Fluid apparatus and methods, as for inflating inflatable structures

• US 4,566,862 A
• Filed: 07/19/1984
• Issued: 01/28/1986
• Est. Priority Date: 02/23/1982
• Status: Expired due to Fees

• Current Assignee: General Pneumatics Corp.
• Original Assignee: General Pneumatics Corp.
• Inventors: Halavais, Richard A.
• Primary Examiner(s): Look, Edward K.
• Application Number:
  US06/632,267
• Time in Patent Office: 558 Days
• Field of Search: 417/187-189, 417/190, 417/191, 417/196, 417/198, 417/174, 417/151, 417/178, 441/40, 441/41, 137/895
• US Class Current: 417/189
• CPC Class Codes: B63C 2009/0076 Inflation devices making use of the Venturi-effect for enhancing the gas flow from the pressurized gas source by entraining ambient air, e.g. using eductor-jet pumps for decreasing inflation time
• CPC Class Codes: F04F 5/16 displacing elastic fluids
• CPC Class Codes: F04F 5/48 Control

Abstract

In a system for inflating airslides and the like, the pressure of the primary gas supplied to an ejector is controlled so as to maintain a constant mass flow rate into the airslide over its inflation cycle. A controller for controlling the primary gas pressure may be integrated into the ejector. A novel ejector employs flow shaping of an expanding primary gas stream within a draft tube to create a flow potential that produces entrainment of a secondary fluid. The draft tube may comprise telescoping sections to provide an ejector having a compact structure but which is capable of affording a substantial mixing length for the primary gas and secondary fluid when operated. The draft tube may be biased into engagement with flapper valves that close the secondary fluid openings in the ejector to afford positive closure of the openings. An argon and carbon dioxide primary gas mixture enables entrainment of a given quantity of secondary fluid within a smaller quantity of primary gas.

Claims

1. Apparatus for controlling the pressure of a primary gas supplied to a mass flow augmentation device of the type that employs the flow of the primary gas through a containment structure for entraining a secondary fluid to produce a combined fluid flow through the containment structure, comprising a housing having a portion adapted to be received within a base member of the mass flow augmentation device, pressure sensitive means disposed within the housing, means for applying a static pressure to the pressure sensitive means, and means responsive to the pressure sensitive means for supplying an output signal adapted for controlling the primary gas pressure dependent upon the static pressure, said housing comprising a cup-shaped member having an elongated tubular portion extending therefrom, the tubular portion being adapted to be received within an opening in the base member with an adjacent surface of the cup-shaped member in engagement with a surface of the base member, the static pressure applying means comprising a groove in said surface of the cup-shaped member adapted to be aligned with a hole in the surface of the base member that is in communication with a static pressure sensor, the cup-shaped member having another hole therein to provide a passageway between the groove and a chamber within the housing.

2. The apparatus of claim 1, wherein the pressure sensitive means comprises a diaphragm within the chamber and movable valve means disposed within a bore of said tubular portion and connected to the diaphragm, and wherein said tubular portion has a first opening therethrough in communication with said valve means for receiving a portion of the primary gas pressure supplied to said mass flow augmentation device, a second opening therethrough in communication with the valve means for providing the output signal, the output signal being primary gas pressure, and a third opening therethrough for providing a vent, the valve means being adapted to alternately provide a fluid passageway between the first opening and the second opening and between the second opening and the third opening.

3. The apparatus of claim 2, wherein the valve means comprises a close-fitting spindle within the bore of the tubular portion, the spindle having an axial bore extending partially therethrough, having first, second and third circumferential grooves in its periphery, and having a radial hole located in each groove in communication with the axial bore, said grooves being positioned in the spindle with respect to said openings in the tubular portion such that in a first position of the spindle a fluid passageway is provided between the first and second openings and the third opening is sealed, and such that in a second position of the spindle a fluid passageway is provided between the second and third openings and the first opening is sealed.

4. The apparatus of claim 2 further comprising means for applying the dynamic pressure of the combined fluid flow to said diaphragm such that said diaphragm moves in response to the difference between the static pressure and the dynamic pressure, said dynamic pressure applying means comprising another groove in said surface of the cup-shaped member adapted to be aligned with another hole in the surface of the base member that is in communication with a dynamic pressure sensor, the cup-shaped member having another hole therethrough positioned in said other groove to communicate the dynamic pressure to the diaphragm.

5. The apparatus of claim 4, wherein said first-mentioned groove and said other groove comprise concentric annular grooves in the surface of the cup-shaped member, and wherein the surface of the cup-shaped member and the surface of the base member are cooperative to provide a fluid seal between said grooves.

6. Apparatus of the mass flow augmentation type comprising a housing having an inlet for primary gas and having an opening therein for secondary fluid, draft tube means associated with the housing, and means for producing a primary gas flow through the draft tube means so as to cause entrainment of secondary fluid, the draft tube means comprising movable telescoping draft tube sections normally biased together to a non-extended position at which the draft tube sections are in overlapping relationship and located substantially within the housing, and means responsive to the introduction of primary gas into the housing for moving the draft tube sections to an extended position at which the draft tube sections form a draft tube having a length that optimizes the energy transfer between the primary gas and the entrained secondary fluid.

7. The apparatus of claim 6, wherein said draft tube sections are sized such that in the extended position they provide a draft tube having a length-to-diameter ratio greater than 2:

1.

8. The apparatus of claim 7, wherein the draft tube sections are sized to provide a length-to-diameter ratio of the order of 6 to 8:

1.