INSTRUCTION MANUALPADDLE TYPE LEVEL SW ITCH

MODEL： PRL

Meanings of indications for safety used in this Instruction Manual are as follows.
WARNING:

Indicates that improper handling assumes the risk of a fatal or serious injury.

CAUTION:

Indicates that improper handling assumes the risk of injury or damage to property only.

TOWA SEIDEN INDUSTRIAL CO., LTD.
HEAD OFFICETOKYO OFFICENAGOYA OFFICE

Phone: 81-6-6340-5522, Fax: 81-6-6340-5519
Phone: 81-3-5484-2171, Fax: 81-3-5484-2175
Phone: 81-52-937-5817, Fax: 81-52-937-5836

OSAKA PLANT

Phone: 81-6-6340-2831, Fax: 81-6-6349-6551

URL http://w w w .tow a-seiden.co.jp№EHP1000-3
2011.12.20

Contents[1] Operating Principle .........................................................................................................

1[2] Standard Specifications ..................................................................................................

1[3] Models .............................................................................................................................

2[4] Cautions for Handling .....................................................................................................

4

a. Determination of installation site .........................................................................

4b. Impact of powder particles ..................................................................................

4c. Vibration of hopper ..............................................................................................

4d. Relationship with transport equipment ...............................................................

4e. Slide flange type .................................................................................................

4[5] Cautions for Connection ............................................................................................

5

a. Level switch external terminals ...........................................................................

5

a-1. Power Supply ....................................................................................................

5

a-2. Signal ................................................................................................................

5

a-3. Circuit of switch with lamp/with pulse contact ..................................................

6

a-4. Check change of detection signal ....................................................................

7b. Wiring used and piping, air purge specifications ................................................

8c. Attachment and detachment of cover ..................................................................

9[6] Key Point Inspection ..................................................................................................

9<Inspection of internal mechanism> .......................................................................

9[7] Torque Adjustment .....................................................................................................

10[8] Repair and Replacement Method .............................................................................

10

a-1. Attachment of blade ..........................................................................................

10

a-2. Attachment of wire ............................................................................................

11

a-3. Attachment of extension shaft ..........................................................................

11b. Replacement of internal mechanism ...................................................................

12b-1. Detachment of cover ........................................................................................

12b-2. Detachment and attachment of internal mechanism .......................................

12b-3. Assembly after replacement .............................................................................

12[9] Operation Checking Method .....................................................................................

13[10] Trouble Prevention ..................................................................................................

13[11] Examples of Defects ................................................................................................

14

PRL Model Instruction Manual
Outline drawing (Model: PRL-100)
Aluminum casting Aluminum castingO-ringAluminum casting

Conducting
wire outlet[1] Operating Principle
This product a blade attached to the main shaft is rotated by a motor. When there is noload applied to the blade by an object to be measured, it is always rotating, however, when
the rotation of the blade is stopped by the object to be measured, the rotation of the motor
is stopped and the contact output is issued. It is structured so that the motor power is cut
off at this point to protect the motor.
In addition, when the force to stop the rotation of the motor is removed, it starts rotation by
powering on the motor, and the contact output is also changed over. Existence of an
object to be measured is detected by such action.
[2] Standard Specifications
Power voltage

100/110V AC 50/60Hz, or 200/220V AC 50/60Hz

Attaching method

Flange attachment JIS 5K65A

Power consumption

2.5W

Contact output

1C contact 250V AC 5A (resistance load)

Detection torque (*1)

About 10.0 N cm

Slip torque (*2)

About 30.0 N cm

Rotation speed

1 rpm
Main body case, flange: aluminum casting

Material

Main shaft, blade: SUS304
Seal: nitrile rubber

Operating temperature

Inside the tank: 70 C max.
Outside the tank: 55 C max.

Operating pressure

Inside the tank: 0 - 196 kPa

Paint color

Munsell 10YR7.5/14

Please contact us for specifications of other models.
(*1) The detection torque means the torque value required to stop rotation of the motor.
(*2) The slip torque means the torque value to make the motor protection slip mechanism
start functioning in a case of overload or impact applied to the blade.
1[3] Models

PRL－ □□□□

Type of level switch
1

Standard type2

High temperature type5

Strong type

0

With aluminum alloy coating

2

SUS304 pasted (on the powder contact surface)

3

SUS316 pasted (on the powder contact surface)

4

Made of SUS304

5Made of SUS316

7Screw-in type8

Titanium pasted (on the powder contact surface)

Material of flange

Existence of protective tube, material
0

None

1

SUS3042

SUS316

4

Titanium
Other specifications

EA, EC

Fixed type with extension shaft

EB, ED

Extension and contraction type with extension shaft

F

2 flanges

S

Special specification of seal partJ

Specifications considering earthquake resistanceG

Double protective tube air purge, air cooling specification

N

Withstand load low cost (only applicable for 500N)

W

Wire type (only applicable for 500W)

P

With pulse output

Z

Very small load specification

KC

With indoor specification connector

KW

With outdoor use connector* The other specifications can overlap depending on the combination.

2

Outline drawings (other standard models)Model PRL-101, Protective tube type
Aluminumcasting

Aluminumcasting

Model PRL-100F/200F, 2 flange type
Aluminumcasting

AluminumcastingO-ringAluminumcasting

Aluminumcasting

Conducting
wire outlet

WasherAluminumcasting

Model PRL-500, Withstand load typeO-ringAluminumcasting

Aluminumcasting

AluminumcastingO-ringConducting
wire outlet

Aluminum

Aluminumcasting

Model PRL-500N, Withstand load typeO-ringAluminumcasting

Aluminumcasting

AluminumcastingO-ringAluminumcasting

Seal
Silicon rubber
Conducting
wire outlet

Conducting wire outlet

Model PRL-500W, Wire type
Welding

Aluminum sleeve

Stainless steel
wire rope

Aluminumcasting

Aluminum sleeve

AluminumcastingO-ringAluminumcasting

Conducting wire outlet

Model PRL-100EA/100EC, Fixed type with extension shaft
Stainless springsteel

Aluminumcasting

Aluminumcasting

AluminumcastingO-ringConducting
wire outlet

Model PRL-100EB/100ED, Extension and contraction type with extension shaft
Dimension
variable shaft

Aluminumcasting

Conducting
wire outlet

Model PRL-200, Heat resistance type
Aluminumcasting

Aluminumcasting

Conducting
wire outlet

Model PRL-170, Screw-in type
Nut

O-ringVariable shaft
fixing fitting

Pipe forvariable shaft

Stainless springsteel

Aluminumcasting

AluminumcastingO-ringAluminumcasting

Variable shaft
tightening fitting
Conducting wire outlet

3[4] Cautions for Handling
CAUTION

When attaching at an upper position

a. Determination of installation site
Install it at a position where the powder

Bad example

Good example

particle level actually changes.
b. Impact of powder particles
When installed directly below dropping at
the feeding port, etc., of powder particles,or due to impact of collapse in the bridge
phenomenon inside the hopper, etc., it may
be broken. Change the installation site, orWhen attaching at a lower position

provide a protective plate.
Bad example

Good example

c. Vibration of hopper
Avoid a place where mechanical vibrationof the hopper itself or vibration from avibrator, etc., are applied for long hours.
It may affect the detection action, and lifeof the level meter itself.
d. Relationship with transport equipment(Examplesforreferenceof

Full
Conveyor

conveyortransportation)◎ Level meter for “full” signal
Attach it to a position where it does not go

Empty

over even if all the remaining measured
objects on the conveyor enter the hopper.
◎ Level meter for “empty” signal
Attach it to a position anticipating the time
when the conveyor starts moving and theraw material is fed after the hopper “empty”

Hexagon socket head bolt

signal is issued.
e. Slide flange typeThe flange part slides toward the blade byloosening the hexagon socket head bolt.
Attach it to a position under good condition.
After determining the position of the flange,
firmly tighten the hexagon socket head
bolt.

4

[5] Cautions for Connection
CAUTIONa. External terminals
The color coding of the external terminals
are as shown below.
a-1. Power Supply (wire color of motor)
White and white in the case of 100V AC

Power
supply(110V AC), and black and black in the caseof 200V AC (220V AC).
Motor side

Signal side

Regardless of the voltage, white and blackin the case of shipment from our company

White (black)

White (black)

Red

Power supply

C (common): yellow

Power supply

Power supply

H (“a” contact): red
With lead wire (5-core)

Between C and L: current carrying when

Black

White

Red
Red

Green

power-on state.

YellowGreen

the blade stops in the

Yellow

the blade is rotating.
Between C and H: current carrying when

The colors are provided in the samemanner for one with a lead wire (5-core),
Lead wire (5-core)so wire the signal appropriate for your use

CAUTION

Black

White

Red

Yellow

Greenfrom the terminals.

Contact capacity
Standard: 250V AC 5A

Power supply

Z type (very small load): 250V AC 0.1A

5White (black)

White (black)Red

Yellow

When blade is stopped

GreenWhite (black)L (“b” contact): green

Red

Green

a-2. Signal (1C contact)

White (black)

When blade is rotating

Yellow

CAUTION

The power voltage is pasted on themain body.
As the voltage is displayed on the
nameplate, make sure not to make a
mistake.

Yellow

Green

with lead wire.

a-3. Circuit with lamp/with pulse contact

LED lamp<With lamp>

White (black)

Red

Green

When the blade is rotating, the lamp

Yellow- Blade rotation lamp lighting specification

White (black)<With lamp>

lights up.

Power supply- Blade stop lamp lighting specification
When the blade is at a stop, the lamp

White (black)

White (black)

Red

Green

Yellow

LED lamp

lights up.

Power supply<Pulse lamp>
6 pulses for the blade 1 rotation / 1 minute

LED lamp

White (black)

6 pulses are output for the blade 1 rotation

White (black)

Red<With pulse contact>

Yellow

Green

Pulse generator<Pulse lamp>

Power supply/ 1 minute.
Wire from the 2P terminal of the internalRed

Maximum switching voltage: 1000V DC

Yellow

Green

Maximum contact capacity: 25W
Maximum switching current: 1A

White (black)

Pulse generator

RatingWhite (black)<With pulse contact >mechanism

Power supply<With connector>

KC/KW model (“a” contact) circuit diagram

contact.

White (black)

Red

Green

“a” contact and “b” contact are prepared for

Yellow

For outdoors (Model PRL-100KW)

White (black)

For indoors (Model PRL-100KC)

Black

Red

The

Green

appropriate for your specifications.

White

Power supply

Please designate contact and connector

Connector
pin number

connector for outdoors is a waterproof type.

White (black)

White (black)

Red

Green

Yellow

KC/KW model (“b” contact) circuit diagram

Black

Green

Red

White

Power supply

Connector
pin number

6a-4. Check change of detection signal
Changing of signal
Checking method of signal changeLightly turn the blade counterclockwise forabout 20 .
When the blade is turned counterclockwise
for about 20 ,Between C and H: current carrying state
Between C and L: no current carrying
state
When the blade is returned,

Signal output

Between C and H: no current carrying
state

that, a light clicking metallic sound is madeand the position of the blade is slipped
turning by 90 .
This is a result of the slip mechanism andnot a failure.
Slip torque value
About 30.0 N cm

7

Red

If the blade is turned strongly more than

Yellow

Green

Between C and L: current carrying stateb. Wiring used and piping, air purge
specifications

Conducting wire outlet
Main bodyb-1.
For wiring used, twist wires to crimp with acrimp type terminal (R-3) and then connect
to the external terminal.

Avoid a single

wire whenever possible.

Conducting wire
outlet fitting

b-2.
CAUTION

When using a cable, use a cable with afinished outside diameter 10 to 11.
If the cable size is not appropriate,

Examples of cables that can be used

rainwater or dust, etc., will enter resulting in

CVV (vinyl cable for control)
1.25 mm 4-core, finisheddiameter: 11
2.00 mm 3-core, finisheddiameter: 11

a failure.
b-3.
CAUTION

After wiring, strongly tighten the conducting
wire outlet fitting.

VCT (vinyl cabtire cable)
0.75mm 5-core, finisheddiameter: 10.5
1.25mm 4-core, finisheddiameter: 10.5

It has bushing rubber

inside to tighten the cable and avoid rain or
moisture.
If it is loose, rainwater or dust will enter
resulting in a failure. If a wrong cable size
is used, it may also result in a failure.

Conducting wire outlet(cross sectional drawing)b-4.
Use seal tape, etc., to the piping of air
purge so as not to cause air leakage. IfBushing rubber

there is an intrusion of foreign matter,
Conducting wire
outlet fitting

moisture, etc., into the piping, it may causea defective, so pay attention.
Do not loosen the fixing parts such asflange bolts in a state that pressure isapplied to the paddle type level switch. It
may cause a failure or defective. Whenremoving the paddle type level switch,
previously close the main valve.
The recommended pressure of the air
purge nozzle R1/4” is within the range of
20Kpa to 50Kpa for use. When it is set
slightly higher than the tank inner pressure
within

the

air

purge

recommended

pressure, it is more effective for seal
clogging prevention.
8

outsideoutsideoutsideoutsidec. Attachment and detachment of coverIf the cover is not tightened firmly, rainwater,
moisture, dust, etc., will enter resulting in a
failure.
Observe this especially when it is used
outdoors.
1. Attachment of this cover is a screw-in
type.
2. When removing the cover, pay attention
to the O-ring and loosen the screw toremove it toward you. When attachingit, sufficiently tighten the O-ring andsecurely screw it in.
Firmly and securely tighten the cover by
CAUTIONscrewing in.
Signal use[6] Key Point Inspection

Motor use

<Inspection of internal mechanism>
If the rear cover is removed in theprocedures of item c of [5], the operation
state of the internal mechanism can bechecked. Inspect after referring to item a
Terminal block
mountof [5].

9[7] Torque Adjustment
Spring setting position(standard)

Adjustment of the detection torque isequipped on the mechanism mounting
Strongplate of the rear face (bottom) of theinternal mechanism.

By changing theWeaksetting position of the spring, it can be
adjusted. As for the removing method of
the internal mechanism, refer to b-2
detachment of internal mechanism on page
12.
Avoid adjustment in an unreasonable state
like deforming the spring when adjusting

Change of defection torque (reference)the detection torque. It negates the effectStrongest (position of strong)of the spring disabling detection.

About 10.0 N cm

th

About 19.0 N cm

rd

Weak 4 (4 from the weakest)

Also, avoid using the “weakest” spring

Weak 3 (3 from the weakest)

About 18.0 N cm

setting position whenever possible.

Weak 2 (2nd from the weakest)

About 17.0 N cm

recommended to consider a solution by

Weakest (position of weak)

About 16.0 N cm

changing the blade shape.

* Do not use at the weakest whenever possible.

* Stable

actioncanbeobtained

It is

by

changing the blade shape.
Please consult us for details.

[8] Repair and Replacement Methoda-1. Attachment of blade
The relationship between the main shaft
and the blade boss is as follows.

The

screw A is a left-hand thread. Screw thenut ② into the main shaft ①, place the S
washer ③, and then screw in the blade
boss ④.

When replacing the blade, fix

the nut ② with a spanner, etc., and turnthe blade boss ④ clockwise to remove it.
As a screw locking agent is used for the
thread part, please work carefully.

10

a-2. Attachment of wire
The relationship between the main shaft

Wire attachment holeand the wire (wire boss) is as follows.
The screw A is a left-hand thread. Screw
the nut ② into the main shaft ①, place
the S washer ③, and then screw in thewire boss ④.
When replacing the wire boss, fix the nut② with a spanner, etc., and turn the wireboss ④ clockwise to remove it.

As ascrew locking agent is used for the threadpart, please work carefully.
a-3. Attachment of extension shaft
Mounting EB/ED model extension shaft
1. Apply a screw locking agent on the screw of the extension shaft spring part.
2. Screw the extension shaft into the main shaft of the level meter.

The screw is aleft-hand thread.
3. Tighten it completely to the end with the tightening tool.
4. Loosen the M6 nut of the extension shaft fixing fitting, set to the L dimension in youroperating environment, and then securely tighten the M6 nut. (From the flange end
face to the tip of the blade is the L dimension.)
Extension shaft fixing fitting

Stainless spring steel

S washer

M8 nut *Main shaft

Level meter main body*M6 nut *Use screw locking
agent.

M8 P1 left-handthreadThe * mark shows a position to tighten using a tool

Mounting EA/EC model extension shaft
1. Apply a screw locking agent on the screw of the extension shaft spring part.
2. Screw the extension shaft into the main shaft of the level meter.

The screw is aleft-hand thread.
3. Tighten it completely to the end with the tightening tool.
Stainless spring steel

S washer

M8 nut *Main shaft Level meter main body*Use screw locking
agent.

M8 P1 left-handthreadThe * mark shows a position to tighten using a tool11

b. Replacement of internal mechanism
b-1. Detachment of cover
Work in the state that the power is shut off.
WARNINGIt may result in an electric shock.
As the cover ① is fixed to the main bodycase ② by screwing in, loosen the screw
to remove it toward you while paying
attention to the O-ring ③.
b-2. Detachment

andattachmentofinternal mechanism
Remove the connected external wirings
from

their

terminals.

The

External terminal drawing

internalmechanism is fixed to the main body case
M4 screwwith 2 M4 screws. Remove them with a
Phillips

screwdriverandremoveM4 screwtheinternal mechanism by pulling toward you.
When attaching the internal mechanism,
insert it until a clicking sound is made.

Powersupplyb-3. Assembly after replacement
When the external wirings are connected tothe terminals as they were, attach thecover ①. When attaching the cover, pay
attention not to press the connected
external wirings or not to slacken them
unnecessarily.
Turn on the power after completing the
WARNINGwork.

12

[9] Operation Checking Method
1. Check that the wirings are connected correctly with a tester.
2. Check the insulation resistance between each terminal and ground.
3. Turn on the power supply.
4. Check that the blade and the main shaft are smoothly rotating.
5. Touch the blade by hand or place the entire blade into powder to check that the signal ischanged over.
(2 - 3 positions for 1 turn)
6. Turn the blade by 90 by hand and check that the rotation of the shaft slips.
(2 - 3 positions for 1 turn)[10] Trouble Prevention
1. Do not give impact on the main body.
2. Check that the blade, main shaft, and protective tube are not bending.
3. Pay attention to the attachment of the cover so that no rainwater, dust, etc., enter.
4. Check that no material adheres to the blade or the main shaft.
5. When adjusting the detection torque, do not stretch the spring. It disables detection.
6. Avoid using the “weakest” spring setting position whenever possible.

It isrecommended to consider a solution by changing the blade shape.
7. Do not make a mistake in the power supply voltage when wiring.
8. Do not mistake the power supply terminal for the alarm terminal when wiring.
9. Do not flow overcurrent or short circuit the alarm contact.
10. Use an appropriate crimp terminal and adopt a wiring method that is not easily
disconnected when wiring to the terminal.
11. Do not tighten the attachment screw to the terminal with more than the necessary force.
The screw may break off.
12. Securely construct the conducting wire outlet to prevent intrusion of rainwater.
Examples when abnormality of detection action occurs (outline)
Abnormal state

Material inside tank

There is material,
however, the signal
does not change overto that side.

Bridge is caused by
the material, etc., andthere is a hollow spacearound the blade
resulting in idling of
the blade.
The material isadhered andaccumulated from thetank wall to the blade.

There is no material,
however, the signal
does not change overto that side.

This product failure state
Main shaft rotation

Signal changing

1. Power supply, voltage
2. Motor failure

1. Contact failure of thecontact of the signal
output unit.
2. Contact burning of thedue to overcurrent, etc.

1. Return action failure
due to clogging of theseal part.
2. Failure of the return
spring3. Bending of the mainshaft
4. Deformation of themain body

1. Contact failure of thecontact
2.Contact burning of thesignal output unit due toovercurrent, etc.

13

[11] Examples of Defects (Typical Examples)
1. Defective due to short-circuit accident
When wiring to the internal mechanism, the signal side (L, C, H) and the power supply
side are mistaken.
◎ Only supply power after making sure.
2. Tightening failure of the cover
Especially when using it outdoors, rainwater enters, and corrosion, contact failure, etc.,
occur.
◎ Securely tighten the cover without fail.
3. Defective due to damage of the screws of the cover and the terminal block.
◎ Tighten them with appropriate screwdriver.
4. Defective due to intrusion of rainwater, etc., from the conducting wire outlet.
◎ Securely tighten the conducting wire outlet fitting. And when carrying out piping,also construct securely.
Pay careful attention so as not to touch the terminal block by finger tip, etc. (Watch out for
WARNING

electric shocks)

14