Low pressure fitting

• US 4,690,437 A
• Filed: 02/27/1986
• Issued: 09/01/1987
• Est. Priority Date: 02/27/1986
• Status: Expired due to Term

• Current Assignee: Alltech Associates Incorporated (WR Grace & Company)
• Original Assignee: Alltech Associates Incorporated (WR Grace & Company)
• Inventors: Anderson, James M. Jr.
• Primary Examiner(s): Husar, Cornelius J.
• Assistant Examiner(s): Nicholson, Eric K.
• Application Number:
  US06/834,003
• Time in Patent Office: 551 Days
• Field of Search: 285/356, 285/911, 285/353, 285/339, 285/343, 55/3896, 210/656, 210/198.2
• US Class Current: 285/356
• CPC Class Codes: G01N 30/6004 end pieces
• CPC Class Codes: G01N 30/6026 Fluid seals
• CPC Class Codes: G01N 30/6034 joining multiple columns
• CPC Class Codes: Y10S 285/911 Glass

Abstract

The disclosed fitting connects a tubing end to a fluid conducting member which have a fluid port and end walls surrounding the port and a threaded portion surrounding the end wall. The fitting comprises a ferrule of resilient deformable material having a forward portion with a wide flat sealing surface which is adapted to mate with and sealingly engage the end wall surrounding the port. The ferrule has a throughbore with a diameter through its rearward portion being sufficient to receive the tubing end and the diameter through the forward portion being smaller than the tubing exterior thereby forming a tubing abutting shoulder within the ferrule. The ferrule is forced into sealing abuttment with the end wall of the fluid conducting member and into sealing engagement around the tubing by means of a fastener having a throughbore for receiving the tubing which is flared at its forward end to present conical walls for axially engaging the rearward end of the ferrule. The fastener has a threaded portion for threadedly engaging the threaded portion of the fluid conducting member, thus when the fastener is tightened on the threaded portion of the fluid conducting members, the conical walls of the forward end of the fastener will engage and force the rearward portion of the ferrule inwardly into sealing engagement around the tubing within the ferrule.

Claims

1. A fitting for connecting in pressure-tight fluid sealing relationship a tubing end to a fluid conducting member having a pressurizable fluid port terminating in a counterbore having an end wall surrounding said port, a cylindrical side wall and a threaded portion extending outwardly from said side wall;

said fitting comprising a ferrule of resisilent deformable material having a forward portion, the outer diameter of which is substantially greater than the outer diameter of the tubing and substantially less than the diameter of the fluid conducting member counterbore and which has an end surface on said forward portion configured to mate with and sealingly engage the end wall surrounding the port, and a rearward portion which is rearwardly tapered, said ferrule having a throughbore with its diameter at least through said rearward portion being sufficient to receive and surround the tubing end;

a fastener having a threaded portion for threadedly engaging the threaded portion of said fluid conducting member counterbore and having a throughbore for receiving the tubing, the throughbore being outwardly tapered at the forward end of said fastener to present conical walls for axially engaging said ferrule rearward portion, the taper angle of the conical throughbore walls at the forward end of said fastener being substantially greater than the taper angle of the rearward portion of said ferrule;

whereby when the threaded portion of said fastener is tightened on the threaded portion of the fluid conducting member, the conical forward walls of said fastener will engage and force the tapered rearward portion of the ferrule laterally inwardly into sealing engagement around the surrounded tubing end only at approximately the point the tubing enters the ferrule rearward portion and the forward portion of the ferrule will be forced axially forwardly into sealing engagement with the counterbore end wall surrounding the port of said fluid conducting member and in such a sealing engagement said ferrule will be out of contact with the side wall of the counterbore.

2. The structure of claim 1 wherein said ferrule throughbore in said forward portion is smaller than the tubing exterior, thereby preventing said tubing from passing through said throughbore in the forward portion of said ferrule.

3. The structure of claim 2 wherein the taper angle of the conical throughbore walls at the forward end of the fastener is at least approximately double the taper angle of the rearward portion of the ferrule.

4. The structure of claim 2 wherein the change of diameter of said ferrule throughbore is abrupt forming a tube-abutting shoulder at the juncture of said forward and rearward ferrule portions.

5. The structure of claim 1 wherein the end surface of said ferrule forward portion is annular and disposed in a plane substantially perpendicular to the axis of said ferrule throughbore.

6. The structure of claim 5 wherein said ferrule forward portion annular end surface has a sealing area surrounding said throughbore of at least five times the cross sectional area of the largest portion of the throughbore.