WO1988005159A1

WO1988005159A1 - High pressure flow controller and flowmeter device

Info

Publication number: WO1988005159A1
Application number: PCT/US1988/000063
Authority: WO
Inventors: Mike S. Shelton
Original assignee: Skoglund, Paul, K.; Briske, Gerald
Priority date: 1987-01-08
Filing date: 1988-01-05
Publication date: 1988-07-14
Also published as: AU1221688A

Abstract

A flow control and flowmeter device has been invented whereby both flow control and flowmetering can be achieved over a wide range of flowrates and pressures. Both accurate flow control and flowmetering are supported substantially free from error due to upstream and downstream pressure fluctuations. Additional features include external flowrate indication (104) and a direct rate adjustment whereby the entire flowrate range is encompassed within a single turn of the flowrate adjustment shaft (62). A pointer (74) is attached to the flowrate adjustment shaft (62) thereby making direct rate setting possible. Innovative spring system (40, 42, 48, 53) and seal designs (60, 68) result in accurate and repeatable flowrate adjustment. The reduction in operating time, the wide range of flowrates and pressures and the accuracy of the device make it attractive in many applications.

Description

Description HIGH PRESSURE FLOW CONTROLLER AND FLOWMETER DEVICE

Background of the Invention

The present invention relates to a single high or low pressure flow controller/flow meter device applicable in all phases of Newtonian fluid metering and/or flow control.

Flow control and metering occurs substantially independent of upstream or downstream pressure fluctuations.

Currently, metering or fluid flow control is, by and large, supported by the application of metering pumps or differential pressure controllers (regulators), used in conjunction with metering valves. All of the above methods require either expensive metering systems or external calibration systems with associated trial and error flowrate adjustment procedures. Most of the above methods are also unable to accurately control and meter fluid below rates of 0.5 gallons per day. The need for a high pressure flow control system possessing the capability of direct rate adjustment and a flowmetering capability applicable to all flowrates inherent within the system was noted. The present invention embodies a solution to such a need.

Statement of the Invention

With reference to all of the foreseeable present and future industry flow control/metering requirements, the primary objectives of this invention are to provide:

1) An extremely accurate flow control device capable of high and low pressure discharge with high and low rate capacity.

2) An accurate flow control/metering device substantially unaffected by upstream or downstream pressure fluctuations. 3) A flow control device featuring a direct flowrate adjustment capability via a mechanical pointer and flowrate scale supporting immediate and simple flowrate setting.

4) A flowmeter embodied within the flow control device, forming one unit, capable of accurately indicating flowrate of subject invention over subject invention flowrate range.

5) A flow control device that would require no extraneous mounting equipment, but rather would be secured directly into process piping via the pipe threaded structural design.

6) A flow control device/flowmeter capable of controlling and metering the flow of all Newtonian fluids and all gases under 10,000 centistokes viscosity. 7) A flow control device/flowmeter that could achieve all of the above without requiring electrical, pneumatic or hydraulic power sources.

8) A flow control/flowmeter device supporting above objectives with a minimum of moving parts and the associated wear.

Other objectives and advantages of the present invention may be more fully understood by reference to the following description of operational aspects of the present invention including the following drawings.

Brief Description of the Drawings

Fig. 1 is a perspective of the device showing the flow rate indicator (front) and the flow rate adjustment mechanism (top) as it will be provided to industry;

Fig. 2 is a front elevational view of the flowrate meter;

Fig. 3 is a cross-section view taken on lines 3-3 of Fig. 2;

Fig. 4 is a cross-section view taken on line 4-4 of Fig. 3; Fig. 5 is a cross-section view taken on line 5-5 of Fig. 2.

Detailed Description of the Invention

Operational sequence can be understood with reference to Figs. 3, 4, and 5. All components of the subject invention are contained within a single housing 10. Inlet pressure (P_in) is introduced via Pressure Ports 12 or 14. Pressure is simultaneously transmitted to the flowmeter portion of the device via Pressure Port 16. No flow occurs through Pressure Port 16 during normal operation. Inlet pressure (P_in) works against the flowmeter Piston Seal 18 and displaces the Flowmeter Piston 20/Flowmeter Primary Magnet 22 against the Flowmeter End Plug 24. The Flowmeter Piston 20/Flowmeter Primary Magnet 22 will remain in this position until pressure stabilization occurs within the flow control portion (Chamber 26 and Chamber 28) Fig. 5 of the device, (via Pressure Port 30).

Flow induced by inlet pressure (P_in) occurs through Pressure Port 32 and passes through a properly sized Particle Screen 34, Fig. 5. Fluid flow continues from the Particle Screen 34 via Pressure Port 36 and through the first Orifice/Orifice System 38. Flow induced differential presure across the Orifice/Orifice system 38 is used to meter flow rate. The flowmeter, although previously mentioned, will be described in length later.

By properly sizing a single orifice or grouping many very small orifices together (orifice system), a specially designed prssure drop can be achieved for a specified flow rate. Flow continues into Chamber 26 which houses two Ball Bearings 40 and two Bellville Washers 42. Flow into Chamber 26 initiates a pressure increase therein resulting in fluid flow into Pressure Port 44 and through the Orifice/Orifice System 46. Pressure continues to build in Chamber 26 due to greater flow rate through the first Orifice/Orifice System 38 than that through the second Orifice/Orifice System 46. This greater flow rate through Orifice/Orifice System 38 is supported by both Orifice/Orifice Systems 38 and 46 design and greater differential pressure across Orifice/Orifice System 38. For the subject invention to operate and sustain smooth start-up, the Orifice/Orifice System 38 relationship to Orifice/Orifice System 46 can be shown to be

CV_10RF ≥ CV_20RF (Equation 1)

Where

CV_10RF = Flow Capacity of the first Orifice/Orifice System

CV_20RF = F^ow Capacity of the secondOrifice/Orifice System P_1C = pressure in Chamber 26

P_2C = Pressure in Chamber 28

P_in = Inlet Pressure to the Invention

If Equation 1 parameters are satisfied, the subject invention will start up and operate properly. Equation 1 parameters are the only restrictions on the flow capacity design of the Orifice/Orifice Systems 38 and 46 for a given flowrate range.

The above described increase in pressure within Chamber 26 compresses the lower set of Bellville Washers 48 and thereby drives the Flow Control Piston 50 down, seating the Flow Control Pin 52 and Spring 53 into the Flow Control Seat 54. The Flow Control Seat 54 effectively seals Chamber 28 with the resultant increase of pressure. As pressure continues to build in Chamber 28 due to the Flow Control Seat 54 and Flow Control Pin 52 flow blockage, a point is reached when the Chamber 28 pressure exceeds that necessary in conjunction with the Bellville Washer 48 to lift the Flow Control Piston 50. As the Flow Control Piston 50 lifts, the Flow Control Pin 52 is slightly unseated from the Flow Control Seat 54. Flow is then initiated through the Flow Control Seat 54 and through the Pressure Port 56 and through the Protective Check Valve 58. The Flow Control Piston 50 rises to a position whereby the Flow Control Pin 52 is exactly the proper distance from the Flow Control Seat 54 to provide the required flow restriction to balance the Flow Control Piston 50 and support the resulting flowrate.

Assuming unloaded Ball Bearings 40 and unloaded Bellville Washers 42, the force balance on the Flow Control Piston 50 can be described as follows:

P(A_FCP) = P(A_FCP) + F_BW48 (Equation 2) Following through and solving for (P₂₆-p₂₈)

(P₂₆ -P₂₈) ⁼ (Equation 3)

Where

P₂₆ = Pressure in Chamber 26 (P_in - P_10RF)

P₂₈ = Pressure in Chamber 28

A_FCP ⁼ Area of the Flow Control Piston 50. (In reality, area of Flow Control Piston Seal 60 outside diameter.) F _BW48 = Force Exerted by Bellville Washers 48 at point where Flow Control Piston 50 is in a position where the Flow Control Pin 52 is in near contact with Flow Control Seat 54, (i.e., balanced forces). However, (P₂₆ - P₂₈) is the differential pressure across Orifice/Orifice System 46. Applying the flow equation yields:

Q = CV Δp/SG (Equation 4) Substituting

Q CV₄₆ \ F BW48 /(A_FCP *SG) (Equation 5)

Where

Q = Flow Rate

CV₄₆ = Flow capacity of Orifice/Orifice System 46

Δ P = P₂₆ - P₂₈ SG = Specific gravity of fluid From Equation 5 it can be seen that the flowrate is only a function of the Bellvile Washer 48 spring force and is substantially unaffected by upstream (P_2g) ^or downstream (pressure in Pressure Port 56) fluctuations.

Without the Ball Bearings 40/Bellville Washer 42/Flow Adjustment Shaft 62 flowrate adjustment system, flowrates from the subject invention cannot be adjusted as is obvious from Equation 5. The force from the Bellville Washer 48 is fixed by the length of the Flow Control Piston Shaft 64. This length determines how far the Flow Control Piston 50 must travel to seat the Flow Control Pin 52 into the Flow Control Seat 54 and hence, the load and subsequent force of the Bellville Washers 48. A special note should be interjected here concerning friction and other forces neglected in the development of Equation 2. These forces affect the accuracy of the subject invention and should be addressed. Friction forces on Flow Control Piston Seal 60 have been reduced through the application of a specially designed graphite/TFE seal. A Flow Control Piston Graphite Sleeve 66 has been added between the bore 68 and Flow Control Piston 50 within a groove 70 provided in the Flow Control Piston 50.

Another adverse force originates from a differential pressure across the Flow Control Pin 52 and the Flow Control Seat 54 interface. A force reduction has been achieved within the invention by designing the Flow Control Piston 50 diameter to be much larger than the Flow Control Pin 52/Flow Control Seat 54 interface diameter. Hence, Equation 2, properly describes the process.

To increase the usefulness of the device, a flowrate adjustment mechanism is thereby required. This requirement is met with the following components: 1. Two Ball Bearings 40 2 . Two Bellville Washers 42 3. Flow Adjustment Shaft 62

4. Flowrate Indicator Sleeve 72

5. Flowrate Indictor Pointer 74

6. Flowrate Indicator Rate Scale 76 7. Flowrate Indicator Zero Adjustment Screw 78

8. Flowrate Adjustment Handle 80 This novel approach to flowrate adjustment can once again be better understood via considerationinfurther detail of the force balance on the Flow Contgrol Piston 50. Referring to Equation 2:

P₂₆A_FCP ⁼ P₂₈A_FCP + F_BW48 However, Equation 2 is valid only when the Bellville Washers

42 and Ball Bearing 40 are not loaded.

Flowrate adjustment occurs by loading the Bellville Washers 42 and the Ball Bearings 40 with the Flow Adjustment

Shaft 62.

The force exerted by the Flow Adjustment Shaft 62 on the Flow Control Piston 50 via the Bellville Washers, 42 and the Ball Bearings 40 is: F_FAS = K_BW42 X_FAS

Where

F_FAS = Force exerted by Flow Adjustment Shaft 62 on the Bellville Washers 42 and the Ball Bearing

40 and hence on the Flow Control Piston 50. K_BW42 = Force Per distance travel of Bellville Washers

42. This value is not necessarily a constant and for Bellville Washer 42 is a function (non-linear). X_FAS = Distance traveled by Flow Adjustment Shaft 62, i.e., number of turns divided by number of threads per inch.

Hence,

F_FAS = K_BW42 L (Equation 7)

= K_BW42 (Equation 8)

Where

= Number of degrees in which the Flow Adjustment Shaft 62 is rotated inward during flowrate adjustment cycle N = Number of threads per inch in the designed thread pattern for the Flow Adjustment Shaft 62. Adding the force exerted by the Flow Adjustment Shaft 62 (Equation 8) to Equation 2 yields: P₂₆ (A_FCP) + F_FAS = P₂₈(A_FCP) + F_BW48 (Equation 9) P₂₆ (A_FCP) + ^KB_W42 = θ ^{= P}28 (A_FCP) + ^FBW48 (Eq.10)

Combining terms and solving for (P₂₆ - P₂₈) yields:

P_26(AFCP) - P₂₈(A_FCP) = F_BW48 - K_BW42 (Equation 11)

(P₂₆ - P₂₈) = (Equation 12)

Once again, (P₂₆ - P₂₈) is the differential pressure across the Orifice/Orifice System 46. Thereby, substituting Equation 12 into Equation 4 yields:

Q = CV₄₆

From Equation 13 it can be seen that the flowrate Q can be varied simply by rotating the Flow Adjustment Shaft 62 through a given O.

Both F_BW50 and K_BW42 can then be designed such that Q varies 0 to 100% over the Flow Adjustment Shaft 62 rotation range 0< 0< 360, (one turn) providing a flowrate adjustment that can be indicted externally with the Flowrate Indicator Sleeve 72, Flowrate Indicator Pin 74 and the Flowrate Indicator Scale 76, (in appropriate volumetric units per time such as gallons per day, quarts per minute, etc.). For the above direct flowrate adjustment capability to be useful, the invention must evidence repeatability at each Flowrate Indicator Pin 74 and Flowrate Indicator Scale 76 setting. With the normal Bellville Washer 82 configuration (see Fig. 6), consisting of a given number of Bellville Washers 82 with an internal 84 or external 86 (or both) guide 88 whereby compression can occur, unacceptable friction between the Bellwville Washers 82 and the guide 90 causes error and reduces invention repeatability.

Another problem affecting repeatability occurs due to the rotating motion of the Flow Adjustment Shaft 62 during force transfer to the Flow Control Piston 50. The rotational transfer of force from the Flow Adjustment Shaft 62 would tend to rotate the Bellville Washers 42, the Flow Control Piston 50, the Flow Control Piston Shaft 64, and the lower Bellville Washers 48. This continual realignment and rotational shifting of components would result in a significant loss of repeatability.

To achieve repeatability, two Ball Bearings 40 were implemented in conjunction with two Bellville Washers 42, to provide a virtually (rotationally and axially) friction-free spring which allowed desirable, repeatable operation of the operation of the subject invention.

The virtually friction-free spring is contained in Chamber 26. A small notch 92 is provided in the bottom of the Flow Adjustment Shaft 62 (contacting area), whereby the top Ball Bearing 40 is centered. This small area of contact between the Flow Adjustment Shaft 62 and the top Ball Bearing 40 results in minimum rotational friction force transfer. Additionally, the top Ball Bearing 40 centers the top Bellville Washer 42 such that it is not in contact with the bore wall 94 and, likewise has no guide through it. The Flow Control Piston 50 has a large notch 96 out in its top. The bottom Ball Bearing 40 is thus centered by resting in this notch 96 and in turn centers the bottom Bellville Washer 42 such that it exactly meets the upper Bellville Washer 42 which has neither internal nor external guides upon which frictional forces may act. The result is a novel spring design that reduces rotational friction and virturally eliminates axial friction.

To provide flowrate indication, a novel flowmetering capability has been added inherent in the single unit configuration of the invention. The device has a single flow stream through it which has been shown to be controlled by varying the differential pressure across the second Orifice/Orifice System 44 via the loading and unloading of one of two opposing Bellville Washers (42 and 48), spring systems with a revolving Flow Adjustment Shaft 62.

By installing another very low capacity Orifice/Orifice System 38 within the flow stream (as referenced earlier), and monitoring the induced differential pressure, flowrate can be metered and indicated. This differential pressure is monitored and indicated by the following components within the invention:

1. Flow Controller. Top 1 Housing the Orifice/Orifice System 38.

2. Flow Meter Piston Magnet 22 3. Flow Meter Piston Seal 18

4. Flow Meter Piston 20

5. Flow Meter Differential Pressure Spring 21

6. Flow Meter End Plug 24

7. Pressure Port 16 8. Pressure Port 30

9. Flow Meter Rotary Magnet 100

10. Flow Meter Rate Scale 102

11. Indicating Needle 104

12. Gauge Housing 106 As previously mentioned, during start-up or initial pressurizing of the invention, pressure is transmitted to the Flowmeter Piston 20 and Flow Meter Piston Seal 18 via Pressure Bore 16 resulting in full compression of the Flowmeter Piston Differential Pressure Spring 21. The resultant Flowmeter Piston 20 position is maintained until flowrate through the Orifice/Orifice System 38 decreases, i.e., flowrate through Orifice/Orifice System 46 begins to stabilize. At this point, pressure has increased in Chamber 26. This pressure increase is transmitted to the Flowmeter Piston 20 (side opposite Pressure Bore 16).

Close inspection of Fig. 3 and 4 will show that pressure upstream of Orifice/Orifice System 38 is transmitted to the Flowmeter Piston 20 via Pressure Bores 15 and 16. Pressure downstream of Orifice/Orifice System 38 is transmitted via Chamber 26 and Pressure Bore 30 to the opposite side of the Flowmeter Piston 20. The two pressure areas are separated by 'O' Ring 108. The Flowmeter Piston 20 position is affected by the differential pressure of these two areas (across Orifice/Orifice System 38). Proper design of the Flowmeter Piston Differential Pressure Spring 21 and the flow capacity of Orifice/Orifice System 38 per a specified flowrate will yield a range of positions for the Flowmeter Piston 20 which can be used to accurately indicate the flowrate through the invention. To indicate the flowrate, the position of the Flowmeter Piston 20 and Flowmeter Primary Magnet 22 must be externally known. This position can be displayed externally by placing a Rotary Magnet 100 in close proximity to the Flowmeter Primary Magnet 22. The flowmeter Rotary Magnet 100 has a radially (rather than axially) induced magnetic field. As the flowmeter Primary Magnet 22 in the. adjacent bore travels past the Flowmeter Rotary Magnet 100, rotation is induced in the Flowmeter Rotary Magnet 100. A Flowmeter Indicating Needle 104 is attached to the Flowmeter Rotary Magnet 100, under the Flowmeter Indicating Needle 104 and above the Flowmeter Rotary Magnet 100 is place a Flowmeter Rate Scale 102 whereby flowrate determination is made.

Special notice should also be given to other features designed into the unit. The End Cap 110 has been designed utilizing an external National Pipe Thread 112 to facilitate installation directly into a tapped blind flange or thread- o-let, thus eliminating the need for mounting equipment.

Also within the external NPT Threaded End 112 is an internal NPT Threaded Bore 114 which provides for the installation of a Flow Extension 116 which supports improved fluid delivery into the intended process stream, shown in phantom Fig. 1.

Since the invention may support extremely low flowrate control, any leakage across the Flow Control Pin 52 and Flow Control Seat 54 is unacceptable. Even though extremely fine surface finishes are employed in these areas, small leakage still occurs due to micro-crevices remaining from the manufacturing process. To fill and seal these crevices while improving erosion resistance properties of the material, both (8/10) are coated with Titanium Nitride. This novel application of a hardened coating normally applied to tooling steels results in a positive shut-off and extended product life.

The Flow Controller/Flowmeter device of this invention can readily be constructed from components available from vendors. Some of the vendors for several components utilized are provided in the following table:

VENDOR PRODUCT REF. NO.

BalSeal Engineering Co. Flow Control Piston 60 620 W. Warner Avenue Seal, Flowmeter Piston 18 Santa Ana, CA. 92707 Seal, Seat Seal

Bearing Engineering Ball Bearings 40 360 E. International General 'O' Rings

Airport Anchorage, Alaska 99518

Key Bellville, Inc. Bellville Washers 42,48 Box 191C

Leechburg, PA 15656

Lee Company Orifice/Orifice Systems 38

22 PPettipang Road 46

Westbrook, CT 06498 Orange Research, Inc Flowmeter Primary Magnet 22 140 Cascade Blvd. Flowmeter Piston 20 Milford, CT. 06460 Flowmeter Differential

Pressure Spring 21 Flowmeter Rotary Magnet 100 Indicating Needle 104 Gauge Housing 106

It will be understood that the invention is not limited to this specific embodiment herein above described, but may be used in other ways without departure from the scope of the invention as defined in the following claims.

Claims

1. A high or low pressure flow controller and metering device adapted for delivery and metering of gases and liquids substantially independent of upstream or downstream pressure fluctuations and capable of extremely low flow rates while contained in a single and complete housing having an inlet passageway through which flow enters in an orifice or system of orifices and thereby passing through establishes a differential pressure which is transmitted via specially placed pressure passages to an internal piston mounted magnet whose position is indicated via a rotary magnet and having flow continuing to a second orifice or system of orifices whereby differential pressure is controlled via a piston experiencing a force balance exerted by said differential pressure acting on referenced piston in conjunction with opposing springs, the force of either spring which can be externally adjusted to affect a change in differential pressure across, and hence, flowrate through the second orifice or system of orifices also affecting flow through the first orifice or system of orifices with the associated external meter indication changes.

2. A pressure/flow control device in accordance with Claim 1 which utilizes an internal piston in which an orifice or system of orifices is installed and the pressure differential across the piston is controlled by the pressure/flow control device to control or affect changes in flowrate through or pressure external to the pressure/flow control device.

3. A flow control device or pressure regulator whereby two or more orifices or orifice systems are engaged in series within the same flow path and whereby flow through either or any of the orifice or orifice systems is maintained or adjusted by differential pressure control or variance across one or more, but not all orifice or systems of orifices while utilizing the orifices or system of orifices for flowmetering and indication.

4. A regulator device utilizing opposing springs any or all of which may be externally loaded or unloaded to produce pressure changes within the device with the service of each and all springs being exclusive to pressure adjustment functions.

5. A regulator device utilizing a substantially frictionless spring consisting of one or more ball bearings and one or more Bellville washers, Bellville washer systems, coil springs or coil spring systems used in conjunction with the delivery of a spring system-induced force for purpose of pressure inducement or pressure adjustment within the regulator.

6. A regulator device utilizing a coating applied to a pin and seat configuration with the intent to seal microscopic surface defects and provide a complete and effective flow stoppage inclusive of, but not limited to, micro-flowrates.

7. A regulator or flow control device in accordance with Claim 1 wherein a portion thereof has been so designed as to provide inherent in device component structure a National Pipe Thread external to the device to effect ease of installation via a user supplied receiving National Pipe Thread and to provide an internal National Pipe Thread and quill configuration to support better fluid or gas delivery from the device to the affected process flow, each of the above in conjunction with an internal check valve, all inherent within the device structure and not external to the device structure.