US2347903A - Pulsation damper - Google Patents

Description

May 2, v1944. H. GLUCK ET AL PULSA'IION DAMPER :s Sheeis-Sheet 1 Filed Nov. 16, 1942 M y 2, 1944- H. GLUCK ET AL 2,347,903

PULSATION DAMPER Filed Nov. 16, 1942 3 Sheets-Sheet 2 F- IE.4.

BY: Z

EIR ATTOR Y.

y 1944. H. GLUCK ET AL 2,347,903

PULSATION DAMPER Filed Nov. 16, 1942 5 Sheets-Sheet 5 Fl -fi- Patented May 2, 1944 2,347,903 PULSATION DAMPER Harry Gluck, and Daniel J. Snyder, Edgewood, Pa.

Application November 16, 1942, Serial No. 465,788

' 2 Claims. (Cl. 138-40) This invention relates to pulsation dampers and more particularly to such dampers that are used for preventing pulsations of a stack draft recorder.

In the gaging and recording of pressures, pulsation in pressure is one of the mainsourcesof trouble. The rapid changes in pressure interfere with the proper recording and gaging of pressure and in some instances the change may be so great that the gage and/or recorder are corder chart obtained while using our pulsation damper. 1

Referring more particularly to the drawings, reference numeral I indicates a stack draft recorder which is to be protected by our pulsation I damper. This recorder is connected to the stack damaged thereby. When a recorder is usedit is not obtained.

To our knowledge, the only other instrument used for pulsation control is a damper having spiral constricting tubes. If these become clogged with dirt, or are damaged in any way, the damper must be completely replaced. If it is desired to decrease or increase the dampening effect, another damper must be substituted.

It is an object of this invention to make a damper; which can be easily cleaned and which has a replaceable dampening unit.

Another object is'to obtain a clear recorder chart which can be easily planimetered.

Still another object is to provide for gage adjustment without breaking any of the pipe connections.

A further object is to provide a safety tap on the damper to protect the gage against sudden linesurges.

These and other objects will be apparent from the following description and drawings in which Figure 1 is a layout of an installation of the pulsation damper;

Figure 2 is a cross-sectional view ofthe pul' sation damper;

Figure 3 is an end view of the removable cartridge;

Figure 4 is a reproduction of a draft gage recorder chart obtained without using our pulsation damper; and

Figure 5 is 'a reproduction of a draft gage reby means of piping 2, the pulsation damper 3 and the piping 4. A needle valve 5 in the line I acts as a shut-oil! valve.

As best shown in Figure 2, the pulsation damper consists of a body 6 having a threaded connection 'I for connection to the inlet piping 4 and a threaded connection 8 for connection to the outlet piping 2. The body 8 is hollow and has a threaded connection 9 for receiving a removable cartridge III which supports a plurality of capillary tubes l I. This cartridge may be replaced by another cartridge having diflerent resistance to flow. If it is desired to use the same cartridge to obtain a different resistance, one or more of the tubes Il may be plugged. A groove 12 in the cartridge enables it to be easily removed by means of a screw driver. As the pressure in the line varies the pen of therecorder will vibrate, giving a blurred effect as shown in Figure 4. The pulsation damper by means of the restriction of flow in the capillary tube ll prevents the rapid fluctuation of the recorder pen l3. when it is desired to have greater restriction to flow, we may decrease the number of tubes or increase their length and/or 1 decrease their diameter. By varying these three factors any desired restriction-to flow may be obtained.

.If the'fluid in the line is dirty, the tubes ll may be protected by'inserting a strainer on the inlet side of the tubes. If the tubes H become dirty, they may be cleaned by means of a wire. Such cleaning is not possible when using a spiral pulsation damper.

In previous installations, if it were desired to calibrate the instrument, it was necessary to break the connections in the line. To overcome this, a pressure tight plug it is screw-threaded into the body 6. This plug contains a threaded bore IE, to which a pet-cock I8 is connected. Thegcalibrating instrument may be connected to the pet-cock and therefore it is not necessary to break any connection in the line.

To protect the instrument from damage on account of sudden surges in pressure, there is a tap I! in the body or the end opposite plug H. To this is connected a safety seal l8. In case the line impulse should go over the maximum recorder element pressure, the. safety connection for the A safety pop-oi! valve or other safety device may be used in place of the U tube.

While the invention has been disclosed as applied to a stack draft recorder. it may be applied to any recorder or gage using a fluid medium such as air, gas, oil, water. and steam, as long as the medium is not too viscous to ilow through the capillary tubes. The medium used will determine the kind of material to be used in constructing the pulsation damper. Ordinarily the damper is made of non-corrodible material and the strength is varied in accordance with the pressure to be gaged.

Briefly the operation the damper is as follows:

The needle valve 5 operates as a shut-off valve.

When pulsations occur, they are dampened as they are transmitted through the capillary tubes. thus increasing or decreasing the pressure on the instrument side gradually instead of suddenly, until equal pressures are again achieved. This allows the element in the recorder to oscillate correctly at each pressure change, rather than recording extremely high or low due to the pulsations. This achieves our purpose or obtaining readable and accurate charts, which may be readily planimetered as is apparent from an inspection of the chart shown in Figure 5. This chart plainly shows the difference in checker resistanceof the open hearth furnace and shows all furnace reversals. Advantages of the pulsation damper are adjustment by means of the needle valve improves the readings. but this requires constant attention and the readings are not as clear as those obtained when using the damper. In case the line impulse goes over the maximum recorder element pressure, the safety connection on the damper enables the line impulse to bleed directly to the atmosphere. When it is desired to calibrate the instrument, it is only necessary to close shut-oi! valve I, connect pet-cock II to the calibrating instrument and open pet-cock ll. When cleaning or replacing the removable cartridge ll, valve lis closed. the plug it is removed, and the cartridge unscrewed irom the body.

While a particular modification of our invention has been disclosed and described. it will be apparent that we do not wish to be limited exactly thereto. since various modifications may be made while remaining within the scope of the following claims.

We claim:

1. A pulsation damper comprising an elongated hollow body open at one end, an inlet at one end of the body connected to a source of fluidpressure, an outlet at the other end oi. the body connected to a pressure gage, a removable cartridge within the body located between the inlet and outlet, a plurality of capillary tubes extending lengthwise of the body and supported by the cartridge, and a plug for closing the open end of said body. said plug having a diameter of suiflcient size to permit removal of said cartridge from said body.

2. A pulsation damper as defined in claim 1 having a pressure release device attached to the body between the inlet and removable cartridge.

HARRY GLUCK. DANIEL J. SNYDER.

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