GB2354056A

GB2354056A - Float operated pumping device

Info

Publication number: GB2354056A
Application number: GB9921132A
Authority: GB
Inventors: Andrew Philip Dawson
Original assignee: Spirax Sarco Ltd
Current assignee: Spirax Sarco Ltd
Priority date: 1999-09-07
Filing date: 1999-09-07
Publication date: 2001-03-14
Anticipated expiration: 2019-09-07
Also published as: GB2354056B; JP2001132894A; GB9921132D0; JP4656707B2

Abstract

A float operated device such as a pressure powered pump has a chamber 8 in which a float 10 is supported by a lever 12 for pivotable movement. The float 10 operates a toggle mechanism 28 by way of an arm 18 and extension 20 rigidly connected to the lever. Lever 12 also connected by a pivotably operating rod 48 to a valve element 44 controlling flow through a condensate outlet 38. The toggle mechanism 28 and the float 10 are supported by a cover 6, which is also provided with motive fluid inlet and outlet ports 32, 34, a condensate inlet 36 and the condensate outlet 38. The chamber 8 is defined by the cover 6 and a bowl portion 4 which is removable to allow servicing of the moving parts. The toggle mechanism operates to open/close the motive fluid inlet port 32. The motive fluid is preferably steam.

Description

2354056 FLOAT OPERATED DEVICES This invention relates to a float operated

device such as a pressure powered pump.

Pressure powered pumps are used in steam systems in order to raise condensate to a condensate return system from which the condensate is reintroduced to the steam generating boiler. Such pumps comprise a chamber in which the condensate accumulates, to be periodically discharged by the periodic admission of steam and venting of the chamber under the control of a float which is responsive to the level of condensate in the chamber.

one such pump is disclosed in British patent specification 2329451A. That pump comprises a flattened float, or a float comprising two elements disposed side-by-side, which is supported in the chamber by a parallelogram linkage. The chamber comprises a bowl portion and a cover. Inlet and outlet connections for the condensate are provided on the bowl portion, while connections for the steam are provided on the cover, which also supports the parallelogram linkage and a toggle mechanism for controlling the admission and venting of steam. This causes inconvenience when inspecting or sez7vicing the device, since access to the chamber.cannot be achieved without disconnecting either the steam connections or the condensate connections.

Also, while the special float construction and the parallelogram linkage can be justified economically in a unit capable of dealing with relatively large condensate flows, this is not so for smaller units.

According to the present invention there is provided a float operated pumping device comprising a float supported by a lever for pivotable movement upwardly and downwardly within a chamber in response to the level of liquid in the chamber, the chamber having an inlet and an outlet for pumped fluid and inlet and outlet ports for a motive fluid, the float. being connected to a toggle mechanism which is operable by movement of the float to actuate control means for controlling flow of the motive fluid into and/or out of the chamber, and the lever being operatively connected to a valve controlling the flow of the pumped fluid through the outlet.

A device in accordance with the present invention can be manufactured relatively economically while retaining a compact configuration.

The lever is preferably rigidly connected to the float. This may be achieved by mounting the float on an arm to which the lever is rigidly attached.

The arm may be connected to one end of a spring of the toggle mechanism.

The lever is preferably pivotably connected to an operating rod of the valve.

In a preferred embodiment, the chamber is formed within a housing comprising a bowl portion and a cover, the lever and the toggle mechanism being supported on the cover and the motive fluid inlet and outlet ports and the pumped fluid inlet and outlet being formed in the cover.

Another aspect of the present invention provides a float operated pumping device comprising a float supported by a lever for pivotable movement upwardly and downwardly within a chamber in response to the level of liquid in the chamber, the chamber being formed within a housing comprising a bowl portion and a cover, which cover supports the lever and has an inlet and an outlet for pumped fluid and inlet and outlet ports for a motive fluid, the float being connected to a toggle mechanism which is supported by the cover and is operable by movement of the float to actuate control means for controlling flow of the motive fluid into and/or out of the chamber.

with such a construction, the bowl portion may be removed from the-cover without disturbing any of the fluid connections, to gain access in a simple manner to the chamber. Also, the entire pump mechanism, comprising the float, the toggle mechanism, the control means and all associated components, may be supported on the cover.

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

Figure 1 is a cross-sectional view of a pressure powered pump; and Figure 2 is a view of the pump taken in the direction of the arrow II in Figure 1.

The pump comprises a housing 2 assembled from a bowl portion 4 and a cover 6. A chamber 8 is formed within the housing 2. A float 10 is,situated within the chamber 8 and is supported by a lever 12 which is connected at a pivot location 14 to a support 16 secured to the cover 6.

The lever 12 is formed integrally with an arm 18 having an oblique extension 20. The float 10 is rigidly secured to the arm 18 by a bolt 22. The extension 20 is pivotably connected to a spring support 24 at one end of a spring 26. The spring 26 is part of a toggle mechanism 28 which operates in the same manner as the toggle mechanism of the pumps disclosed in British Patent Specification 2329451A, and so will not be discussed in detail in the present specification.

The toggle mechanism is mounted on the cover 6 by means of bolts 30 and serves to actuate valves which cooperate with an inlet port 32 and an outlet port 34 formed in the cover 6.

The cover 6 is also provided with an inlet 36 and an outlet 38 for condensate. The inlet 36 is provided with a FLAP valve 40.

The outlet 38 is situated in the lower region of the chamber 8 and flow through it is controlled by a valve assembly 42. The assembly 42 comprises a valve seat 44 which has a central bore 45 and a transverse bore 47. A non-return element 46 is provided in the valve seat 44 to prevent flow through the bore 45 in the direction towards the chamber 8. An operating rod 48 has a head 49 which is accommodated in the central bore 45 of the valve seat 44 for movement along the bore 45 into and out of sealing contact with a shoulder 51 formed within the valve seat 44. The end of the operating rod 48 away from the head 49 is pivotably connected to the lever 12 at a position close to the junction between the lever 12 and the arm 18.

For operation, the pump shown i.n the drawings is fitted in the condensate return of a process steam system, with the inlet 36 connected to the drain side of the condensate return, and the outlet 38 connected to the boiler return. Furthermore, the inlet port 32 is connected to a steam line, and the outlet port 34 is connected to a steam exhaust.

In operation, in the position shown in Figure 1 the float 10 is in its lowermost position and consequently the operating rod 48 is lowered so that the head 49 of the operating rod 48 engages the shoulder 51 of the valve seat 44 to close the outlet 38. Consequently, condensate entering through the inlet 36 will accumulate in the chamber 8.

In the position shown in Figure 1, the toggle mechanism 28 is positioned so as to close.the steam inlet port 32 and leave the steam outlet port 34 open.

As condensate accumulates in the chamber 8, the float rises and this movement will cause operating rod 48 to move upwardly, so lifting the head 49 off the shoulder 51 to allow flow through the transverse bore 47 and the central bore 45 to the outlet 38.

Condensate can then flow from the chamber 8 to the boiler of the steam system. If flow through the outlet 38 is faster than the incoming flow through the inlet 36, the float will fall again, and the operating rod 48 will move down to return the head 49 into sealing contact with the shoulder 51, so closing the outlet 38.

If, however, the rate of flow through the inlet 36 exceeds that through the outlet 38, the float will continue to rise and, as it approaches the upper limit of its travel, the toggle mechanism 28 will switch so as to close the steam outlet port 34 and to open the steam inlet port 32. Steam under pressure then enters the chamber 8 forcing the condensate-,through the outlet 38. At the same time, the increased pressure within the chamber 8 closes the flap valve 40 to prevent loss of pressure through the inlet 36.

As the level in the chamber 8 drops, so does the float 10 and, as it approaches its lowermost position, the toggle mechanism switches again to return the valves at the steam inlet port 32 and the steam outlet port 34 to their previous positions, so venting the chamber S. Similarly, theconsequential movement of the lever 12 will lower the operating rod 48 to cause the head 49 to close the outlet 38 again. The non return element 46 opens to permit this closing movement without resistance from back pressure in the line connected to the outlet 38.

If it is necessary to inspect the mechanism within the housing 2, or to service the internal components, the bowl portion 4 can be removed from the cover 6 after undoing connecting bolts 50. This can be achieved without disturbing any of the connections to the inlet 36, the outlet 38, the steam inlet port 32 or the steam outlet port 34. Thus, the cover 6 can remain in position in the condensate return after closing isolating valves in the associated condensate and steam lines.

By supporting the float 12 by means of a single lever 12 which also serves to move the operating rod 48 to control flow through the outlet 38, significant economies in manufacture can be achieved. Although the tension in the spring 26 needs to be adapted to the weight and buoyancy of the float 10, the operation of the toggle mechanism 28 by way of the arm 18 and the extension 20 provides reliable operation of the valves controlling the-steam ports 32 and 34.

Claims

1. A float operated pumping device comprising a float supported by a lever for pivotable movement upwardly and downwardly within a chamber in response to the level of liquid in the chamber, the chamber having an inlet and an outlet for pumped fluid and inlet and outlet ports for a motive fluid, the lever being rigidly connected to an input element of a toggle mechanism which is operable by movement of the float to actuate control means for controlling flow of the motive fluid into and/or out of the chamber, and the lever being operatively connected to a valve controlling the flow of the pumped fluid through the outlet.

2. A device as claimed in claim 1, in which the lever is rigidly connected to the float.

3. A device as claimed in claim 2, in which the float is mounted on an arm to which the lever is rigidly attached.

4. A device as claimed in claim 3, in which the arm is connected to the input element of the toggle mechanism.

5. A device as claimed in claim 4-, in which the input element of the toggle mechanism comprises a spring support of a spring of the toggle mechanism.

6. A device as claimed in any one of the preceding claims, in which the lever is pivotably connected to an operating rod of the valve.

7. A device as claimed in any one of the preceding claims, in which the chamber is formed within a housing comprising a bowl portion and a cover, the lever and the toggle mechanism being supported on the cover and the motive fluid inlet and outlet ports and the pumped fluid inlet and outlet being formed in the cover.

B. A float operated pumping device comprising a float supported by a lever for pivotable movement upwardly and downwardly within a chamber in response to the level of liquid in the chamber, the chamber being formed within a housing comprising a bowl portion and a cover, which cover supports the lever and has an inlet and an outlet for pumped fluid and inlet and outlet ports for a motive fluid, the float being connected to a toggle mechanism which is supported by the cover and is operable by movement of the float to actuate control means for controlling flow of the motive fluid into and/or out of the chamber.

is 9. A pressure powered pump substantially as described herein with reference to, and as shown in, the accompanying drawings.

Amendments to the claims have been filed as follows -9 CLAIMS 1. A float operated pumping device comprising a float supported within a chamber by a lever which is rigidly connected to the float and is pivotably supported for movement about a pivot axis which is fixed within the chamber, so that the float is movable upwardly and downwardly within the chamber in response to the level of liquid in the chamber, the chamber having an inlet and an outlet for pumped fluid and inlet and outlet ports for a motive fluid, the lever having an extension which is rigidly connected to the -lever, a spring support being carried by the extension for movement relatively to the extension about a pivot axis passing through the spring support and the extension, the spring support comprising an input element of a toggle mechanism which is operable by movement of the float to actuate control means for controlling flow of the motive fluid into.and/or out of the chamber, and the lever being operatively connected to a valve controlling the flow of the pumped fluid through the outlet.

2. A device as claimed in claim 2, in which the float is mounted on an arm to which the lever is rigidly attached.

3. A device as claimed in claim 1 or 2, in which the lever is connected to the arm at one end of the arm, the other end of the arm being rigidly connected to the extension.

4. A device as claimed in claim 2 or 3, in which the arm extends generally parallel to the direction of travel of the float.

5. A device as claimed in any one of claims 2 to 4, in which the point of connection of the float to the io-, arm is nearer to the pivot axis than is the pivotable connection between the extension and the spring support.

7. A device as claimed in any one of the preceding claims, in which the chamber is formed within a housing comprising a bowl portion and a cover, the lever and the toggle mechanism being supported on the cover and the motive fluid inlet and outlet ports and.the pumped fluid inlet and outlet being formed in the cover.

8. A pressure powered pump substantially as described herein with reference to, and as shown in, the accompanying drawings.