US1147872A - Balanced slide-valve. - Google Patents

Description

M. A. KNAPP BALANCED SLIDE VALVE.

APPLICATION FILED SEPT.29. 1914.

1,147,872. Patented July 27', 1915, 2 sums-sum 1.

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BALANCED. SLIDE VALVE.

APPLICATION FILED SEPT-29. 19M.

1,147,872. I Patented July 27, 1915.

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MERRITT A. KNAPPQ OF ROSALIA, WASHINGTON.

, BALANCED SLIDE-VALVE.

. To all whom it may concern Be it known that I, Mnnnrrr A. KNAPP, a citizen of the United States, residing at Rosalia, in the county of Whitman and State of 1V ashington, have invented certain new and useful Improvements in Balanced SlideValves, of which the following is a specification. v

This invention relates to that class of balanced valves in which pressure within the steam chest is utilized for thrust of the slide valve upon its seat and against a balancing piston to relieve pressure of the valve upon its seat, the relative areas of the valve and piston being such as to provide suflicient preponderance of pressure on the valve to hold the same lightly in working engagement on its seat. Heretofore in constructions of this character, reliance has been placed upon exhaust steam on the opposite end of the piston to overcome any tendency of the piston to unduly rise and unseat the valve.

The novel feature of this invention consists in providing means for exerting ace-nstant thrust on the balancing piston to seat the valve, such means being adjustable so as to permit of the exertion of any desired degree of seating pressure.

Other features and objects of'the inven tion will be more fully described in connec tion with the accompanying drawings, and will be more particularly pointed out in and by the appended claims.

In the drawings: Figure 1 is a vertical sectional view ofan engine cylinder provided with my improved balance valve structure. Fig. 2 is a sectional view on line 22 of Fig. 1. Fig. 3 is a perspective view of the slide valve and balancing piston, detached from the structure.

Like characters of reference designate similar parts throughout the different figures of the drawings.

As illustrated, 1 designates an engine cylinder in which an engine piston 2, is reciprocable. A piston rod 3 extends through a packing gland 4:, in the usual manner and a portion of the frame is indicated at 5. The engine cylinder 1 is provided with a steam chest 6, and a valve seat 7, ports 8 being shown as leading from the steam chest to the cylinder. A slide valve is shown at 9, and is of the hollow type so as to establish communication between one of the ports 8 and the exhaust cavity 10. An exhaust pipe 11 Specification of Letters Patent.

. Patented July 27, 1915.

Application filed September 29, 1914. SerialNo. 864,078.

leads from the exhaust cavity 10. The slide valve 9 is provided with an attaching lug 12, which is bored, as at 13, to receive a valve rod 14:, the latter being shown as extending through a packing gland 15. The inserted end of the rod 14 is secured in the bore 13 of the lug 12 bymeans of nuts 16. Projecting upwardly from the lug 12 are ears 17 between which is pivoted a connecting rod 18, as indicated at 19. The upper end of the connecting rod 18 is pivoted at 20 to a balancing piston 21. y

The steam chest .6 is provided with a removable cover 22, which is cast integral with a balancing cylinder 23 and the latter, is in free and constant communication with the steam chest 6, at one end Of s-aid cylinder. The parts are so proportioned that the chest steam thrust face 23, of-the piston 21, will be slightly reduced in. area with respect to the upper face or area of the slide valve 9 so that there will be a slight preponderance of steam thrust pressure on the valve 9, over that against piston 21 sothat during operation the valve 9 will be held seated with a slight working pressure.

The upper end of cylinder 23 is provided with a removable head 24, and a bearing bracket 25 is removably secured to said head by certain of the bolts 26 which anchor the head 24 to the cylinder 23. The bearing bracket 25 is provided with a bearing hub 27. Slidable in said hub 27, and through a packing gland 28, is a plunger rod 29, which extends into the cylinder 23 for engagement against the upper or exhaust thrust face 30, of the piston 21. A nut 31 is threaded on the plunger rod 29 and a washer 32 is disposed on said nut. Interposed between the washer 32 and the bearing hub 27 is an expansively acting spring 33 which functions to force the lower end of the rod 29 into constant pressure engagement against the exhaust thrust face 30 of the piston 21. By reason of the fact that the valve 9 reciprocates, a slight up and down movement will be imparted to piston 21, however, throughout the movement of piston 21 the pressure plunger 29 will exert a practically uniform pressure thereagainst in opposition to the steam chest thrust against the face 23, of the piston 21. This yielding and constant pressure is in one embodiment of the invention, a supplemental means for adding to the downward pressure on piston 21 exerted by exhaust steam. However, in the event that the designed preponderance of pressure on the slide valve 9 is not sufi icient, and further, if under back pressure it Was necessary for the valve 9 to lift, the spring 33 would accommodate for either of such actions or exigencies and thereafter automatically and quickly restore the parts to their normal Working position. Byreason of the nut 31, the supplemental thrust of the plunger rod 29 may be varied in such a manner that the very nicest and most accurate balance of the parts may be obtained under Widely varying steam pressure.

A connection 34- delivers exhaust pressure from pipe 11 to an elongated port 35, which opens into the cylinder 23 above the piston 21, although in some embodiments, this exhaust pressure may be omitted, and reliance placed Wholly upon the adjustable pressure means.

It is believed that the utility and advan- H tages of my invention Will be fully understood from the foregoing description, and

While I have herein shown and described one specific form of my invention, I do not Wish to be limited thereto except for such limitations as the claims may import.

I claim 1. In an improved balanced slide valve structure,a steam chest having a slide valve seat and a balancing cylinder With one end of the latter in constant free communication with said chest, a slide valve reciprocable on said seat, a balancing piston slidable in said cylinder and pivotally connected With said slide valve and under thrust of steam in said chest on one face of said piston to relieve pressure of said valve on its seat, a connection delivering exhaust steam from said chest to said cylinder for thrust on the remaining face of said piston to partially counter-act chest steam pressure, and adjustable spring actuated means in constant pressure engagement with said piston during movement of the latter for supplementing the thrust of exhaust steam on the exhaust face of said piston, substantially as de scribed.

2. In an improved balanced slide valve structure, a steam chest having a slide valve seat and 'a balancing cylinder With one end of the latter in constant free communicationWith said chest, a slide valve reciprocable on said seat, a balancing piston slidable in said cylinder and pivotally connected With said. slide valve and under constant thrust of steam in said chest on one face of said piston to relieve pressure of said valve on its seat, a connection delivering exhaust from said chest to said cylinder for thrust on the remaining face of said piston to partially counter-act chest steam pressure, a plunger rod slidable in said cylinder against the exhaust face of said piston, and a spring means adjustably connected With said plunger and abutting said cylinder for holding said plunger in constant pressure engagement against said piston to supplement the thrust of exhaust steam on the exhaust face of said piston, substantially as described.

3. In an improved balanced slide valve structure, a steam chest having a slide valve seat and balancing cylinder With one end of the latter inconstant free communication With said chest, a slide valve reciprocable on said seat, a balancing piston slidable in said cylinder, a piston rod having one endpivoted to said piston and its other end pivoted to said slide valve, one face of said piston being under constant thrust from said steam chest and a connection delivering exhaust steam to said cylinder for thrust on the remaining face of said piston to partially counter-act the thrust of the chest steam, a plunger rod slidable in said cylinder against the exhaust face of said piston, an adjustable nut on said plunger, and a spring interposed between said nut and said cylinder for maintaining said rod in constant thrust engagement with said piston to supplement the thrust of said exhaust steam, substantially as described.

In testimony whereof I affix my signature in presence of two Witnesses.

MERRITT A. KNAPP.

V'Vitnesses r F. C. REED, J. W. BArLoRs.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents Washington, .D. C

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