Shull Perforating Co. v. Cavins

Ninth Circuit

Shull Perforating Co. v. Cavins

94 F.2d 357, 36 U.S.P.Q. (BNA) 217, 1938 U.S. App. LEXIS 4419

CourtCourt of Appeals for the Ninth Circuit

DecidedJanuary 10, 1938

DocketNo. 8291

StatusPublished

Cited by15 cases

This text of 94 F.2d 357 (Shull Perforating Co. v. Cavins) is published on Counsel Stack Legal Research, covering Court of Appeals for the Ninth Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook

Shull Perforating Co. v. Cavins, 94 F.2d 357, 36 U.S.P.Q. (BNA) 217, 1938 U.S. App. LEXIS 4419 (9th Cir. 1938).

Pincite

Opinion

WILBUR, Circuit Judge.

This is an appeal from an interlocutory-decree in a suit brought by appellees charging infringement of patent ‘No. 1,917,211 issued to O. A. Cavins. The master found that claims 18 and 24 of the patent were valid and were infringed. The court sustained the finding, and entered an interlocutory decree for an injunction and an accounting.

Appellant contends that the patent is invalid because anticipated by previous patents, and that if valid the claims are limited to a narrow field by the prior art, by the nature of the invention, and by the specifications, and that thus construed there is no infringement.

The patent relates to a bailer for use in deep wells, particularly oil wells, for the purpose of removing sand and other debris from the bottom of the well. The bailer is of the type called a suction bailer or differential pressure bailer; the name being derived from the fact that the bailer is composed of two cylinders, one superimposed upon the other, separated by partition with a valve therein. On the bottom of the lower cylinder is a flap valve which is open while the bailer is descending so that the lower cylinder or chamber is filled with fluid under the hydrostatic pressure of the contents of the well. The upper cylinder is airtight and retains its content of air at atmospheric pressure until the bottom of the well is reached. The two cylinders are separated by a partition containing a valve which opens automatically shortly after the bottom of the well is reached. Upon the opening of the valve the hydrostatic pressure, which in deep wells may be several thousand pounds per square inch, forces the contents of the lower chamber into the upper chamber, and sucks sand and débris from the bottom of the well into the lower chamber, which is called the sand-chamber, where it is retained by the flap valve while the apparatus is hoisted to the surface. We place in the margin claims 18 and 24 of the patent.¹ These claims are summarized by the appellees as follows:

“(1) A sand chamber having a bottom inlet.

“(2) A closed, substantially air-tight air-chamber.

“(3) A third member that is vertically movable with relation to the other two members; that is mounted between the chambers ; and that is called a ‘valve.’

“(4) Means for effecting a delayed movement of the valve towards its open position when the bailer lands on an obstruction or at the sand in the well.”

It is claimed by the appellant that this patent was anticipated by two early patents; one issued January 21, 1868, to John F. Carll, No. 73,577, and one issued to William H. Birge on August 7, 1877, No. 193,-915. A description of these earlier devices will not only help to understand the state of the art, but also to understand the more complicated device described in the Cavins patent. Before doing so, however, it should be stated that the principal emphasis of the Cavins patent is upon the delayed action of the valve separating the sand-chamber and the air-chamber. Some form of delayed action is essential to avoid the opening of the valve by hydrostatic pressure, while the bailer is descending, or by striking obstructions projecting from the side of the well or the shoulder at the junction between larger and smaller casings. It is apparent that these difficulties increase with the depth of the well.

[360]*360Returning to the device of Carll, we show the patent drawing:

This Carll sand pump might be considered as a single cylinder, instead of two cylinders as in the Cavins patent, with a piston similar to that used in a steam engine closing the upper end, or air-chamber, from the lower end, or sand-chamber. The piston is held in place until the bottom is reached when the contact of the piston rod with the bottom releases the piston which is at once forced toward the top of the upper chamber by hydrostatic pressure, thus increasing the size of the lower chamber and filling the bottom of it with debris from the bottom of the well. The piston, before its operation, is seated on a shoulder and for that reason partakes of some of the characteristics of a valve. The appellant contends that it is- a valve. , We will turn later to a description of the means by which the piston is released in connection with the appellant’s claim that we find in this patent a delayed action in the opening of the valve, which anticipates the claim of patent in suit for a delayed action of the valve. It is clear, however, that the action of the piston in the Carll patent is delayed until the end of' the piston rod strikes the bottom of the well, and, as will presently appear, for a short time thereafter.

The Birge device, patent 193,915, is shown in the accompanying drawings:

[361]*361It has two chambers separated by a valve so arranged that on striking the bottom the upper section telescopes into the lower until it reaches a stopper collar which prevents further telescoping. The opening in the partition between the two chambers is relatively small and closed by a valve with a mushroom-shaped head. The stem of this valve extends downward into and is securely attached to the lower cylinder while the upper end of the stem passes through the head of the upper cylinder. The hydrostatic pressure on the valve is balanced because the end surface of the valve and of the valve stem as well as the upper end of the valve stem projecting through the upper chamber-head, is subjected to the hydrostatic pressure of the well.

, In the Birge device, the valve begins to leave its seat the moment any telescoping action occurs. In view of the fact that the valve is a balanced valve, it is held in place during descent solely by the weight of the lower chamber which is suspended from the valve stem. In this device the loading occurs automatically when the bottom of the* sand pump lands on the bottom of the well, except in case of mishap where telescoping occurs by reason of striking some obstruction before the bottom is reached.

With reference to securing delayed action of the valve in the Birge patent to give an opportunity for the lower edge of the bailer to dig into the debris when it reaches the bottom of the well before the valve opens, appellant suggests that such delay could be secured by the simple mechanical device of converting the mushroom shaped valve head into a piston and by forming a cylinder around the piston. Then the opening of the valve would be delayed until the piston or valve left the cylinder and the length of the cylinder would measure the delay. 0

Appellant claims that such a change involves no inventive genius, merely mechanical skill, and that therefore, the Birge device completely anticipates the Cavins patent, including the delayed action of the valves in appellees’ patent. If this 'claim is not sustained he points to the earlier patent of Carll to show that the piston therein is prevented from leaving its seat, until the end of the piston stem has been completely stopped in its descent by the material in the bottom of the well, and also for the short time thereafter required for the operation of the mechanism which releases the piston and thus permits the hydrostatic pressure to force it upward. A brief description of this releasing device is necessary for an understanding of appellant’s claim of anticipation over the appellees’ patent. We have thus far spoken of the stem of the piston as though it were a solid rod extending through the flap valve at the bottom of the bailer and beyond.

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