valve change, due to the large drop in pressure, from when the outlet pressure was initially set.  In a two-stage design the second stage will not be subjected to these large changes in inlet pressure, only the slight change from the outlet of the first stage.  This arrangement results in a stable outlet pressure from the second stage despite the significant changes in pressure supplied to the first stage.

Three-Stage Regulator

A three-stage regulator provides a stable outlet pressure similar to a two-stage regulator but with the added ability to handle a significantly higher maximum inlet pressure. For example, the Beswick PRD4HP series three-stage regulator is rated to handle an inlet pressure as high as 3,000 psi and it will provide a stable outlet pressure (in the 0 to 30 psi range) despite changes to the supply pressure.   A small and lightweight pressure regulator that can maintain a stable low output pressure despite an inlet pressure that will decrease over time from a high pressure is a critical component in many designs.  Examples include portable analytical instruments, hydrogen fuel cells, UAVs, and medical devices powered by high pressure gas supplied from a gas cartridge or storage cylinder.

Now that you have chosen the regulator that best suits your application it is important that the regulator is installed and adjusted properly to insure that it functions as intended.  

Most manufacturers recommend the installation of a filter upstream of the regulator (some regulators have a built-in filter) to prevent dirt and particulates from contaminating the valve seat.  Operation of a regulator without a filter could result in a leaking to the outlet port if the valve seat is contaminated with dirt or foreign material.   Regulated gases should be free from oils, greases, and other contaminants which could foul or damage the valve components or attack the regulator seals.  Many users are unaware that gases supplied in cylinders and small gas cartridges can contain traces of oils from the manufacturing process.   The presence of oil in the gas is often not apparent to the user and therefore this topic should be discussed with your gas supplier before you select the seal materials for your regulator.  Additionally, gasses should be free of excessive moisture. In high flow rate applications, icing of the regulator can occur if moisture is present.

If the pressure regulator will be used with oxygen, be aware that that oxygen requires specialized knowledge for safe system design. Oxygen compatible lubricants must be specified and extra cleaning, to remove traces of petroleum based cutting oils, is typically specified.  Make certain that you inform your regulator supplier that you plan to use the regulator in an oxygen application.

Do not connect regulators to a supply source with a maximum pressure greater than the rated inlet pressure of the regulator.  Pressure regulators are not intended to be used as shutoff devices.  When the regulator is not in use, the supply pressure should be turned off. 

Installation

STEP 1
Begin by connecting the pressure source to the inlet port and the regulated pressure line to the outlet port. If the ports are not marked, check with the manufacturer to avoid incorrect connections. In some designs, damage can occur to the internal components if the supply pressure is mistakenly supplied to the outlet port.

STEP 2
Before turning on the supply pressure to the regulator, back off the adjustment control knob to restrict flow through the regulator.  Gradually turn on the supply pressure so as not to &#;shock&#; the regulator with a sudden rush of pressurized fluid. NOTE: Avoid turning the adjustment screw all the way into the regulator because, in some regulator designs, the full supply pressure will be delivered to the outlet port.

STEP 3
Set the pressure regulator to the desired outlet pressure.  If the regulator is non-relieving, it will be easier to adjust the outlet pressure if fluid is flowing rather than &#;dead ended&#; (no flow).  If the measured outlet pressure exceeds the desired outlet pressure, vent the fluid from the downstream side of the regulator and lower the outlet pressure by turning the adjustment knob. Never vent fluid by loosening fittings, as injury may result.

With a relieving style regulator, excess pressure will be automatically vented to atmosphere from the downstream side of the regulator when the knob is rotated to lower the output setting. For this reason, do not use relieving style regulators with flammable or hazardous fluids.  Be sure the excess fluid is vented safely and in accordance with all local, state and federal regulations.

STEP 4
To obtain the desired outlet pressure, make the final adjustments by slowly increasing the pressure from below the desired set point. Setting the pressure from below the desired setting is preferred to setting it from above the desired setting.  If you overshoot the set point while setting the pressure regulator, back off the set pressure to a point below the set point.  Then, again, gradually increase the pressure to the desired set point.

STEP 5
Cycle the supply pressure on and off several times while monitoring the outlet pressure to confirm the regulator is consistently returning to the set point. Additionally, the outlet pressure should also be cycled on and off to ensure the pressure regulator returns to the desired set point.  Repeat the pressure setting sequence if the outlet pressure does not return to the desired setting. 

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