US2501957A

US2501957A - Pneumatic control apparatus

Info

Publication number: US2501957A
Authority: US
Inventors: Coleman B Moore
Original assignee: Moore Products Co
Current assignee: Moore Products Co
Priority date: 1945-12-22
Filing date: 1945-12-22
Publication date: 1950-03-28
Anticipated expiration: 1967-03-28

Description

March 28, 1950 MOORE 2,501,957

1 PNEUMATIC CONTROL APPARATUS Filed Dec. 22. 1945 I I I I I I I I I I I l I I I J i U v v v 'J'IIIL'IIIIIIIIII A A A a INVENTOR.

ITTOk/VEY C'OLA-MA/V J 15/00/05 Patented Mar. 28, 1950 PNEUMATIC coN'rnoL ArrsnA'rUs Coleman B. Moore, Carroll Park, Pa., asslznor 'to Moore Products Co., Philadelphia, Pa., a on partnership Application December 22, 1945, Serial No.- 637,057

8 Claims. (Cl. 137-153) This invention relates to pneumatic control apparatus and more particularly relates to structure for controlling the bleeding or exhaust of fluid from such apparatus.

The invention further relates to an improved diaphragm construction for use in pneumatic control apparatus.

It has heretofore been proposed to employ a pneumatic circuit in which a plurality of diaphragm elements were separated and mounted to provide a chamber, the diaphragm's being mechanically connected at the central portions thereof for simultaneous movement and the chamber between the diaphragms being connected for exhaust or bleed to a lower pressure zone such as the atmosphere. In such a circuit,-

on one of the diaphragms, fluid at a variable pressure is effective, and, on the other diaphragm, fluid under pressure from a source is effective, the pressure on the latter diaphragm being controlled by a valve actuated by the movement of the diaphragms. With such a circuit, a valve is also customarily provided for controlling the delivery of fluid to the chamber between the diaphragms for exhaust. The diaphragms in the prior circuits, each being subjected to a relatively high differential of pressure, are necessarily of a strength and thickness to sustain the pressure applied thereon. This usually has the effect of materially reducing the flexibility of each of the diaphragms, as well as resulting in complications of structure."

In accordance with the present invention, a diaphragm construction is provided of a unitary character, which is quite flexible, which permits of the use of lighter diaphragm elements or membranes while maintaining adequate strength, which permits of free flow of the fluid to be dis-- charged, which will be inert to the fluids used, which will be free from any tendency to clog, and which will have numerous other advantageous features:

The nature and characteristic features of the invention will be more readily understood from the following description, taken in connection with the accompanying drawings formin part hereof. in which:

Figure 1 is a top or plan view of a relay provided with a diaphragm assembly in accordance with the present invention, parts being broken away to show the details of construction;

Fig. 2 is a vertical central sectional view taken approximately on the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary sectional view, enlarged, taken approximately on the line 3-3 of Fig. 1;

a 2 Fig. 4 is a horizontal proximately on the line 4-4 of Fig. 3;

Fig. 5 is a view similar to Fig. 3 showing a modi- I fled form of the invention and;

Fig. 6 is a horizontal section view taken approximately on the line 6-6 of Fig. 5.

It should, of course, be understood that the description and drawings herein are illustrative merely, and that various modifications and changes may be made in the structure disclosed without departing from the spirit of the invention.

Referring more particularly to the drawings, the diaphragm assembly Ill in accordance with the present invention and for purposes of illustration and explanation, is shown applied to a pneumatic relay although it will, of course, be understood that it is not restricted to use in the specific manner shown and that it has a variety of other applications in connection with other pneumatic control apparatus, such as-pressure regulators, pilot valves and the like.

The pneumatic relay shown for illustrative purposes, preferably includes an upper casing section H and a lower casing section l2 between which the diaphragm assembly 10, in accordance with the present invention, is interposed and held in position by studs l3. A chamber I4 is provided in the interior of the upper casing section II and above the diaphragm assembly ill, a pipe l5 being connected thereto for the application in the chambe ll of fluid at variable pressure.

The lower casing section l2 has a fluid inlet connection [6 for the supplying to the relay of fluid under pressure and a fluid delivery connection I'T. The fluid inlet connection I6 is preferably connected by a passageway [8 to a chamber [9 having a valve seat 2|] at the upper portion thereof and closed at its lower end by a plug 2|. Within the chamber is a valve seating member 22 is provided, mounted on andsecured to a valve stem '2 3, a spring 24 being interposed between the plug 2! and an abutment plate 25, secured to the stem 23 for urgingthe valve seating member 22 towards the valve seat 20.

A chamber 26 is also provided in the lower casing section l2 above the valve seat 20 andbelow the diaphragm assembly In and a passageway 21 is provided extending from the chamber 26 to the delivery connection l1.

The diaphragm assembly l0 preferably comprises a lower flat metallic ring 3| and an upper flat metallic ring 30. The

rings

30 and 3| may be of the same thickness although the lower ring 3| is preferably made thicker. and one of the rings sectional view taken apsuch as the ring II is provided preferably across its inner flat face with radially extending exhaust slots 32 at a plurality of locations. The outer ends of the slots 32 are preferably enlarged by the provision of circumferential slots 33 in both rings.

Above the upper ring 30, a diaphragm membrane member 34 is provided, which may be of any suitable sheet material such as rubber, synthetic rubber, such as neoprene, or any other soft highly flexible fluid tight material. A lower diaphragm member 35, which is preferably of the same type as the upper diaphragm member 34 is also provided. The

diaphragm members

34 and 35 may be made thinner or of lighter material than has heretofore been possible for particular pressures applied thereon for reasons which will presently appear. I

The

rings

30 and 3|, by reason of their thickness provide a space bounded on the upper side by the upper diaphragm member 34 and on the lower side by the lower diaphragm member 35. This space is in communication with the atmosphere or any other desired lower pressure zone through the exhaust slots 32. The

diaphragm members

34 and 35 are spaced and separated by an interposed support which is in e; gagement with the inner faces of each of the tion 39, in communication with the space between the

diaphragm members

34 and 35. In the modifled form of the invention illustrated in Figs. 5 and 6, one of the diaphragm members, such as the diaphragm member a, is provided, on the inner face thereof, with a plurality of spaced projections 45 which function as interposed supports by engagement at a plurality of locations over the inner face of the diaphragm member 34, spaces or passageways 45 thus being available between the projections 45.

The mode of operation will now be pointed out.

Fluid under pressure is supplied through the fluid inlet connection l6 and the fluid delivery connection I! is connected to the desired apparatus or instrument (not shown). Fluid at vari-v able pressure is effective through the pipe IS on the upper face of the diaphragm member 34. The pressure effective in the chamber l4 on the upper face of the diaphragm 34 is transferred in part by the fabric spacer layers 33 or by the projections 45 directly to the

lower diaphragm member

35 or 35a. The pressure effective in the chamber 26 is effective on the lower face of the diaphragm member 35 and is transferred in part by the spacer layers 35 or by the projections 45 to the upper diaphragm member 34.

diaphragm members

34 and 35 but need not be The resultant of the pressures in the chamber l4 and 26 efl'ects the desired positioning of the valve seat member 22 with respect to the valve seat 20 for controlling the delivery of pressure fluid past the valve seat 20 in accordance with the variable pressure in the chamber l4. The resultant pressure is effective for normally maintaining the port 40 closed by its engagement with the stem portion 39 of the stem 23. The

' pressure in the chamber i4 is thus effective for her 35, and transmitting or transferring the pressure effective on the lower face of the diaphragm member 35 through the support to the diaphragm 34, so that the pressure from either or both faces is effective simultaneously on the

diaphragm members

34 and 35. The support is also of a character which will permit of free passage of fluid between the

diaphragm members

34 and 35, is highly flexible, is adequately resistantto fatigue, is resistant to-crushing 'orother undesired deformatiomand is resistant to corrosion with the fluids employed. For this purpose one or more layers of open mesh supporting fabric 35 as illustrated in Figs. 1 to 5, inclusive,

is preferably provided. The fabric 36 may be of any desired material having the characteristics required and one suitable materialis screening made from the synthetic plastic known as Saran,

a copolymer of vinyl and vinylidene chloride. I

Support fabrics made from other synthetic plastic materials, such as nylon, and other materials,

such as glass fibres, catgut and the like could also be employed, so long as they have the required characteristics.

The

rings

30 and 3| are preferably cemented or otherwise secured in. assembled relationship,

and the

diaphragm members

34 and 35 are prefto be guided and seated. The valve seating member 35 has a port 40, controlled by. the stem porpositioning the valve seat member 22 and permitting' fluid to flow past the valve seat 20 and to the chamber 25 for delivery through the passageway 21 and the delivery connection ii.

If the variable pressure in the chamber 14 should decrease thereby tending to produce an effect where an excessive quantity of fluid or excessive pressure is available inithe chamber 26, the pressure effective in the chamber 26 tends to raise the diaphragm-

members

35 and 34. This permits the valve seat member 22 to move closer to the valve seat 20, and if the unbalance due to the excess pressure or quantity of fluid is not relieved-further movement tends to open the port 4!! controlled by the stem portion 29. Fluid is thereby permitted to pass through the port 40 and into the space between the

diaphragm members

35 and 34 and pass outwardly for discharge through the

slots

32 and 33. As soon as the excess has been discharged, or upon an increase in the variable pressure effective in the chamber I 4, the port 40 will again be positioned with respect 'to the stem portion 39 thereby reducing or cutspace between said membranes.

phragm device comprising a flat ring member having a discharge passageway therein, flexible diaphragm membranes of thin fluid tight material on each side of said ring member and in engagement with the faces thereof, and membranes spacing and supporting means for permitting fluid flow disposed between said diaphragm membranes and comprising a pervious disc in supporting engagement with said membranes over the facing areas thereof within the ring member, and means for controlling the access of fluid to the space between said membranes.

4. In pneumatic control apparatus, a diaphragm device comprising a pervious central flexible disc portion bounded on opposed sides by fluid tight portions, and means for controlling the access of fluid to the central portion for discharge.

5. In pneumatic control apparatus, a diaphragm device comprising closely spaced flexible diaphragm members, means for spacing said diaphragm members at their outer edges, said means including a discharge passageway, and a sheet portion of flexible open mesh fabric supporting said diaphragm members at a plurality of locations over their facing areas and for permitting the flow of fluid to said passageway, and means for controlling the access of fluid to the space between said diaphragm members for discharge.

6. In pneumatic control apparatus, a diaphragm device comprising a pair of flexible diaphragm members, closely spaced and separated at their outer edges and having a discharge opening from the space therebetween, and a disc of pervious material for supporting said diaphragm members at a plurality of closely spaced locations over their facing areas and permitting the flow of fluid to said discharge opening, and

means for controlling the access of fluid to the space between said diaphragm members for discharge.

7. In pneumatic control apparatus, 9. diaphragm device comprising closely spaced flexible diaphragm members, a ring member for spacing said diaphragm members at their outer edges, said ring member having a discharge opening, and at least one layer of flexible screening interposed between said diaphragm members for spacing said diaphragm members and permitting the flow offluid to said discharge opening, and means for controlling the access of fluid to the space between said diaphragm members for discharge through said opening.

8. In pneumatic control apparatus, a diaphragm device comprising closely spaced flexible diaphragm members, a ring member for spacing said diaphragm members at their outer edges, said ring member having a discharge opening and supporting projections on one of said diaphragm members for spacing said diaphragm members and permitting the flow of fluid to said discharge opening and means for controlling the access of fluid to the space between said diaphragm members for discharge through said opening.

COLEMAN B. MOORE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS