|
BASIC PHILOSOPHY
Transvector Jets and Nozzles are airflow amplifiers capable of using a small amount of compressed air to create an airflow
several times larger. Basic operating concepts concerning Transvector Jets and Nozzles have been covered in on our pages Round
Transvector and Nozzles. Whether noise reduction or energy conservation is the basic aim, blowoff applications of compressed air can be
converted to airflow amplification easily using me same philosophies and techniques.
AIR PREPARATION
Filtration
Transvectors incorporate annular openings through which the compressed air escapes. The open areas can be as narrow
as .002". It is essential to filter the compressed air before supplying it to an airflow amplifier. Five micron filtration with automatic draining is recommended. Our Model 701S-36A is an example of an acceptable filter. The cleanliness of the air as it enters the compressor does not indicate its condition at the point of use. Water generated in compression rusts compressed air pipes, and compressor lubricants find their way into the air.
Unfiltered air is guaranteed to clog airflow amplifiers, sometimes after only a few minutes of operation.
Regulation
Regulating provides still other advantages. If a nonadjustable blowoff jet is used in different ways (as in an
automated machine processing more than one kind of part), the adjustable feature of a pressure regulator will allow setting at the optimum flow for each kind of part. Furthermore, the pressure
gauge on the regulator is a convenient way to indicate proper settings and re-establish them for other adjustments. When using Transvectors, there is no reason to limit air supply pressure to 30
PSIG. It is not possible to stop up or block the flow of air, thus, 30 PSIG could never be indicated by a test gauge at the outlet of a Transvector. In
fact, Transvectors work better at higher pressures and are often used at 80 PSIG or more without effect on their energy savings and noise reduction capabilities.
Other Air Preparation Equipment
Dryers, lubricators, oil removal filters, and other sophisticated compressed air preparation equipment are not required
for Transvectors.
DESIGNING TRANSVECTOR BLOWOFF OPERATIONS
Selecting the Number of Amplifiers
Many open jet blowoffs are 1/4" diameter or smaller. These often can be fitted with one Transvector Jet
or Nozzle and produce good results. Occasionally it is necessary to install more than one Transvector amplifier. It is easy to install a Transvector Jet or Nozzle on a blowgun hose and move it
around by hand to experiment for the desired effect. Before testing this way, however, consider the techniques of positioning and aiming discussed below. Multiple
installations of ampilfiers give you a chance to design the shape of the blowoff stream and tailor it to the target shape.
It may be desirable to install more than one amplifier and operate them at lower pressure even though one amplifier at higher pressure might work.
Positioning and Aiming
The total available blowoff force is diminished if the target is too close or too far from the amplifier. Optimum
distance for maximum total force is 9" to 12" for all models.
There is a correlation between air consumption and total available force. The force experienced by the target is not
necessarily the total available force. A 1" circular target would experience only a small part of the available force if it is placed in a stream 4" or 5" in diameter.
Amplifiers should be placed closer to smaller targets to try to match stream size with target. "Target," in the case of chip removal and similar operations, is the area to be
cleaned.
Regulator Considerations
The regulator is an important element in attaining maximum efficiency. Nonadjustable products such as the Model 901 Transvector Jet should be adjusted by setting the regulator to the lowest pressure that will provide the desired blowoff effect. This assures minimum air consumption and noise.
The adjustable Models 900 and 909, however, are not the same.
For the Flo-gain Nozzle and Set Jet, adjust the regulator output pressure to the lowest expected plant air pressure at the blowoff location. For example, if pressure varies from 75 to 95 PSIG,
adjust the regulator to 75 PSIG.
This will isolate nozzle performance from plant air pressure variations. Adjust the Flo-gain’s Nozzle's or
Set Jet's micrometer adjustment dial for desired blowoff effect. This technique provides the highest operating pressure possible without variation.
Studies have shown that the highest possible pressure associated with the smallest metering gap (dial adjustment)
produces the least noise and consumes less air.
Intermittent Operation
Blowoff Jets are often controlled with solenoid valves (example Our 721T-55) to operate only during certain portions of a
cycle. When controlling noise or conserving energy, attention to the length of the "on" cycle is important. Although individual installations vary, the "on" cycle
should be closely timed to match the stationary time of the target. "On" cycles shorter than this require more air per second and are, therefore, noisier. Longer cycles waste
air and add to total plant noise. Short bursts of old style unregulated open jets are not the proper "on" cycle for Transvector blowoff. This is particularly true in
part ejection from stamping operations.
CALCULATING COMPRESSED AIR SAVINGS
After Transvectors have been installed and the regulator setting and amplifier dial setting needed to do the job have been
determined, the following air consumption data can be used for before-and-after consumption comparisons.
AIR CONSUMPTION (SCFM) CONVENTIONAL BLOWOFF
|
Pressure
(PSIG)
|
2” Long Pipe Nipples nom. pipe size
|
|
1’ Long Copper Tubes
nom. tube size
|
|
Holes in Pipe
Hole Diameter
|
|
|
1/8”
|
1/4”
|
3/8”
|
|
3/16”
|
1/4”
|
3/8”
|
1/2”
|
|
1/16”
|
1/8’
|
3/16”
|
1/4”
|
|
30
|
39
|
68
|
135
|
|
5.6
|
16.5
|
45
|
92
|
|
1.8
|
8.4
|
18.7
|
33
|
|
40
|
48
|
83
|
165
|
|
6.8
|
20.0
|
55
|
113
|
|
2.2
|
10.2
|
23.0
|
40
|
|
60
|
65
|
113
|
225
|
|
9.3
|
27.5
|
75
|
153
|
|
3.0
|
14.0
|
31.1
|
54
|
|
80
|
83
|
144
|
285
|
|
11.7
|
35.0
|
95
|
195
|
|
3.8
|
17.7
|
39.5
|
69
|
|
100
|
100
|
174
|
345
|
|
14.2
|
42.2
|
115
|
236
|
|
4.6
|
21.3
|
48.0
|
84
|
|
PSIG /14.5 = Bar: SCFM x 28.3 = SLPM
|
AIR CONSUMPTION (SCFM) TRANSVECTOR JETS AND NOZZLES
|
PSIG
|
1201
|
1202
|
1203
|
1204
|
1205
|
1206
|
1200 Nozzle Set at
|
901 Jet
|
901B Jet
|
901D Jet
|
909 Jet Set at
|
|
|
|
|
|
|
|
|
.006
|
.008
|
.010
|
|
|
|
.003
|
.006
|
.009
|
|
30
|
3.4
|
|
5.1
|
5.1
|
10.5
|
10.5
|
5.2
|
6.6
|
7.4
|
3.5
|
3.5
|
5.8
|
2.6
|
5.6
|
8.4
|
|
40
|
4.0
|
|
6.0
|
6.0
|
13.6
|
13.6
|
6.4
|
8.2
|
9.1
|
4.4
|
4.4
|
7.2
|
3.1
|
6.8
|
10.3
|
|
60
|
5.4
|
|
8.1
|
8.1
|
18.8
|
18.8
|
8.7
|
11.0
|
12.3
|
5.8
|
5.8
|
9.7
|
4.3
|
9.4
|
14.1
|
|
80
|
6.8
|
|
10.2
|
10.2
|
23.0
|
23.0
|
11.0
|
13.0
|
15.7
|
7.5
|
7.5
|
12.4
|
5.4
|
11.8
|
16.9
|
|
100
|
8.3
|
23.0
|
12.5
|
12.5
|
28.4
|
28.4
|
13.4
|
16.9
|
19.0
|
9.1
|
9.1
|
15.0
|
6.6
|
14.3
|
21.7
|
|
PSIG /14.5 = Bar: SCFM x 28.3 = SLPM
|
PLANNING A PLANT-WIDE CONVERSION
The Method
After an initial experiment with Transvector Jets and Nozzles, the decision to make a plant
-wide conversion to upgrade all blowoffs is still a major one involving careful planning and justification. Use of the following pilot study method will allow projection of plant-wide
costs and savings after converting a relatively small portion of the blowoff jets in a plant.
1. Make a complete survey of blowoff jets used in the plant.
2. Calculate blowoff air usage for each jet.
3. Select a representative sample of jets for the pilot study. Five percent of the total blowoff air usage would be appropriate. This selection should be made carefully to ensure
the blowoffs picked are representative of most blowoff jets in the plant.
4. Outfit the pilot study jets with Transvector Jets and Nozzles and adjust for proper function.
5. Compare before and after air usage for the pilot study and adjust to full plant air savings potential (multiply by 20 if a 5% pilot study was made).
6. Determine the approximate number of airflow amplifiers, regulators, and filters needed and the approximate maintenance time for plant~wide conversion by scaling up pilot study usages.
7. Justify the project using one of the techniques in the following section.
|
|
Current Method
|
Proposed Method
|
|
Product
|
1/4” x 1’ length copper tube
|
Model 1200 Flo-gain Nozzle at .006”
|
|
Air Pressure
|
100 PSIG
|
100 PSIG
|
|
Duty Cycle
|
100%
|
100%
|
|
Consumption
|
42 SCFM
|
13 SCFM
|
|
Annual Operating
Cost
|
42 SCFM x 60min.
= 2520 SCFH
2520 SCFH x 16 hrs. (2 shifts) = 40,320
st.cu.ft./day
40,320 SCFD x 250 days
= 10,080,000 st.cu.ft./year
10,080,000 SCFYx.26/1000SCF
= $ 2,620.80 / year
|
13 SCFM X 60 Min = 780 SCFH
780 SCFH x 16 hrs. (2 shifts)
= 12,480 st.cu.ft. / day
12,480 SCFD x 250 days
= 3,120,000 st.cu.ft./year
3,120,000 SCFY x .26/1000SCF
= $ 811.10 / year
|
|
|
Annual Cost Savings =
$ 1,809.60 / year
|
|
|
Pay Out Analysis
|
Cost of 1200 Flo-gain nozzle $ 14.00
Installation Cost
(est.) $ 30.00
Total $ 44.00
Installed cost / annual savings =
.024 pay-out factor
.023 x 365 days
= 8.875 days pay-out
|
|
Justification
The most common means of justifying is based on compressed air savings. Compressed
air costs between 20 and 30 cents per 1000 cubic feet. If you haven't developed costs specifically for your plant, use $ 0.26 per 1000
ft3 Take total projected CFM savings times minutes plant works per year times $ 0.26 per 1000 ft3 for annual savings. Compare with
nozzle costs and installation costs to get payback time, return on investment, etc.
It is also possible to justify adding Transvector blowoff by showing that new compressors
will not be required. Any capital savings of this type are in addition to the compressed air savings mentioned above.
|
